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MAINTENANCE/TROUBLESHOOTING

 

D. 

OPTION MOTHERBOARD (P/N 35007) 

 
The option motherboard is used in order to expand the capabilities of the ExacTime.  It 
provides a computer buss command interface to option assemblies, if required, as well as 
basic 1pps, 10MHz, 5MHz, 1MHz, IRIG B and other signals that may be required for option 
expansion.  The option slots (1-4) provide this information to optional plug-in assemblies 
(see the ExacTime Configuration Guide for a list of the option assemblies available).  For 
this example the only option assemblies plugged in are the 1MHz and 5MHz sine wave 
shapers.  The sine wave shapers simply take the 1MHz or 5MHz TTL square wave signals 
provided on the buss interface and provide a sine wave output to the rear panel BNC 
connectors on the option motherboard.  The option motherboard provides buffers before the 
signals go the BNC connector so as to prevent and damage should the output be shorted for 
any reason.  Additional options could be added to this configuration as there are two 
additional slots available for customer expansion.  Should any of the option outputs fail it is 
a simple matter to determine if the buffer has failed or the module assembly has failed by 
swapping the modules.  The sine wave shapers are interchangeable and can be plugged in to 
any slot or from another unit.  Power is provided to the assembly through a parallel cable 
from the power supply. 

 

E. 

X72 RUBIDIUM OSCILLATOR (OPTIONAL) 

 
The internal oscillator can be an X72 Rubidium Oscillator.  Its interface to the GPS Main 
board (100015) is through a cable assembly attached to connector J23.  The 10MHz 
frequency output and the control voltage to adjust the frequency of the oscillator are via this 
cable assembly.  The control voltage is provided by a digital-to-analog converter on the main 
assembly.  It is used to discipline (control) the frequency output to the GPS reference.   

 

5.3.4  MICROCOMPUTER PROGRAM THEORY OF OPERATION 

 
The microprocessor clock provides a system where by the time as well as the frequencies generated 
are “disciplined” i.e. phase locked to the GPS reference information.  Looking at Figure 5-1 there are 
two things that form the interface between the receiver and the clock.  The first is an RS-422 I/O that 
provides all of the operating commands, status, and GPS data to the clock.  The second is an on-time 
1pps reference pulse. Once the receiver has positioned the 1pps reference, and after it begins 
tracking satellites, the difference (BIAS) between the 1pps reference and the real “on-time” 1pps is 
measured.  During the “Oscillator Stabilize” phase, the clock will take this BIAS information and 
control the internal oscillator’s frequency to correct for any frequency offset.  When the unit turns on 
the LOCK LED, the current BIAS information is measured again and the difference (after much 
filtering) is used to control the frequency of the internal oscillator. 
 

Symmetricom Inc 

ET6xxx ExacTime GPS TC & FG (Rev C) 

5-9

 

Содержание ET6000

Страница 1: ...0 ET6010 ET6500 ExacTime GPS Time Code And Frequency Generator Covering Configurations ET6000 ET6010 ET6500 TCXO ET6000 ET6010 ET6500 OCXO ET6000 ET6010 ET6500 RB1 Revision C User s Guide 8500 0105 June 2005 ...

Страница 2: ...ACE 1 8 1 4 6 INTERNAL TIME BASE 1 8 1 4 7 PRIMARY POWER 1 11 1 4 8 DIMENSIONS 1 13 1 4 9 WEIGHT 1 13 1 4 10 ENVIRONMENT 1 13 1 5 ADDITIONAL SPECIFICATIONS 1 14 1 5 1 ANTENNA PREAMP 1 14 1 5 2 GPS RPU AND ANTENNA 1 14 1 6 FUNCTIONAL CHARACTERISTICS 1 14 1 6 1 ACQUISITION 1 14 1 6 2 SIGNAL INTERRUPTION 1 15 1 6 3 POSITION AND VELOCITY SOLUTION 1 15 1 6 4 DYNAMIC CAPABILITY 1 16 1 6 5 RF JAMMING RES...

Страница 3: ...6 4 1PPS INPUT 2 8 2 6 5 OSCILLATOR CONFIGURATION 2 8 CHAPTER THREE OPERATION 3 0 INTRODUCTION 3 1 3 1 OPERATIONAL STEPS 3 1 3 1 1 INITIALIZATION UNKNOWN POSITION 3 1 3 1 2 INITIALIZATION KNOWN POSITION 3 3 3 2 OPERATIONAL CHARACTERISTICS 3 4 3 3 LIQUID CRYSTAL DISPLAY 3 4 3 3 1 MAIN MENU SCREEN 3 4 3 3 2 POSITION MENU SCREEN 3 9 3 3 3 SET UP MENU SCREEN 3 10 3 3 4 RS232 I O CONFIGURATION MENU SCR...

Страница 4: ... 4 10 4 14 DISABLE TIME INTERVAL 4 10 4 15 REQUEST TIME INTERVAL 4 10 4 16 REQUEST ELEVATION MASK ANGLE 4 11 4 17 ENTER ELEVATION MASK ANGLE 4 11 4 18 ENABLE DISCIPLINING 4 11 4 19 DISABLE DISCIPLINING 4 11 4 20 ENTER POSITION 4 12 4 21 ENTER DAC VALUE 4 12 4 22 REQUEST DAC VALUE 4 13 4 23 NUMBER OF POSITION AVERAGES 4 13 4 24 ENTER LOCAL OFFSET 4 13 4 25 ENTER CABLE DELAY 4 14 4 26 REQUEST CABLE ...

Страница 5: ...ON 4 26 4 49 3 SET AUTO DAYLIGHT SAVINGS TIME DEFAULT INTERVAL 4 26 4 49 4 REQUEST AUTO DAYLIGHT SAVINGS TIME INTERVAL 4 27 4 49 5 SET AUTO DAYLIGHT SAVINGS TIME INTERVAL 4 27 4 50 REQUEST UNIT SERIAL NUMBER 4 28 CHAPTER FIVE MAINTENANCE TROUBLESHOOTING 5 0 MAINTENANCE 5 1 5 1 ADJUSTMENTS 5 1 5 1 1 INTERNAL OSCILLATOR CALIBRATION 5 1 5 1 2 LCD ADJUSTMENT 5 3 5 1 3 AC CODE ADJUSTMENTS 5 3 5 1 4 10M...

Страница 6: ... 9 APPENDIX A ASCII CHARACTER CODE TABLE PART ONE A 1 PART TWO A 2 PART THREE A 3 PART FOUR A 4 APPENDIX B GLOSSARY OF TERMS A B 1 B B 2 C B 2 D B 3 E B 3 F B 4 G B 4 H B 5 I B 5 J B 6 K B 6 L B 6 M B 7 N B 7 O B 8 P B 8 Q B 9 R B 9 S B 9 T B 10 U B 10 V B 10 W B 11 X B 11 Y B 11 Z B 11 Symmetricom Inc ET6xxx ExacTime GPS TCode FG Rev C v ...

Страница 7: ...Rubidium Time Base 10MHz Oscillator X72 C 45 GPS Opt 21A 10MHz Sine Wave Shaper C 47 GPS Opt 23A 23B Lightning Arrestor w 25 or 50 ft Antenna Cable C 48 GPS Opt 27A B C D Signal Distribution C 53 GPS Opt 33A 1 544 2 048MHz Square Wave Output C 56 GPS Opt 33B 33C T1 E1 Framed Ones Balanced Output C 57 GPS Opt 33D 33E T1 E1 Framed Ones Balanced Output w Frame Marker etc C 65 GPS Opt 40 40P GPS Optio...

Страница 8: ...tor ET6010 OCXO ET6500 OCXO ET6000 RB1 10MHz Rubidium Oscillator with an aging rate of 5E 11 per month ET6010 RB1 ET6500 RB1 1 1 USER S GUIDE SUMMARY This User s Guide is divided into the following chapters A CHAPTER ONE GENERAL INFORMATION This chapter includes a general description of the GPS Timing Unit and provides technical specifications B CHAPTER TWO INSTALLATION Describes initial inspectio...

Страница 9: ...nd three spares The satellites are located in six different orbital planes inclined approximately sixty degrees to the equator at altitudes of 10 400 miles above the earth The GPS Timing Unit determines time and frequency by measuring the time of arrival of the precise timing mark and measuring the Doppler effect from one satellite A previously entered or determined position allows computation of ...

Страница 10: ...time and frequency monitoring requires only one satellite once accurate position data has been acquired or entered although the receiver will use as many satellites as available In AUTO mode and the Dynamic mode a minimum of four satellites are required for the GPS Timing unit to do three dimensional latitude longitude and altitude position fixes The basic GPS Timing Unit configuration includes th...

Страница 11: ...r E TRACKING CHANNELS Eight parallel F RECEIVER FREQUENCY L1 1 575 GHz C A Code G ACQUISITION TIME Time to first fix is less than 5 minutes with timing accuracy better than two μS and frequency accuracy better than 1E 8 Full system accuracy with oven OCXO oscillator is provided within 2 hours after LOCKED 1 4 2 TIMING OUTPUTS Rear panel BNCs J4 through J9 can output a 10MHz sine wave IRIG B AC var...

Страница 12: ...rrected jammed to on time using the 1PPS from the GPS Receiver Module In this mode the 1PPS output can jump C J6 1PPS This output is a thirty to fifty μsec wide pulse at CMOS levels The rise and fall times are 6 nanoseconds It is positive rising edge on time within 125 nanoseconds relative to either UTC or GPS with six or more satellite averaging with 95 confidence D J7 10MHz SINE WAVE This output...

Страница 13: ...DB9 connector can output data to an RS232 compatible serial printer or terminal It can be configured to operate in the Standard RS232 output or the One Second RS232 ASCII Burst Mode output For the operation and configurations refer to Chapters Three and Four H OPTIONAL PULSE RATE OUTPUTS The following is a list of optional pulse rate outputs available for selection on BNC connectors J4 J9 They are...

Страница 14: ... this User s Guide EXTERNAL FREQUENCY MEASUREMENT MODELS ET6000 AND ET6010 ONLY Frequency Range 1Hz to 10MHz discrete whole numbers not fractional parts Input Wave Form From 1Hz to 10MHz Rectangular or square wave minimum pulse width fifty nanoseconds Amplitude Range Logic 0 0 2V 0 2VDC Logic 1 2 4V to 15VDC Input Wave Form From 100KHz to 10MHz Sinusoidal Amplitude Range 1 5 volts peak to peak SIN...

Страница 15: ...ength and stop bits are selectable See paragraph titled Fourth Menu Screen RS232 I O Configuration in Chapter Three of this User s Guide A description of the remote control functions is contained in Chapter Four 1 4 6 INTERNAL TIME BASE This unit can have one of three internal time bases depending on customer requirements Unless otherwise specified the following are the specifications for the osci...

