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CHAPTER FOUR

4-2

bc620/627AT Time and Frequency Processor

Symmetricom, Inc.

MODE 0

TIME CODE DECODING MODE

The TFP uses an input time code as the timing reference. The following codes are supported
(see packet “H”): IRIG A, and B; 2137, XR3; and NASA36. Both modulated carrier and DC
level shift formats are supported (DC level shift is not supported for 2137 or XR3 codes). The
TFP locks its crystal oscillator to the input code rate. The oscillator has a control range of +/- 30
PPM for the standard VCXO version, and ± 2 PPM for the optional oven (OCXO) version. If
the input code is outside these limits the TFP will exhibit periodic slips (i.e., if the TFP reference
deviates from the input source by more than ± 1 millisecond a forced jamsync is performed). If
the input code is lost or removed the TFP will continue to “flywheel” at the last known code rate.
Typical accuracy is less than five parts in 10E7 (two milliseconds of drift per hour).

MODE 1

FREE RUNNING MODE

This mode is virtually the same as mode 2. Without a 1pps input the TFP runs at the last known
oscillator frequency. Major time can be set with the “B” packet. The TFP time base can be
adjusted with packet “D.”

MODE 2

EXTERNAL 1PPS MODE

The TFP synchronizes to the external 1pps input signal. Major time can be loaded with the “B”
packet. The acquisition range is the same as described in mode 0.

MODE 2 is used when a primary time standard such as a GPS receiver is available. In this case
the 1pps output of the standard is input to the TFP.

MODE 3

REAL TIME CLOCK MODE

The TFP synchronizes to a 1pps signal from the on-board real time clock (RTC) IC, and the
major time is also derived from the clock IC. The RTC is battery backed. This mode is not
recommended when using the oven oscillator because the accuracy of the RTC is not high
enough to ensure that the oven will be able to track it with slippage. See Mode 0 description.

MODE 4

GPS MODE (bc627AT GPS Satellite Receiver)

This optional mode is discussed in the bc627AT GPS Satellite Receiver Addendum User’s
Guide.

The bc620.c file has an example function, mode(), which sets the TFP operational mode as
described above.

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Содержание 627AT

Страница 1: ...l service in house repair center WE BUY USED EQUIPMENT Sell your excess underutilized and idle used equipment We also offer credit for buy backs and trade ins www artisantg com WeBuyEquipment REMOTE INSPECTION Remotely inspect equipment before purchasing with our interactive website at www instraview com LOOKING FOR MORE INFORMATION Visit us on the web at www artisantg com for more information on ...

Страница 2: ...bc620 627AT Time and Frequency Processor Revision B User s Guide 8500 0011 March 2004 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 3: ... instructions it may cause interference to radio or television reception If this equipment does cause interference to radio or television reception which can be determined by turning the equipment on and off the user is encouraged to correct the interference by one or more of the following measures Reorient the radio television receiving antenna Move the antenna leads away from any wire runs to th...

Страница 4: ...put 1 5 1 3 7 Environmental Specifications 1 5 1 3 8 Digital Synchronization Signals 1 5 CHAPTER TWO INSTALLATION AND SETUP 2 0 General 2 1 2 1 Base Address Selection 2 1 2 2 Installation Procedure 2 4 2 3 Demonstration Programs 2 5 2 4 MS DOS Device Driver 2 5 CHAPTER THREE SOFTWARE INTERFACE 3 0 General 3 1 3 0 1 Glossary of Key Terms 3 1 3 1 Registers 3 2 3 1 1 PAGE Select Register 3 2 3 1 2 TI...

Страница 5: ...O DATA PACKETS 4 0 General 4 1 4 1 Writing Data Packets 4 1 4 1 1 Packet A Select Operational Mode 4 1 4 1 2 Packet B Set Major Time 4 2 4 1 3 Packet C Command Input 4 4 4 1 4 Packet D Load the D A Converter 4 4 4 1 5 Packet F Heartbeat Periodics Control 4 5 4 1 6 Packet G Propagation Delay Offset Control 4 7 4 1 7 Packet H Set Time Code Format for Mode 0 4 8 4 1 8 Packet I Clock Source Select 4 9...

Страница 6: ...and the Major Time 5 2 5 5 Select Mode 0 IRIG B and Advance TFP 2 5 Milliseconds 5 3 CHAPTER SIX INPUT AND OUTPUT SIGNALS 6 0 General 6 1 6 1 Connector I O 6 1 6 2 Jumper Selections 6 2 CHAPTER SEVEN ADJUSTMENTS 7 0 General 7 1 7 1 Time Code Phase Lock Loop Adjustment 7 1 7 2 Time Code Output Amplitude Adjustment 7 2 APPENDIX A IRIG TIME CODE FORMAT A 0 General A 1 Artisan Technology Group Quality...

Страница 7: ...ABLE OF CONTENTS iv bc620 627AT Time and Frequency Processor Symmetricom Inc This Page Intentionally Left Blank Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 8: ...ers which latch the current time upon host request Event logging days through 0 1 microseconds This feature is implemented with a second set of hardware registers Time is captured on a positive or negative input edge or secondary bus time request Four operational modes are supported Modes are distinguished by the reference source Mode Source Of Synchronization 0 Time code IRIG A IRIG B XR3 2137 NA...

Страница 9: ...cond mode programmable to milliseconds Five maskable interrupt sources are supported IRQ levels 3 7 9 12 14 and 15 can be selected via jumper JP1 Interrupt Source of Interrupt 0 External event input has occurred 1 A periodic output has occurred 2 The time coincidence strobe has occurred 3 A one second epoch 1pps output has occurred 4 An output FIFO data packet is available 1 2 PHYSICAL AND FUNCTIO...

Страница 10: ... U29 C53 C19 RV1 RV2 J3 U23 C39 U24 C41 R20 U25 Q1 Q2 R23 R22 R21 R25 R24 C44 B1 C28 U17 SW1 C21 C20 C23 C22 C25 C24 U20 C30 U18 C20