Страница 16: ...al manual trimmer VOLTAGE CONTROL 3 0PPM minimum from 0 5 to 4 5 VDC B LOW NOISE OVEN OSCILLATOR Configuration OCXO with the following specifications OUTPUT FREQUENCY WAVEFORM 10MHz Sine Wave OUTPUT AMPLITUDE OF CRYSTAL OSCILLATOR 1 0 volt RMS into 50 ohms AGING RATE 5 x 10 10 per day 5 x 10 8 per year TEMPERATURE STABILITY 1 x 10 8 over a temperature range of 20ºC to 75ºC OPERATING TEMPERATURE 20...

Страница 17: ...z 120 dBc Hz 100Hz 140 dBc Hz 1KHz 144 dBc Hz 10KHz 144 dBc Hz 100KHz 144 dBc Hz C RUBIDIUM OSCILLATOR either X72 or LPRO with the following specifications OUTPUT FREQUENCY WAVEFORM 10MHz Sine Wave OUTPUT AMPLITUDE OF OSCILLATOR 0 55VRMS 0 05VRMS into 50 ohms AGING RATE 5 x 10 11 per month 5 x 10 10 per year OPERATING TEMPERATURE 20ºC to 70ºC measured at the base plate STORAGE TEMPERATURE 55ºC to ...

Страница 18: ...e a Power Entry Module and the Standard Power Supply Input Voltage AC 85 to 264 VAC 47 440 Hz less than thirty watts DC 120 to 373 VDC Input Frequency Range 47 to 440 Hz Note When using 120 VAC install 1 Amp Line Fuses When using 220 VAC install Amp Line Fuses Fuses are found in the Shipping Kit Model ET6500 utilizes a Power Entry and Alarm Relay Module Assembly 55191 and the Standard Power Supply...

Страница 19: ...ll Amp Line Fuses Fuses are found in the Shipping Kit All input outputs from the 55191 are from a rear panel terminal strip TB1 All input outputs have metal oxide varistors for transient voltage suppression The pin assignments for TB1 are shown below as viewed from the rear of the unit TB1 1 TB1 12 Pin Assignments TB1 1 AC HI Input TB1 2 AC LO Input TB1 3 Chassis Ground TB1 4 Fault Relay Common Co...

Страница 20: ...a contact closure until the unit has achieved oscillator lock For example until the front panel LOCKED LED illuminates 1 4 8 DIMENSIONS Chassis Height 1 75 Inches Model ET6010 is 3 50 Inches Width 17 Inches Depth 12 Inches Maximum 1 4 9 WEIGHT ExacTime Unit Approximately ten pounds Antenna Preamp Less than 1 5 pounds 1 4 10 ENVIRONMENT A OPERATING TEMPERATURE ExacTime Unit 0o C to 50o C Antenna Pr...

Страница 21: ... s Guide for selection and an explanation of each MODE SELECTION using the front panel LCD and Keyboard Mode selection may also be made via the RS 232 Interface See the paragraph titled Select Mode in Chapter Four for mode selection using the RS 232 I O The GPS RPU has an eight parallel channel design capable of tracking eight satellites simultaneously The module receives the L1 GPS signal 1575 42...

Страница 22: ... changed the Doppler frequency has shifted The GPS RPU must finish its search of previous satellite signals and will then expand the search to reacquire The search time will depend on the amount of velocity change but it is usually within fifteen seconds If the signal is regained within one minute the expanding frequency search will already have begun cycling In this case reacquisition may require...

Страница 23: ... to the greatest extent possible at power up This includes testing the memory systems and processor as well as monitoring the performance of the channel processors Should a failure occur in any of these areas it will be available as status on the RS 232 I O and will be displayed on the LCD Display as an error 1 6 7 GPS POSITION SOLUTION MODES The user may select either the Auto Mode or the Dynamic...

Страница 24: ...switch to the STATIONARY mode 1 6 8 ELEVATION MASK ANGLE This mask is used to specify the elevation angle below which the use of satellites is prohibited Signal integrity from satellites very low on the horizon can be degraded Obstructions will block the signal For land based applications where there are local obstructions foliage buildings etc system performance will be smoother with an elevation...

Страница 25: ...fset sign 0 1 P65 15 Time Offset Binary 1 Offset from coded IRIG B time to UTC time P66 16 Time Offset Binary 2 IRIG coded time plus time offset including P67 17 Time Offset Binary 4 sign equals UTC time at all times offset will change during daylight savings P68 18 Time Offset Binary 8 P69 N A P7 Position identifier number P70 19 Time Offset 0 5 Hour 0 none 1 additional 0 5 h time offset P71 20 T...

Страница 26: ...hassis slides are recommended if the unit is to be installed in an equipment rack If slides are not used a supporting bar or tray should be provided for the rear of the instrument The chassis slides attach to the sides of the GPS Timing Unit To mount it using the optional slide mounting kit use the eight 6 self tapping screws provided in the kit CAUTION General Cautions Hazards to be considered wh...

Страница 27: ...erproof housing suitable for permanent installation in an exposed location The unit should be located with an unobstructed view of the horizon for optimum tracking conditions The signal will not penetrate foliage Multi path signals may be generated from vertical surfaces which are above the plane of the base of the antenna preamp The antenna preamp which is designed for fixed ground or marine appl...

Страница 28: ...r One of this User s Guide Models ET6000 and ET6010 utilize a power cord that plugs into a Power Entry Module Note Check the AC line fuses located in the power entry module on the rear panel and assure the correct fuse is installed for the AC Line voltage being used to power the unit The AC line fuses should be 1 Amp for an AC input of 120 volts or amp for an AC input of 220 volts Model ET6500 uti...

Страница 29: ... terminal strip TB1 4 and 5 will provide contact closure upon the following conditions A processor error Channel One error or Channel Two error from the GPS receiver Loss of 5VDC If the DAC value goes below 300 or above 65 000 The timing relay output on the rear panel terminal strip TB1 6 and 7 provides a contact closure until the unit has achieved unit stabilization For example until the front pa...

Страница 30: ...Connector Adapter 5000 0001 Bullet Antenna Mfg P N 25045 10 Dash number is the software revision This is subject to change without notice Note The GPS antenna and cable described in this manual have been replaced as described in Appendix D Antenna Replacement Kit on page D 1 Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C 2 5 ...

Страница 31: ...UD rate parity word length stop bits and interconnections with the equipment This I O port is configured as a DCE and is intended to be used by intelligent peripherals such as a computer The RS 232 I O port uses a standard DB 9 I O connector with the pin configuration shown in Figure 2 2 The RS 232 protocol is described in Chapter Four in the paragraph titled Information Figure 2 2 RS 232 I O Cabl...

Страница 32: ...ing jumper pins blocks on the GPS Main Assembly 100015 as shown in Figure 2 3 and the front panel keyboard or via the RS 232 I O To check or reconfigure these outputs via the front panel keyboard see the paragraph titled Configuration of Rear Panel BNC Connectors J4 J9 in Chapter Three of this User s Guide To check or reconfigure these outputs via the RS 232 I O see the paragraphs titled Request M...

Страница 33: ...a multipurpose input that may also be optionally utilized to record an event or accept a frequency for external measurement purposes 2 6 5 OSCILLATOR CONFIGURATION The jumper blocks at J27 enable the processor and the program to determine which oscillator is installed on the board This provides for the selection of the specific gain and correction voltage i e the discipline voltage for each oscill...

Страница 34: ...1 3 2 4 Buffered Out 1 3 2 4 Buffered Out Relay See Inset Below J24 J25 above are jumpered for Buffered Outputs The diagram below illustrates the jumper positions for Relay Outputs Inset Example Inserting jumper blocks into J14 5 6 and J24 1 2 will output a 10 MHz sine wave on rear panel BNC connector J4 Notes 1 Mux Channel 1 can be output on both J4 and J9 2 Mux Channel 2 can be output on both J5...

Страница 35: ... Mast 711700 Secure to an existing vent pipe using hose clamps or secure to a flat surface using pipe straps and screws Antenna Cable with Type N Connector Note The GPS antenna and cable described in this manual have been replaced as described in Appendix D Antenna Replacement Kit on page D 1 2 10 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 36: ...titled SET UP MENU SCREEN SET MODE this chapter The criteria for selecting the various modes can be summarized as follows AUTO Use if your position i e the position of the antenna is unknown and stationary This is the default mode See section titled Initialization Unknown Position DYNAMIC This mode would be selected if the unit is mounted in a moving vehicle By definition your position is unknown ...

Страница 37: ...r Once the unit s discipline process has stabilized the LOCKED LED will illuminate indicating that the unit is completely functional For a TCXO oscillator this process will take about 30 minutes For a OCXO oscillator this process will take about 90 minutes For a Rubidium oscillator this process will take about 3 5 hours If the LOCKED front panel LED does not illuminate within the specified time ab...

Страница 38: ...her TCXO OCXO LPRO or X72 LPRO and X72 are both versions of a Rubidium oscillator XX A number 10 to 1 indicating the progression through a series of oscillator stabilization steps After the oscillator stabilization step is finished unit stabilizing will begin The unit starts to discipline the internal oscillator Once the unit s discipline process has stabilized the LOCKED LED will illuminate indic...

Страница 39: ...y when it is ENABLED and used as the unit s time base and when the GPS ExacTime is actively tracking a satellite During periods when there are no satellites in view or when the unit isn t tracking the last DAC value is retained and the unit continues to operate normally The outputs are then as accurate as the drift aging rate of the oscillator See Chapter Four paragraphs titled Enable Disciplining...

Страница 40: ...d rate 1 5 10 15 20 25 30 35 40 000 00 00 12 DOING TIME INT CALIB 142 195 073 123 157 056 198 If the MENU key is pressed prior to completing the calibration process the calibration will be interrupted and the process aborted However an additional menu screen this Time Interval Calibration MENU will be enabled The user can access this screen if he cycles through the various menus by pushing the MEN...

Страница 41: ...raph titled Enter Local Time Offset in Chapter Four of this User s Guide to enter the desired local time offset via the RS 232 I O port The local time offset may also be entered into the unit using the front panel keyboard and LCD See paragraph titled Local Time Offset under the SET UP MENU SCREEN in this chapter The letter U or G which is displayed in Row One Column Fourteen denotes whether UTC U...

Страница 42: ...illator reference precision since the last usable satellite was visible Refer to the paragraph titled Set Mode Mode Selection in this chapter The status message ZZZZ Stabilizing XX where the two digit number ten to 00 following ZZZZ Stabilizing represents how far away the oscillator is from stabilization At power on it will be ten and then down count to 00 The length of time the unit has been OFF ...

Страница 43: ...ceiver is reset The error message Ant Undercurrent indicates that the GPS RPU is not providing sufficient current to the antenna The probable cause of this message is a discontinuity in the antenna cable or a failure of the antenna preamp itself Check the antenna preamp cable connections since they are the most likely cause of the discontinuity The error message Ant Overcurrent indicates that the ...

Страница 44: ...ote Depressing the MENU keyboard switch and continuously holding it down for more than two seconds will display the previous menu screen A sample of the Position Menu Screen is shown below Column Row 1 Row 2 Latitude expressed in Degrees Minutes N North or S South is displayed in Row 1 starting at Column 1 It is followed by Longitude expressed in degrees minutes W West or E East Next is the altitu...

Страница 45: ...always available in FLYWHEEL mode 3 3 3 SET UP MENU SCREEN Subsequent pushing of the MENU keyboard switch will display the Set up Menu Screen which is shown below and contains the following choices Column Row 1 Row 2 If the 0 keyboard switch is pressed the operational software version and the current Leap Second will appear in the lower right hand corner in place of SET DAC 1 5 10 15 20 25 30 35 4...

Страница 46: ... the most frequently used mode of operation for timing applications This mode of operation assumes that the current position longitude latitude and altitude is accurate It uses an averaged solution of the time information from as many satellites as the receiver is tracking up to eight For additional information on the STATIONARY mode Chapter Five Choice 4 DYNAMIC Survey Mode Depressing the 4 keybo...

Страница 47: ...r the day of year two digits for the hour two digits for the minute and two digits for the seconds Leading zeroes are required if necessary The GPS receiver will use this TIME input as its time until the time is acquired from a GPS satellite The 1pps output of the GPS receiver will not be on time with UTC or GPS whichever has been selected until the GPS receiver has acquired time from the satellit...

Страница 48: ...phere or a 2 for the Southern Hemisphere and the display will change to that shown below ENTER LONGITUDE XXX XX XXX Using the numeric keys of the keyboard enter the longitude in degrees and minutes to the thousandth of a minute and the display will change to that shown below ENTER 1 EAST 2 WEST Using the numeric keys of the keyboard enter either a 1 for the Eastern Hemisphere or a 2 for the Wester...

Страница 49: ...nput All offset entries are positive 0 00 to 23 5 and are calculated as west of the Greenwich Meridian The current offset will be displayed Pressing the 5 keyboard switch will allow entry of the new offset Example California is eight hours later than GMT The local time offset entry would be 08 0 Japan is nine hours earlier than GMT The local time offset entry would be 15 0 The calculation for nega...

Страница 50: ...word length Keep pressing the 3 keyboard switch to cycle through the choices which are 7 DATA BITS and 1 STOP BIT or 8 DATA BITS and 1 STOP BIT The antenna cable length can be entered by pressing the 5 keyboard switch and entering four digits in feet which corresponds to the length of the antenna cable This will make the 1pps output on time by compensating for the propagation delay of the cable Th...

Страница 51: ...ill look similar to the following Column Row 1 Row 2 This feature provides the ability to preset a coincidence time into the GPS TC FG from hundreds of days through tenths of microseconds When the coincidence time equals the GPS time a 2 microsecond positive going pulse is output This coincidence output is on rear panel BNC J7 Refer to Chapter One 1 5 10 15 20 25 30 35 40 COINCIDENCE D H M S mS uS...

Страница 52: ...onal until satellites are reacquired At that point it won t be operational again until LOCKED has been achieved This function is always available in FLYWHEEL mode The external frequency measurement can be set up configured from either the front panel keyboard and LCD display or remotely via the RS 232 I O port Pushing keyboard switch 1 followed by a number 00000001 to 10000000 will input the frequ...

Страница 53: ...RT S00 E000 5 6 Row 1 Row 2 Single Event Log is operational in the AUTO DYNAMIC and STATIONARY modes when LOCKED with the following qualification If after achieving LOCKED the unit loses satellites and the TRACKING and LOCKED LEDs go out this function will still be operational until satellites are reacquired At that point it won t be operational again until LOCKED has been achieved This function i...

Страница 54: ...MEASUREMENT MENU SCREEN MODEL ET6500 ONLY The 50 60Hz measurement features can be programmed using the front panel keypad switches Cycle through the various menus on the LCD display using the MENU switch until the 50 60Hz Measurement screen appears It will look similar to the following Column 1 5 10 15 20 25 30 35 40 FRQ 60 0001HZ PHASE 123 4 ERR 00 4315S 1 OFFSET 00 0005 4 OFF 5 ON 6 60HZ OFF Row...

Страница 55: ...or calculation Pushing keypad switch number one will program the offset Note that an offset cannot be entered until the measurement is stopped OFF will appear in the lower right hand corner of the LCD display If the unit is not locked ERR will appear If the measurement is started ON will appear Keypad switch number two will select plus and switch number three will select minus The number of second...

Страница 56: ... choices Column 1 5 10 15 20 25 30 35 40 AUTO DAYLIGHT SAVING 1 OFF 1 5 10 15 20 25 30 35 40 MUX OUT 1 CH 1 2 OUTPUT DC CODE 3 5 KEYLOCK OFF Row 1 Row 2 The rear panel BNC connectors J4 through J9 can be configured to output various timing signals using the internal jumper pins and the front panel keyboard If the MUX input to any output buffer is jumper selected one of sixteen inputs to that multi...

Страница 57: ...ut 10KHz and 10Hz Model ET6500 outputs 2PPS and 1PPH Note The MUX outputs can also be read and selected via the RS 232 I O port See paragraphs titled Request MUX Output and Set MUX Output in Chapter Four of this User s Guide The standard configuration is as follows J4 TRACKING TTL J5 LOCKED TTL J6 1PPS J7 10MHz SINE WAVE J8 IRIG B AC J9 IRIG B DC J10 1PPS INPUT Time Interval Measurement Configurat...

Страница 58: ...cted by the front panel keyboard Pushing the 3 followed by 5 front panel keyboard allows the user to enable or disable operation of the front panel keyboard The default condition for Keyboard Lock is OFF This means that the keyboard functions normally If the user wishes to activate Keyboard Lock push the 3 followed by 5 keyboard switch When Keyboard Lock is ON only the MENU key will function Nothi...

Страница 59: ...printer output format either Standard or One Second Burst Standard RS232 Printer Output This printer port provides the ability to output time mode status frequency position and other optional data to an RS 232 compatible serial printer or terminal For the J11 connector pin assignments refer to Chapter One The following are examples of output data 94 027 17 04 38 M0 S00 E00 25 00 00 00 0019 E12 33 ...

Страница 60: ... parity bit odd and one stop bit However this configuration can be changed using the front panel keyboard switches or remotely using the RS 232 I O The data transmission is serial asynchronous by character and the ASCII character code is used The time information is interpreted as being UTC time SOH DDD HH MM SSQ CR LF See Table 1 for the definition of each field contained in this time information...

Страница 61: ...ption Description will be located in Appendix C of this manual 3 4 CONFIGURATION OF REAR PANEL BNC CONNECTORS J4 J9 The rear panel BNC connectors J4 through J9 can be configured to output various timing signals using the internal jumper pins and the front panel keyboard Per Figure 2 3 in Chapter Two the following table details the various outputs available at J4 JUMPER BLOCK J24 JUMPER BLOCK J14 O...

Страница 62: ... AT J7 pins 1 and 2 shorted 1 of 16 selectable Channel 4 Mux outputs pins 3 and 4 shorted IRIG B AC code out pins 5 and 6 shorted 10MHz sine wave output pins 7 and 8 shorted unused Per Figure 2 3 in Chapter Two the following table details the various outputs available at J8 JUMPER BLOCK J28 JUMPER BLOCK J18 OUTPUT AT J8 pins 1 and 2 shorted pins 1 and 2 shorted 1 of 16 selectable Channel 2 Mux out...

Страница 63: ...CHAPTER THREE This Page Intentionally Left Blank 3 28 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 64: ...og on character The second category is an ID ASCII character which is a command to the GPS ExacTime Unit The third category which may or may not be applicable is a series of ASCII data bits to input data into the GPS ExacTime Unit Leading zeros must be used where necessary For example if the number is fifty two and if the data to be entered is a four digit number then it must be entered as 0052 No...

Страница 65: ...able Time Interval u 75 Request Time Interval x 78 Request Elevation Mask Angle y 79 Enter Elevation Mask Angle z 7A Enable Discipline 7B Disable Discipline 7D Enter Position 7E Enter DAC Value N 4E Request DAC Value Q 51 Enter Number of Position Averages 7C Enter Local Time Offset T 54 Enter Cable Delay U 55 Request Cable Delay W 57 Re synchronize Minor Time X 58 Select Default Values Y 59 Extern...

Страница 66: ...le Disable Data Select o 6F Enter Preset Coincidence Time Model 6500 only JR 4A 52 Request MUX output JS 4A 53 Set MUX output K 4B Set Major Time 3C Set Year OD 4F 44 Disable Auto Daylight Savings Time Function OE 4F 45 Enable Auto Daylight Savings Time Function OF 4F 46 Set Auto Daylight Savings Time Default Interval OR 4F 52 Request Auto Daylight Savings Time Interval OS 4F 53 Set Auto Daylight ...

Страница 67: ...cy The user inputs e HEX 24 HEX 65 The unit will respond with a plus or minus sign four digits and an exponent having the weight of parts in 10 9 or 10 12 Example 0579E 09 4 5 PRINT TIME STATUS ERROR CODE AND SATELLITE VEHICLE NUMBERS This command allows the user to print the year day of year hour minute second millisecond status code error code and the vehicle numbers of the satellites being trac...

Страница 68: ...he following 3 digits of day of year 2 digits of hour 2 digits of minute 2 digits of second 3 digits of milliseconds space 3 character status code space 3 character error code space Up to 4 satellite vehicle numbers CR LF Each satellite vehicle is identified by its PRN I D Example 056 12 13 45 768 S00 E00 03 13 20 26 It is the 56th day of the year February 25th The time is 12 hours 13 minutes 45 s...

Страница 69: ...e user to read the accurate position known to the GPS ExacTime unit The latitude will be expressed in units of degrees and minutes labeled North or South relative to the equatorial plane which is defined as zero latitude The longitude will be expressed in units of degrees and minutes labeled East or West relative to the Greenwich Meridian The altitude will be expressed in meters either above or be...

Страница 70: ...ent occurred When this first event has been output the user must respond with a character within three seconds signifying the event information has been taken The unit will then output the second event This process of outputting the data followed by the user s response continues until all events have been output If the user does not take the data and respond with a within three seconds communicati...

Страница 71: ...at there is no data available Event E001 was the last event In the above example S00 indicates no missing events The first event E000 occurred on Channel One at the specified time The second event E001 occurred on Channel One at the specified time 4 9 REQUEST ONE EVENT LOG DATA This command allows the user to request data from any one of the 256 events The user inputs p HEX 24 HEX 70 followed by a...

Страница 72: ...ge of the input pulse is the on time edge of the event When sent this command automatically disables the 1pps time interval function The user inputs 1 HEX 24 HEX 6C and 3 digits The unit will respond with OK followed by CR LF Example 000 The above example will enable the single event log The on time edge of the input pulses will be the negative falling edge 4 11 DISABLE SINGLE EVENT LOG This comma...

Страница 73: ...bove enables the time interval measurement feature and selects the positive edge of the 1pps input as the on time edge 4 14 DISABLE TIME INTERVAL This command disables the time interval measurement The user inputs t HEX 24 HEX 74 The unit responds with OK CR LF 4 15 REQUEST TIME INTERVAL This command allows the user to request the time interval measurement between the internal GPS corrected 1pps p...

Страница 74: ...e indicates an elevation mask angle of five degrees which is the default 4 17 ENTER ELEVATION MASK ANGLE This command allows the user to input change the mask angle The user inputs y HEX 24 HEX 79 05 The unit responds with OK CR LF The above example indicates that the user inputs an elevation angle mask of five degrees 4 18 ENABLE DISCIPLINING This command allows the user to enable the discipline ...

Страница 75: ...esponds with OK CR LF The above example is entering Symmetricom s position of Latitude 33o 48 824 N Longitude 117o 53 397 W Altitude 0026 meters 4 21 ENTER DAC VALUE This command allows the user to manually enter a DAC Digital to Analog Converter value that is used to adjust the internal time base This would typically be done prior to the front panel LOCKED LED turning on if disciplining was turne...

Страница 76: ...ng accuracy of this unit is directly related to the position accuracy The more accurate the position the more accurate the time It is recommended that for timing accuracy of 300 nanoseconds 2 000 to 5 000 position averages be performed to insure an accurate position or input an accurate surveyed position into the unit 4 24 ENTER LOCAL OFFSET This command allows the user to input a desired time off...

Страница 77: ...terrogate the GPS ExacTime unit and find out what cable delay the unit is currently using The user inputs U HEX 24 HEX 55 The unit responds with a four digit number that equates to the length of antenna cable in feet that is stored in memory followed by CR LF Note This command would only be applicable if the user has changed antenna cable length and is unsure what delay has been programmed into th...

Страница 78: ...sition Symmetricom s MUX Outputs CH1 IRIG B DC CH2 10MHz CH3 1pps CH4 10HMz The user inputs X HEX 24 HEX 58 The unit responds with OK CR LF 4 29 EXTERNAL FREQUENCY MEASUREMENT SELECT INPUT FREQUENCY This command allows the user to specify the input frequency User inputs Y HEX 24 HEX 59 followed by eight digits and CR LF The eight 8 digits correspond to the input frequency Leading zeros are require...

Страница 79: ...requency measurement option was enabled The user inputs HEX 24 HEX 5B The unit responds with a or four digits representing the magnitude of drift stability E two digits exponent power of ten space four digits representing the time period in seconds E two digits exponent power of ten 4 32 REQUEST SATELLITE SIGNAL SNR This command allows the user to obtain the signal SNR Signal Noise Density Ratio o...

Страница 80: ...inputs HEX 24 HEX 5E The unit will respond with the following example U M0 D1 L00 LS13 PA0200 PR0 OS0 GPIB17 LK1 Table 4 6 Operating Parameters U UTC sync G GPS sync M0 Mode 0 Auto mode 1 Stationary 2 Dynamic and 5 Flywheel D1 Discipline 1 on 0 off L00 Local time offset LS13 Number 13 of Leap Seconds PA02000 Number of Position Averages PR0 Printer option 0 off 1 on OS0 External Oscillator 0 intern...

Страница 81: ...ts L HEX 24 HEX 4C followed by either a zero or a one Zero for 50Hz measurement one for 60Hz measurement If the unit is not doing measurements the RS 232 will respond with OK CR LF otherwise the unit will respond with CR LF 4 36 ENTER 50 60Hz OFFSET DATA MODEL ET6500 ONLY This command allows the user to enter a starting point for the time error calculation The user inputs D HEX 24 HEX 44 followed ...

Страница 82: ...60Hz measurement data is also available on the 50 60Hz measurement screen of the front panel LCD display The format is as follows FRQ 60 1324HZ PHASE 180 2o ERROR 01 3574S 1 OFFSET 01 206S 4 OFF 5 ON 6 60HZ ON If the 50 60Hz option is not enabled ON will be replaced by OFF When the unit is first turned on it will come up in the OFF default mode If the 50 60Hz option is turned on prior to the unit ...

Страница 83: ...h the Standard RS232 Printer Output and the One Second Burst RS232 ASCII Time Output The user enters I HEX 24 HEX 49 The unit responds with 09600 8 7 N O E 1 2 CR LF Baud Rate 8 or 7 data bits none odd or even parity 1 or 2 stop bits carriage return line feed 4 40 PRINTER PORT MODE SELECTION This command allows the user to specify the printer mode or output format The selection is either Standard ...

Страница 84: ...o the number of seconds Example g0005 The unit responds with OK CR LF carriage return line feed Example g0005 The above example illustrates selecting an output interval rate of five seconds 4 42 PRINTER REQUEST OUTPUT RATE This command allows the user to determine what is the current output rate It is applicable only to the Standard RS232 Printer Output User inputs h HEX 24 HEX 68 The unit respond...

Страница 85: ...eviously turned on Example n101 The unit responds with OK CR LF The above example illustrates the user turning on the printer port not outputting any position information but outputting option data such as external frequency measurement Refer to the following examples of output data 94 027 17 04 38 M0 S00 E00 25 00 00 00 0019 E12 33 48 8270N 117 53 3864W 0028 T1 705337 512 94 027 17 04 43 M0 S00 E...

Страница 86: ...bility to preset a coincidence time into the GPS Time Code and Frequency Generator from hundreds of days through tenths of microseconds When the coincidence time equals the GPS time a two microsecond positive going pulse is output For the specific output connector refer to Chapter One The user inputs o Hex 24 Hex 6F The is the attention log on character The o is the ID ASCII character Then enter s...

Страница 87: ...4 aa CR LF The digits 1 4 correspond to the MUX channels aa two digits corresponds to Table 4 7 Table 4 7 Request MUX Output 00 10MHz 01 5MHz 02 1MHz 03 100KHz 04 10KHz 2PPH 05 1KHz 06 100Hz 07 10Hz 1PPH 08 1Hz 09 1Hz 10 1PPM 11 TRACKING 12 LOCKED 13 5 Volts 14 1pps 15 DC Code 10KHz is output in Models ET6000 and ET6010 2PPH is output in Model ET6500 10Hz is output in Models ET6000 and ET6010 1PPH...

Страница 88: ...ET MAJOR TIME TOD TIME OF DAY This command allows the user to input and change the TOD This command is only useful when the unit is in the Flywheel mode See Chapter Three It consists of the attention log on character the command character and nine characters representing days day of year hours minutes and seconds The user enter K HEX 24 HEX 4B followed by DDDHHMMSS The unit responds with OK CR LF ...

Страница 89: ...d to perform the following functions 4 49 1 DISABLE AUTO DAYLIGHT SAVINGS TIME FUNCTION This command disables the daylight savings time feature The user inputs D HEX 44 The unit responds with OK followed by CR LF carriage return line feed Example OD 4 49 2 ENABLE AUTO DAYLIGHT SAVINGS TIME FUNCTION This command enables the daylight savings time feature The user inputs E HEX 45 The unit responds wi...

Страница 90: ... time of daylight savings Example OR3 4 49 5 SET AUTO DAYLIGHT SAVINGS TIME INTERVAL This command allows the user to program a daylight savings time interval The user inputs S HEX 53 followed by caabbbmmbbbmm where c aa bbb and mm have the same weight value as explained in the REQUEST command Example OS4050920130102 General Specifications If the stop time is greater than the start time then the in...

Страница 91: ...il Last Sunday of October Default Interval Year Julian Day Hour Year Julian Day Hour 0 01 091 01 01 301 02 1 02 097 01 02 300 02 2 03 096 01 03 299 02 3 04 095 01 04 305 02 4 05 093 01 05 303 02 5 06 092 01 06 302 02 6 07 091 01 07 301 02 7 08 097 01 08 300 02 8 09 095 01 09 298 02 9 10 094 01 10 304 02 4 50 REQUEST UNIT SERIAL NUMBER This command allows the user to request the unit s serial numbe...

Страница 92: ... location Y3 A low noise oven oscillator located on the GPS Main Assembly 100015 in location Y1 An X72 or LPRO rubidium oscillator attached to the bottom plate of the chassis assembly This oscillator has no mechanical adjustment There are two methods to null calibrate the internal oscillator Use whichever method is suitable to your means and capabilities A First Method The oscillator can be nulled...

Страница 93: ...nt access hole on the top of the oscillator The low noise oven oscillator located on the GPS Main Assembly 100015 in location Y1 has its access hole on the side of the oscillator There is an access screw used to seal the oscillator that has to be removed first Remember after the adjustment is complete replace the access screw 6 Adjust the oscillator until the 10MHz output is stable with respect to...

Страница 94: ... has changed by more than 5 000 from 32767 repeat steps one through six 5 1 2 LCD ADJUSTMENT The contrast of the LCD display may be adjusted using potentiometer R99 5 1 3 AC CODE ADJUSTMENTS The modulation ratio of the AC code output can be adjusted from a typical range of 2 1 to 6 1 It has been factory adjusted for a ratio of 3 1 The modulation ratio adjustment is potentiometer R107 The code outp...

Страница 95: ...few user serviceable components If severe problems are encountered consult the factory Note When servicing the power supply disconnect the AC power from the unit 5 2 2 POWER LED WILL NOT ILLUMINATE WHEN ON OFF SWITCH IS ACTIVATED DC voltage is not present on J21 input connector pins on Assembly 100015 Table 5 1 J21 Input Connector Pins J21 pin 1 Ground J21 pin 2 12 volts J21 pin 3 12 volts J21 pin...

Страница 96: ... AC power While holding down the MENU key of the keyboard reapply power and observe the LCD display to read COLD RESET DONE UNIT SET TO DEFAULT PLEASE RELEASE COLD RESET SWITCH Release the MENU key of the keyboard The default values have now been loaded into the unit Each of the above default values needs to be examined and changed reentered as necessary See Section 4 31 If the unit is left in the...

Страница 97: ...formance so that an enemy of the United States can not use the system accurately against us in time of a war Although SA is not currently activated it can be at any time The degradation that takes place is from twenty five meters to one hundred meters Spherical Error of Probability SEP for position information and one hundred nanoseconds to 300 nanoseconds 95 of the time for Time information 5 3 2...

Страница 98: ...nformation from as many as eight satellite at the same time The receiver will then provide an average solution of the time information to the ExacTime thus providing a more stable time in which to operate under the effects of SA This is the best timing mode of operation as long as the equipment is in a static environment and a good position has been entered into memory D AUTO MODE The Auto mode is...

Страница 99: ...l of the additional circuits to support the ExacTime s functions The computer provides information to the front panel LCD for display of information to the operators as to the status error and many other operational information and selections It interfaces to the front panel keypad and scans for operator key depressions and displays the selected information All inputs and outputs at the rear panel...

Страница 100: ... parallel cable from the power supply E X72 RUBIDIUM OSCILLATOR OPTIONAL The internal oscillator can be an X72 Rubidium Oscillator Its interface to the GPS Main board 100015 is through a cable assembly attached to connector J23 The 10MHz frequency output and the control voltage to adjust the frequency of the oscillator are via this cable assembly The control voltage is provided by a digital to ana...

Страница 101: ...olled by the DAC so that the phase relationship is that of the measured BIAS information along with the 1pps reference In this way all of the frequencies as well as the time information provided by the clock is disciplined to the GPS reference information Both the integration filtering of the information in the computer as well as the oscillator stability form a very stable system especially when ...

Страница 102: ... connections Swap antenna with a known good one 2 No Power to Antenna S B 5 Vdc on J2 Check continuity of cable 812502 14 Swap Oncore with a known good one 3 DAC Level at Extremes S B 20000 40000 Do a cold reset See Cold Reset in this chapter of the User s Guide 4 No 10 MHz Check 10MHz output from Oscillator 5 Bad Oncore Swap Oncore with a known good one 6 Bad 100015 Main Board Swap 100015 with a ...

Страница 103: ...s Guide 4 Bad 100015 Main Board Swap 100015 with a known good one Contact Symmetricom for repair No Wrong Output J4 J9 1 Wrong or Missing Jumper Check Jumper Configuration on 100015 2 Bad 100015 Main Board Swap 100015 with known good Contact Symmetricom for repair Push Buttons Don t Work 1 Interface Cable Not Connected Check cable 812515 3 for proper seating 2 Bad Switch Swap front panel assembly ...

Страница 104: ...5VDC 12VDC Front Panel Keypad 100015 Main Assembly Option Motherboard 1MHz Sine 5MHz Sine RS 232 I O TRACKING LOCKED 1PPS 10MHz IRIG B AC IRIG B DC 1PPS INPUT AC Power Input 1PPS ref RS 422 I O DAC 10MHz POWER POWER POWER J21 J2 J3 J20 J26 J22 J33 ET6000 Block Diagram PRINTER PORT 1MHz Sine 5MHz Sine Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C 5 13 ...

Страница 105: ...CHAPTER FIVE This Page Intentionally Left Blank 5 14 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 106: ...1 09 HT I 10 012 0A LF J 11 013 0B VT K 12 014 0C FF L 13 015 0D CR M 14 016 0E SO N 15 017 0F SI O 16 020 10 DLE P 17 021 11 DC1 Q 18 022 12 DC2 R 19 023 13 DC3 S 20 024 14 DC4 T 21 025 15 NAK U 22 026 16 SYN V 23 027 17 ETB W 24 030 18 CAN X 25 031 19 EM Y 26 032 1A SUB Z 27 033 1B ESC 28 034 1C FS 29 035 1D GS 30 036 1E RS 31 037 1F US _ Note First denotes the Control Key Symmetricom Inc ET6xxx...

Страница 107: ...8 046 26 39 047 27 40 050 28 41 051 29 42 052 2A 43 053 2B 44 054 2C 45 055 2D 46 056 2E 47 057 2F 48 060 30 0 49 061 31 1 50 062 32 2 51 063 33 3 52 064 34 4 53 065 35 5 54 066 36 6 55 067 37 7 56 070 38 8 57 071 39 9 58 072 3A 59 073 3B 60 074 3C 61 075 3D 62 076 3E 63 077 3F A 2 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 108: ...0 106 46 F 71 107 47 G 72 110 48 H 73 111 49 I 74 112 4A J 75 113 4B K 76 114 4C L 77 115 4D M 78 116 4E N 79 117 4F O 80 120 50 P 81 121 51 Q 82 122 52 R 83 123 53 S 84 124 54 T 85 125 55 U 86 126 56 V 87 127 57 W 88 130 58 X 89 131 59 Y 90 132 5A Z 91 133 5B 92 134 5C 93 135 5D 94 136 5E 95 137 5F _ Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C A 3 ...

Страница 109: ...7 g 104 150 68 h 105 151 69 i 106 152 6A j 107 153 6B k 108 154 6C l 109 155 6D m 110 156 6E n 111 157 6F o 112 160 70 p 113 161 71 q 114 162 72 r 115 163 73 s 116 164 74 t 117 165 75 u 118 166 76 v 119 167 77 w 120 170 77 x 121 171 79 y 122 172 7A z 123 173 7B 124 174 7C 125 175 7D 126 176 7E 127 177 7F DEL A 4 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 110: ...ecision subset of the ephemeris parameters The almanac data is used by the GPS satellite receiver to compute the elevation and azimuth angle of the satellite Each satellite broadcasts the almanacs for all satellites ALT Altitude Anywhere Fix The ability of a receiver to start position calculations without being given an approximate location and appropriate time APPOS Approximate Position ASCII Ame...

Страница 111: ...itter C A Coarse Acquisition code This is the civilian code made available by the DoD It is also known as SPS Standard Positioning Service Channel Refers to the GPS receiver hardware that is required to lock to a satellite make the range measurements and collect data from the satellite Clock Bias The difference between the clock s indicated time and true universal time Control Segment A world wide...

Страница 112: ...See RS 232 C DoD Department of Defense DOP Dilution of Precision Doppler Shift The apparent change in the frequency of a signal caused by the relative motion of the transmitter and receiver DoT Department of Transportation DTE Data Terminal Equipment See RS 232 C E ECEF Earth Centered Earth Fixed EIA Electronic Industries Association Elevation Angle The angle between the line of sight vector and t...

Страница 113: ...uncertainty in range affects the uncertainty in position The GDOP depends on where the satellites are relative to the user A large GDOP means that a small error in range will translate into a large error in position GDOP has two components PDOP Position Dilution of Precision TDOP Time Dilution of Precision Geoid Refers to the actual physical shape of the earth which is hard to describe mathematica...

Страница 114: ... synchronization information for the transfer of tracking from the C A to P code HDOP VDOP HDOP and VDOP are the horizontal and vertical components of the PDOP They describe how an uncertainty in range effects the horizontal position latitude and longitude and the vertical position altitude For 2 D position fixes HDOP is all that counts I ICD Interface Control Document ID Identification I F Interf...

Страница 115: ...h the ionosphere J No glossary terms have been defined for J K No glossary terms have been defined for K L L1 The primary L Band signal radiated by each NAVSTAR satellite at 1575 42 MHz The L1 beacon is modulated with the C A and P codes with the NAV message L2 is centered at 1227 60 LAT Latitude LON Longitude LSB Least Significant Bit B 6 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 116: ...e different paths Usually caused by one path being bounced or reflected N NAV Navigation NAV DATA The 1500 bit navigation message broadcast by each satellite at fifty BPS Bits Per Second on both the L1 and L2 beacons This message contains system time clock correction parameters ionospheric delay model parameters the satellite Ephermeris and health status This information is used to process GPS sig...

Страница 117: ...th GPS based on dual frequency P code PRN Pseudo Random Number p s Picoseconds per second Pseudo Random Code A signal with random noise like proportions It is a very complicated but repeated pattern of ones and zeros Pseudo Range A measure of the range from the GPS receiver antenna to the satellite Pseudo range is obtained by multiplying the speed of light by the apparent transit time of the signa...

Страница 118: ... the elevation drops below the mask RS 232 C An EIA specification S S A Selective Availability Selective availability is essentially a method for artificially creating a significant clock error in the satellites When implemented it is the largest source of error in the GPS system SCH Schedule SEP Spherical Error Probable SPS Standard Positioning Service The normal civilian positioning accuracy obt...

Страница 119: ...ainty in the clock bias TI Time Interval U μs Microsecond USNO United States Naval Observatory UTC Universal Time Coordinated The time standard maintained by the U S Naval Observatory GPS Time is directly related to UTC time V No glossary terms have been defined for V B 10 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 120: ...d a flattening of 1 298 26 WGS 84 Word Geodetic System 1984 A mathematical reference ellipsoid used by GPS having a semi major axis of 6378 137 kilometers and a flattening of 1 298 257223563 X No glossary terms have been defined for X Y No glossary terms have been defined for Y Z No glossary terms have been defined for Z Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C B 11 ...

Страница 121: ...APPENDIX B This Page Intentionally Left Blank B 12 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 122: ...can output any of the following codes IRIG A132 IRIG B122 IRIG G142 IRIG E112 IRIG E122 IRIG H112 IRIG H122 XR3 2137 NASA 36 These modulated codes are generated using the Three Channel Encoder Assembly 55116 Code type selection is remotely selected via the RS 232 I O Port rear panel connector J12 or via the front panel keypad SW4 located on Assembly 55116 plugged into the option area of the Synchr...

Страница 123: ...r inputs a digit 1 to 3 to select the specific channel The user inputs a two digit number to select the code type based on the following table Code Output Selection 00 IRIG A 01 IRIG B 02 IRIG G 03 IRIG E 100 Hz 04 IRIG E 1 kHz 05 IRIG H 100 Hz 06 IRIG H 1 kHz 07 XR3 08 2137 09 NASA 36 The system responds with OK CR LF Example E102 The above example will program Channel 1 of the Three Channel Enco...

Страница 124: ...r To return to the first menu screen press the MENU keyboard switch If local control of this module is desires using the DIP switches the jumper pins located at SW4 must not havae the jumper block shorting the pins Then code output selection is made using DIP switches SW1 SW2 and SW3 located on Assembly 55116 Refer to Table 01 1 on the following page Table 01 1 Modulated Time Code Output Selection...

Страница 125: ...atio and amplitude can be individually adjusted for each of the three channels as follows Table 01 2 Amplitude and Modulation Radio Controls Channel 1 BNC J3 Channel 2 BNC J5 Channel 3 BNC J6 Modulation Ratio R10 R12 R14 Amplitude R11 R13 R15 Detailed definitions and specifications for each of the time codes that are generated by the Three Channel Encoder are provided on the following pages C 4 ET...

Страница 126: ...0 1 seconds Recycles yearly Straight Binary Time of Day CODE WORD 17 binary digits Seconds only Recycles each 24 hours 86399 Code Word Structure BCD Word begins at INDEX COUNT 1 Binary coded elements occur between POSITION IDENTIFIER ELEMENTS seven for seconds seven for minutes six for hours ten for days and four for 0 1 seconds until the CODE WORD is complete A POSITION IDENTIFIER occurs between ...

Страница 127: ...ours 08 Minutes 32 Seconds 0 10 20 P0 PR 1 2 4 8 10 20 40 P1 P2 Binary One 5 mS Binary Zero 2 mS Reference 8 mS 1 2 4 8 10 20 40 Seconds Minutes 30 P3 Hours BCD Time of Year 1 2 4 8 10 20 40 P4 40 80 1 2 4 8 10 20 Days 50 Time Frame 1 Second P5 100 200 Time of Day Straight Binary Seconds Time Frame 1 second Code Digit Weighting Options BCD SB or both Binary Coded Decimal Time of Year CODE WORD 30 ...

Страница 128: ...s REFERENCE MARKER One per second Two consecutive POSITION IDENTIFIERS The on time point to which the CODE WORD refers is the leading edge of the second POSITION IDENTIFIER Resolution 10 milliseconds unmodulated One millisecond modulated Carrier Frequency 1kHz when modulated 1 3 3 IRIG FORMAT G Time Frame 0 01 Second 50 60 70 P5 P6 P7 1 2 4 8 0 01 Sec 100µS Element Rate 10 KPPS 80 90 P8 P9 Control...

Страница 129: ...onal seconds information which occurs following the Day of Year information Element Rates Available 10000 per second basic element rate 1000 per second POSITION IDENTIFIER rate 100 per second frame rate Element Identification On Time reference point for each element is its leading edge INDEX MARKER duration 0 02 milliseconds Binary Zero or uncoded Element CODE DIGIT duration 0 05 milliseconds Bina...

Страница 130: ... Binary coded elements occur between POSITION IDENTIFIER ELEMENTS three for seconds seven for minutes six for hours ten for days until the CODE WORD is complete A POSITION IDENTIFIER occurs between decimal digits in each group to provide separation for visual resolution Least Significant Digit Occurs first Element Rates Available 10 per second basic element rate One per second POSITION IDENTIFIER ...

Страница 131: ...ts Minutes hours and days Recycles yearly Code Word Structure BCD Word begins at INDEX COUNT 10 Binary coded elements occur between POSITION IDENTIFIER ELEMENTS seven for minutes six for hours ten for days until the CODE WORD is complete A POSITION IDENTIFIER occurs between decimal digits in each group to provide separation for visual resolution Least Significant Digit Occurs first Element Rates A...

Страница 132: ...20 160 200 240 280 320 360 400 800 mS 440 480 520 560 600 640 680 720 760 800 840 880 920 960 0 200 mS Time Frame 1 Second Time Frame One second Code Digit Weighting Options BCD Binary Coded Decimal Time of Year CODE WORD 20 binary digits Hours minutes and seconds Recycles every 24 hours Code Word Structure BCD Word begins at INDEX COUNT 1 Binary coded elements occur between POSITION IDENTIFIER EL...

Страница 133: ...0 280 320 360 400 800 mS 440 480 520 560 600 640 680 720 760 800 840 880 920 960 0 200 mS Time Frame 1 Second Time Frame One second Code Digit Weighting Options BCD Binary Coded Decimal Time of Year CODE WORD 20 binary digits Hours minutes and seconds Recycles every 24 hours Code Word Structure BCD Word begins at INDEX COUNT 1 Binary coded elements occur between POSITION IDENTIFIER ELEMENTS six fo...

Страница 134: ...reds of Days 50 40 30 10 20 40 1 2 4 8 Tens of Minutes Units of Hours Time Frame 1 Second 10 20 Tens of Seconds Units of Minutes 1 2 4 8 0 Units of Seconds 8 4 2 1 10 20 40 Binary One 6 mS Binary Zero 2 mS Reference 6 mS Time Frame One second Code Digit Weighting Options BCD Binary Coded Decimal Time of Year CODE WORD 30 binary digits Seconds minutes hours and days Recycles yearly Code Word Struct...

Страница 135: ... POSITION IDENTIFIER duration Six milliseconds REFERENCE MARKER Five consecutive POSITION IDENTIFIERS followed by an INDEX MARKER The on time point to which the CODE WORD refers is the leading edge of the INDEX MARKER following the four POSITION IDENTIFIERS Resolution 10 milliseconds unmodulated One millisecond modulated Carrier Frequency 1kHz when modulated C 14 ET6xxx ExacTime GPS TC FG Rev C Sy...

Страница 136: ...OPTION DESCRIPTIONS ASSEMBLY 55116 Symmetricom Inc ET6 ExacTime GPS TC FG Rev C C 15 ...

Страница 137: ...10 dBc Hz 100Hz 112 dBc Hz 1KHz 114 dBc Hz 10KHz 120 dBc Hz 100KHz 120 dBc Hz 1 2 FUNCTIONAL EXPLANATION A 1 MHz square wave derived from the 10MHz internal oscillator is input to J1 pin 7 of the Sine Wave Shaper Assembly The signal is filtered and shaped to generate the 1 MHz Sine Wave output at P1 pin 2 of the same assembly This signal is then routed to a rear panel BNC Refer to the GPS Option C...

Страница 138: ...Hz 100Hz 112 dBc Hz 1KHz 114 dBc Hz 10KHz 116 dBc Hz 100KHz 119 dBc Hz 1 2 FUNCTIONAL EXPLANATION A 5 MHz square wave derived from the 10MHz internal oscillator is input to J1 pin 7 of the Sine Wave Shaper Assembly The signal is filtered and shaped to generate the 5 MHz Sine Wave output at P1 pin 2 of the same assembly This signal is then routed to a rear panel BNC Refer to the GPS Option Connecto...

Страница 139: ...bridge rectifiers the individual input pins are not polarity sensitive Because the outputs of the two bridge rectifiers are connected together to form the input to the DC DC converter which ever input is the higher DC voltage will power the unit If the higher DC input is lost or not present the other DC input will power the unit 1 2 SPECIFICATIONS Input Voltage Current 10VDC to 37VDC Approximately...

Страница 140: ...Input 1 J1A pin 1 DC Input 1 J1A pin 2 Chassis Ground J1A pin 3 DC Input 1 Return Signal Ground Input 2 J1B pin 1 DC Input 2 J1B pin 2 Chassis Ground J1B pin 3 DC Input 2 Return Signal Ground o o o Pin 1 Symmetricom Inc ET6 ExacTime GPS TC FG Rev C C 19 ...

Страница 141: ...APPENDIX C ASSEMBLY 100002 C 20 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 142: ... Figure One C C Pin Assignments TB1 1 48V INPUT A TB1 2 Return INPUT A TB1 3 Chassis Ground TB1 4 Chassis Ground TB1 5 Return INPUT B TB1 6 48V INPUT B 1 1 SPECIFICATIONS DC Input Voltage Range DC 38 73 VDC DC Input Current Max 38V 6 amps DC Input Current Max 73V 3 amps Note The input current is dependent on the number of options installed in the GPS TC FG Internal Voltages Generated 5V 12V 12V Ma...

Страница 143: ...the higher voltage will be used to power the unit Even though the inputs are labeled and it really doesn t matter how they are connected The labeling is to eliminate confusion Both inputs have 1 amp normal blow fuses for protection 1 3 TEMPERATURE The operating temperature of the unit should not exceed 40 C This limitation is due to the fact that there is no forced air flow over the DC DC converte...

Страница 144: ...from Assembly 55187 are from a rear panel terminal strip TB1 All input outputs have metal oxide varistors for transient voltage suppression The pin assignments for TB1 are shown below as viewed from the rear of the unit Figure One TB1 1 TB1 12 Pin Assignments TB1 1 DC In 1 TB1 2 DC In 1 Return TB1 3 Chassis Ground TB1 4 Fault Relay Common Contact TB1 5 Fault Relay Normally Closed Contact TB1 6 Tim...

Страница 145: ...lay output on the rear panel terminal strip TB1 6 and 7 provides a contact closure until the unit has achieved oscillator lock For example until the front panel LOCKED LED illuminates Operation of the optional 50 60Hz measurement feature is as follows With the unit operating connect the AC measurement source to TB1 8 and TB1 9 50 60Hz Measurement Input Make sure that when plugging in the cable to ...

Страница 146: ...econds Pushing the number four key will stop the measurement and OFF will appear on the LCD display in the lower right hand corner Pushing the number five key will start the measurement and ON will appear after the 5 If the unit is not locked ERR will appear in the lower right hand corner of the LCD display Pushing the number six key of the keypad selects either 50Hz or 60Hz 50Hz or 60Hz selection...

Страница 147: ...option is OFF If a time offset is entered while the 50 60Hz option is enabled the message OPT ON will be sent and the time offset data is ignored The offset is stored in battery backed RAM so it will be retained if the unit is turned OFF and then back ON again 1 6 REQUEST 50 60Hz MEASUREMENT DATA This command allows the user to obtain the 50 60Hz measurement data The user enters A HEX 24 HEX 41 Th...

Страница 148: ...e up in the OFF default mode If the 50 60Hz option is turned on prior to the unit achieving LOCK ON will be replaced by ERR and measurement data will not be available When measuring the 60Hz with a time period of 16 66 milliseconds if a measurement occurs outside a one millisecond window of that time period such as a noise spike the measurement is ignored and an error is counted If 1 000 successiv...

Страница 149: ...ge 0 to 6 Volts Mechanical Frequency Adjust 1PPM minimum 3PPM maximum The following specifications apply to the Selected 10 MHz Output at a 13dbm output level Harmonics 35 dBc Spurious Noise 35 dBc Phase Noise 1Hz 85 dBc Hz 10Hz 113 dBc Hz 100Hz 134 dBc Hz 1KHz 144 dBc Hz 10KHz 148 dBc Hz It is recommended that the oscillator be nulled when the DAC value starts to approach either extreme of 5 000 ...

Страница 150: ... Refer to Chapter Four Enable Disciplining in the User s Guide 7 After approximately one hour check the DAC value number again If it has changed by more than 5000 from 32767 repeat steps two through six 1 3 CALIBRATION SECOND METHOD If a known frequency standard is not available the oscillator may be nulled as follows 1 Set the unit to operate in the single satellite 1SV mode Make sure the unit is...

Страница 151: ...cillator in the appropriate direction until the DAC value is approximately at its midpoint 32767 7 Install the screw in the oscillator adjustment access hole 8 If after approximately one hour the DAC value has changed by more than 5 000 from 32767 repeat steps one through six C 30 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 152: ...a 50 pin 3M ribbon type connector 1 1 1 OUTPUT CHARACTERISTICS All outputs are positive true logic except where noted HCMOS compatible Each output capable of sinking and sourcing four milliamperes 1 1 2 MATING CONNECTOR The suggested mating connector is 3M manufacturer s Part Number 3425 6000 or 3425 6050 or equivalent 1 1 3 PIN ASSIGNMENTS See Table One Two sample time pulses are provided in the ...

Страница 153: ...ning of the ExacTime User s Guide accompanying this Option Description 1 2 OPERATION This operation applies only to the three optional pulse rate outputs For the purposes of this Option Description Channel One equates to Output One Channel Two equates to Output Two and Channel Three equates to Output Three The three selectable pulse rate outputs can be programmed to provide the following rates 1 1...

Страница 154: ...channel output select 0 Channel One 1 Channel Two 3 Channel Three The next two digits are a code to select the pulse rate 01 1pps 02 10pps 03 2400pps The last three digits are required for a complete command but any digit can be entered because they aren t used Example F103XXX The above example indicates the user selecting Channel Two to have a pulse rate of 2400pps The unit responds with OK CR LF...

Страница 155: ...s Pin Signal Pin Signal 1 mS1 26 D20 2 M40 27 S2 3 mS2 28 D40 4 H1 29 S4 5 mS4 30 D80 6 H2 31 S8 7 mS8 32 D100 8 H4 33 S10 9 mS10 34 D200 10 H8 35 S20 11 mS20 36 GND 12 H10 37 S40 13 mS40 38 ST1P 14 H20 39 M1 15 mS80 40 GND 16 D1 41 M2 17 mS100 42 N U 18 D2 43 M4 19 mS200 44 UNLOCKED 20 D4 45 M8 21 mS400 46 GND 22 D8 47 M10 23 mS800 48 ST1K 24 D10 49 M20 25 S1 50 GND True when unit is unlocked Low...

Страница 156: ...OPTION DESCRIPTIONS ASSEMBLY 55128 Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 35 ...

Страница 157: ...rear panel connector J13 Refer to the GPS Option Connection Configuration sheet in the User s Guide 1 2 OPERATION The first step in using the IEEE 488 I O port is to program select the Device Address The current IEEE 488 address may be found by pressing the front panel MENU keypad switch until the IEEE 488 screen as shown below is displayed on the LCD display 1 IEEE488 ADDR 17 If desired the addre...

Страница 158: ...plicable Note With the exception of UNL MTA and lAG the protocol is identical to that of the RS 232 I O When communicating to the 488 interface if more than 30 seconds elapses between commands the I O will time out and the communication will have to be repeated If after talking to our interface it is necessary to receive some data send the following commands mnemonics UNL unlisten MLA my listen ad...

Страница 159: ...r Pin Assignment J13 Pin Signal 1 D101 2 D102 3 D103 4 D104 5 EOI 6 DAV 7 NRFD 8 NDAC 9 IFC 10 SRQ 11 ATN 12 GND 13 D105 14 D106 15 D107 16 D108 17 REN 18 GND 19 GND 20 GND 21 GND 22 GND 23 GND 24 GND C 38 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 160: ...lect Mode User s Guide s 73 Enable Time Interval User s Guide t 74 Disable Time Interval User s Guide u 75 Request Time Interval User s Guide x 78 Request Mask Levels User s Guide y 79 Enter Mask Levels User s Guide z 7A Enable Discipline User s Guide 7B Disable Discipline User s Guide 7D Enter Position User s Guide 7E Enter DAC Value User s Guide DEL 7F Request DAC Value User s Guide P 50 Select ...

Страница 161: ... Note 3 Opt Des 08AE B 42 Set up External 50 60 Hz Measurement See Note 3 Opt Des 08AE C 43 Enter IEEE 488 Address This Opt Des Note 1 Single or Triple Event Log Option Option 04 or 05 must be installed See GPS Option Description 04 or 05 Note 2 Preset Coincidence Option 09 must be installed See GPS Option Description 09 Note 3 115VAC 125VDC Power Supply with 50 60Hz Measurement Option Option 08AE...

Страница 162: ...OPTION DESCRIPTIONS ASSEMBLY 55115 Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 41 ...

Страница 163: ...Assembly 812503 12 which is used to interface between J20 of the 35002 GPS Main Assembly and J1 of the 55189 Power Entry and Alarm Relays Assembly is also provided The signal connections provided between J20 of the GPS Main Assembly and J2 of the 55189 Power Entry and Alarm Relays Assembly are as follows J20 PIN J2 PIN SIGNAL 1 1 LOCK 2 2 TRK 3 3 OUT5 4 4 OUT6 5 5 PD0 6 6 EXTFRE Q 7 7 PD7 8 8 VDD ...

Страница 164: ...requency standard with an oscilloscope or other suitable means by using the following steps 1 Turn on the unit and wait approximately one hour for the oscillator to warm up and stabilize 2 Sync one trace of an oscilloscope on the known frequency standard Using the other trace monitor the 10MHz output of the unit 3 The input of the DAC must be held static prior to the nulling oscillator This can be...

Страница 165: ...play 3 The oscillator is located in front of the GPS Main Board on the Chassis Assembly 4 SLOWLY no more than 45o each time adjust the oscillator and watch the DAC value change If the DAC value is 65535 turn the oscillator adjustment counterclockwise which will decrease the frequency and the DAC value If the DAC value is 00000 turn the oscillator adjustment clockwise which will increase the freque...

Страница 166: ...locked to the GPS corrected 1PPS The signal connections provided between the X72 connector and connector J23 on the GPS Main board are as follows J23 PIN SIGNAL 1 VDD Power Input 2 VDD 3 VDD 4 VDD 5 VDD 6 VDD 7 VDD 8 SERVICE 9 DOUT 10 DIN 11 FREQ CTRL 12 VSS Power and Signal Return 13 VSS 14 VSS 15 VSS 16 VSS 17 VSS 18 VSS 19 1PPS IN 20 1PPS OUT 21 LOCK if low Rb oscillator locked 22 FXQ VCXO freq...

Страница 167: ...ture 40o C Base Plate to 85o C Base Plate Storage Temperature 55o C to 100o C Supply Voltage 5VDC 10 Warm up Time 5 minutes to lock accuracy lock 5 x 10 8 7 5 minutes accuracy 1 x 10 9 The following specifications apply to the Selected 10 MHz Output from the ET6000 etc at a 13dbm output level Harmonics 37 dBc Spurious Noise 70 dBc Phase Noise 1Hz 76 dBc Hz 10Hz 91 dBc Hz 100Hz 131 dBc Hz 1KHz 144 ...

Страница 168: ... 100Hz 112 dBc Hz 1KHz 115 dBc Hz 10KHz 117 dBc Hz 100KHz 121 dBc Hz 1 2 FUNCTIONAL EXPLANATION A 10MHz square wave derived from the 10MHz internal oscillator is input to J1 pin 9 of the Sine Wave Shaper Assembly The signal is filtered and shaped to generate the 10MHz Sine Wave output at P1 pin 2 of the same assembly This signal is then routed to a rear panel BNC Refer to the GPS Option Connector ...

Страница 169: ...oot length of 9913 Antenna Cable and the 23B option comes with a fifty foot length of 9913 Antenna Cable Both cables have Type N positive connectors on each end This Option may require that the GPS unit to which it is connected have a Bias T Assembly installed externally This assembly would furnish a separate 5 volts to power the antenna See the Bias T installation procedure furnished with the Bia...

Страница 170: ... on the unprotected side The connection between the mounting plate and the ground terminal should be accomplished with a low resistance path such as a copper strap customer furnished The contact surface of the mounting plate must be conductive free of any paint anodization or oxides Tighten the mounting nut to reduce the contact resistance between the arrestor body and the mounting plate Connect a...

Страница 171: ...nstallation of the Lightning Arrestor Disconnect or switch off in line equipment when installing or inspecting the Lightning Arrestor Also do not install or inspect the Lightning Arrestor during an electrical storm When connecting the Lightning Arrestor or when changing the gas capsule arrestor make sure that the connecting equipment and components are disconnected or switched off ET6xxx ExacTime ...

Страница 172: ...tning Arrestor 3403 17 0016 Inside Outside Ground Terminal 1 4 Ground Terminal 1 4 Access to Non radioactive Gas Capsule Arrestor 73 Z 0 0 448 Copper Ground Strap Customer Furnished Mounting Plate Customer Furnished To GPS Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 51 ...

Страница 173: ... Mounting Hole 0 1732 4 4 Mounting Hole 0 1732 4 4 2 1654 55 2 5129 64 ANTENNA EQUIPMENT Clearance Hole On Mounting Plate 0 625 16 4 1339 105 4 5276 115 0 3346 8 5 Max 1 122 28 5 NOTE Number in is Millimeters ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 52 ...

Страница 174: ...n Connector Configuration sheet located at the front of the ExacTime User s Guide The type of module plugged into each socket depends on the jumper selected input Analog buffers can output both digital and analog signals For digital signals requiring specific pulse widths and on time edges digital buffers are required The typical module input selection for U1 is as follows U1A 1 to U1A 28 1MHz Squ...

Страница 175: ... input amplitude Its frequency response is from DC to 10MHz 1 4 GPS Option 27C RS 422 Differential Buffer Assembly 35028 This RS 422 buffer plug in module is a differential line driver with output levels of 0 to 5 volts It is a line driver for digital data transmission over balanced lines It is designed to provide unipolar differential drive to twisted pair or parallel wire transmission lines 1 5 ...

Страница 176: ...OPTION DESCRIPTIONS ASSEMBLY 55143 Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 55 ...

Страница 177: ... determines the rear panel output BNC The following is the correlation between the option area and the output Option Area Rear Panel BNC J7 J9 J3B J8 J10 J3C J18 J22 J3E J19 J23 J3F The buffered output can provide TTL levels into 50Ω 1 2 OPTIONAL FEATURES The following features are switch selectable S1 open up Selects T1 1 544MHz output S1 closed down Selects E1 2 048MHz output S2 open up Allows t...

Страница 178: ...f the ExacTime User s Guide For a more in depth description of T1 and or E1 and the options provided on this assembly refer to the following CCITT Standards G 704 G 706 and G 732 Also ATT pub 43801 ATT C B 142 and ATT C B 144 1 1 GENERAL DESCRIPTION GENERATION OF T1 1 544MHz Assembly 55155 generates the T1 1 544MHz framed all ones DS1 signal It provides the following output to the rear panel of th...

Страница 179: ...le Two below 3 5 Inhibit Bit 7 Stuffing Enable Bit 7 Stuffing 3 6 Inhibit B8ZS Enable B8ZS The normal as shipped position of each switch TABLE TWO LINE LENGTH SELECTION SW3 4 SW3 3 SW3 2 Option Selected Application 0 0 0 Test Mode Do Not Use 0 0 1 7 5 dB Build out T1 CSU 0 1 0 15 dB Build out T1 CSU 0 1 1 0 dB Build out 0 133 feet T1 CSU DSX 1 Cross Connect 1 0 0 133 266 Feet DSX 1 Cross Connect 1...

Страница 180: ...ame M 1 Frame Bit No F Frame Bit 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 D4 Format 0 0 0 1 1 0 1 1 1 0 0 1 0 0 0 1 M Multi frame M Multi Frame Frame No 21 22 23 24 1 2 3 4 5 6 7 8 11 12 13 14 15 16 17 18 19 20 1 2 3 4 5 6 7 8 9 10 M M 1 0 0 1 1 0 1 0 0 Frame Bits Multi frame Multi frame Frame No FDL bits are all zeros Appropriate CRC check sums are generated Extended Superframe Format Frame Format Figu...

Страница 181: ... all ones CEPT Hi 2 Balanced 2 048MHz framed all ones CEPT Lo 3 Output Transformer Center Tap Adding a jumper from E3 to E4 on the 55155 assembly allows the transformer center tap to be grounded The output is frequency locked to an internal 10MHz reference The CEPT signal is switch selectable to provide various features See Table Four Down is the closed 0 position Up is the open 1 position Switch ...

Страница 182: ... CAS Signaling One 2 3 Transmit National International Zero Transmit National International One 2 4 Disable Remote Alarm Enable Remote Alarm 2 5 Disable Distant Multi Frame Alarm Enable Distant Multi Frame Alarm 2 6 AMI Coding HDB3 Coding 3 1 T1 Output E1 Output 3 2 3 3 3 4 3 5 Disable CRC4 Multi frame Enable CRC4 Multi frame 3 6 Enable CAS Multi frame Disable CAS Multi frame The normal as shipped...

Страница 183: ...rame M Multi Frame M 1 Time Slot Format 8 Bits Time Slot 1 2 3 4 5 6 7 8 1 2 3 4 Bit Number Time Slot M Time Slot M 1 Frame Format Thirty Two Time Slots Frame Time Slot Number 0 1 2 3 30 31 29 0 1 2 3 4 Frame M 1 Frame M Table Five is a list of specifications applicable to GPS Option 33C E1 Assembly 55155 1 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 62 ...

Страница 184: ... 55155 1 Outputs CEPT Signal Type CEPT Balanced Frequency 2 048 MHz Format Framed All 1 s Jitter 0 05 U I Connector See Note Note See the GPS Option Connector Sheet in the ExacTime User s Guide Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 63 ...

Страница 185: ...APPENDIX C ASSEMBLY 55155 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 64 ...

Страница 186: ...the ExacTime User s Guide For a more in depth description of T1 and or E1 and the options provided on this assembly refer to the following CCITT Standards G 704 G 706 and G 732 Also ATT pub 43801 ATT C B 142 and ATT C B 144 1 1 GENERAL DESCRIPTION GENERATION OF T1 1 544MHz Assembly 55155 2 generates the T1 1 544MHz framed all ones DS1 signal and associated outputs It provides the following input o...

Страница 187: ...p is the open 1 position Switch 1 1 selects between T1 and E1 functions TABLE ONE Switch Closed 0 Open 1 1 1 Selects E1 Selects T1 1 2 Inhibits 1pps Sync Enables 1pps Sync 1 3 Allows framed output during alarms Inhibits framed output during alarms 2 1 N A N A 2 2 ABCD Data Zero ABCD Data One 2 3 Transmit Link Data Zeros Transmit Link Data Ones 2 4 Internally Generate S Bit Insert transmit link dat...

Страница 188: ...h Table Three is a list of specifications applicable to GPS Option 33D T1 Assembly 55155 2 TABLE THREE SPECIFICATIONS 55155 2 Outputs DS1 Signal Type DS1 Balanced Frequency 1 544 MHz Format Framed All 1 s D4 or ESF Jitter 0 05 U I Connector See Note Frame Marker Signal Type TTL Frequency 8 kHz Connector See Note TTL Clock Signal Type TTL Frequency 1 544 MHz Connector See Note Inputs Frame Synchron...

Страница 189: ... 1 1 0 1 1 1 0 0 1 0 0 0 1 M Multi frame M Multi Frame Frame No 21 22 23 24 1 2 3 4 5 6 7 8 11 12 13 14 15 16 17 18 19 20 1 2 3 4 5 6 7 8 9 10 M M 1 0 0 1 1 0 1 0 0 Frame Bits Multi frame Multi frame Frame No FDL bits are all zeros Appropriate CRC check sums are generated Extended Superframe Format Frame Format Figure One D4 and Extended Superframe Formats ET6xxx ExacTime GPS TC FG Rev C Symmetric...

Страница 190: ...mon Contact 9 Alarm Relay Normally Closed Contact 10 Not Used 11 SYNC Input 12 SYNC Input Return GND 13 8kHz TTL Output 14 GND 15 2 048Mhz TTL Clock Output 16 GND 17 Not Used 18 Not Used 19 Not Used 20 Not Used SYNC input allows the CEPT and frame alignment outputs to be synchronized to an external reference of 8kHz or sub multiple of 8kHz Alarm relay closure is a summary alarm closure Adding a ju...

Страница 191: ... CAS Signaling Zero CAS Signaling One 2 3 Transmit National International Zero Transmit National International One 2 4 Disable Remote Alarm Enable Remote Alarm 2 5 Disable Distant Multi Frame Alarm Enable Distant Multi Frame Alarm 2 6 AMI Coding HDB3 Coding 3 1 T1 Output E1 Output 3 2 3 3 3 4 3 5 Disable CRC4 Multi frame Enable CRC4 Multi frame 3 6 Enable CAS Multi frame Disable CAS Multi frame Th...

Страница 192: ...tor See Note TTL Clock Signal Type TTL Frequency 1 544 MHz Connector See Note Inputs Frame Synchronization TTL compatible active low Frequency 8 kHz or sub multiple of 8 kHz Connector See Note Monitor Summary Alarm Contact Closure Contact Rating maximum 2 A at 30 V dc Connector See Note Note See the GPS Option Connector Configuration Sheet in the ExacTime User s Guide Symmetricom Inc ET6xxx ExacTi...

Страница 193: ...er Multi Frame M Multi Frame M 1 Time Slot Format 8 Bits Time Slot 1 2 3 4 5 6 7 8 1 2 3 4 Bit Number Time Slot M Time Slot M 1 Frame Format Thirty Two Time Slots Frame Time Slot Number 0 1 2 3 30 31 29 0 1 2 3 4 Frame M 1 Frame M Note For a top assembly view of this module see the previous section ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 72 ...

Страница 194: ...ly to J1 of the 55189 Power Entry and Alarm Relays Assembly It provides the signal paths to and from the 55189 Assembly to the GPS Main Assembly 35002 1 1 OPERATIONAL FEATURES The basic Motherboard has four plug in option areas J7 J9 J8 J10 J18 J22 and J19 J23 Each of these option areas provides one or two single ended BNC outputs However depending upon the option installed some of these outputs m...

Страница 195: ...40P the signal connections provided at J2 of the 35007 Motherboard Assembly are as follows J2 PIN SIGNAL 1 LOCK 2 TRK 3 OUT5 4 OUT6 5 PD0 6 EXTFREQ 7 PD7 8 VDD 5 9 PD6 10 GND ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 74 ...

Страница 196: ...ly to J1 of the 55189 Power Entry and Alarm Relays Assembly It provides the signal paths to and from the 55189 Assembly to the GPS Main Assembly 35002 1 1 OPERATIONAL FEATURES The basic motherboard has four plug in option areas J7 J9 J8 J10 J18 J22 and J19 J23 Each of these option areas provides one or two single ended BNC outputs However depending upon the option installed some of these outputs m...

Страница 197: ...40AP the signal connections provided at J2 of the 35007 Motherboard Assembly are as follows J2 PIN SIGNAL 1 LOCK 2 TRK 3 OUT5 4 OUT6 5 PD0 6 EXTFREQ 7 PD7 8 VDD 5 9 PD6 10 GND ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 76 ...

Страница 198: ...J2 of the 35007 Motherboard Assembly to J1 of the 55189 Power Entry and Alarm Relays Assembly It provides the signal paths to and from the 55189 Assembly to the GPS Main Assembly 35002 1 1 OPERATIONAL FEATURES The basic motherboard has four plug in option areas J7 J9 J8 J10 J18 J22 and J19 J23 Each of these option areas provides one or two single ended BNC outputs However depending upon the option...

Страница 199: ...a a 250 milliamphere high speed buffer driver The gain of the buffer is 1 1 so the output amplitude is dependent on the input and the load For GPS Option 40BP the signal connections provided at J2 of the 35007 Motherboard Assembly are as follows J2 PIN SIGNAL 1 LOCK 2 TRK 3 OUT5 4 OUT6 5 PD0 6 EXTFREQ 7 PD7 8 VDD 5 9 PD6 10 GND ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 78 ...

Страница 200: ...te Array U1 which is programmed configured by PROM Programmable Read Only Memory U2 at initial power on These pulse rates are buffered by Buffer Driver U3 and output on SMB connectors J2 J3 and J4 or input directly to the Motherboard and output on its BNC connectors Table 1 below shows the relationship of the 3 pulse rate outputs and their respective output connectors TABLE 1 PULSE RATE OUTPUT ASS...

Страница 201: ... Switch Position Output Pulse Rate 1 2 3 4 5 Closed Closed Closed Closed Open 1PPS Open Closed Closed Closed Open 5PPS Closed Open Closed Closed Open 10PPS Open Open Closed Closed Open 20PPS Closed Closed Open Closed Open 30PPS Open Closed Open Closed Open 40PPS Closed Open Open Closed Open 50PPS Open Open Open Closed Open 60PPS Closed Closed Closed Open Open 80PPS Open Closed Closed Open Open 90P...

Страница 202: ...OPTION DESCRIPTIONS ASSEMBLY 100001 Symmetricom Inc ET6xxx ExacTime GPS TC FG Rev C C 81 ...

Страница 203: ...APPENDIX C This Page Intentionally Left Blank ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc C 82 ...

Страница 204: ... connector The Antenna Kit can be ordered with optional cable lengths and accessories Please note the following when setting up longer cable runs Using Belden 9104 the maximum cable length without amplification is 150 feet Using Belden 9104 the maximum cable length using the optional in line amplifier is 300 feet For cable runs longer than 300 feet an optional GPS Down Up Converter kit is availabl...

Страница 205: ...APPENDIX D This Page Intentionally Left Blank A 2 ET6xxx ExacTime GPS TC FG Rev C Symmetricom Inc ...

Страница 206: ... symmetricom com www symmetricom com For more information about the complete range of Quality Timing Products from the Symmetricom group of companies call 1 800 544 0233 in the US and Canada Or visit our site on the world wide web at http www Symmetricom com for continuously updated product specifications news and information ...

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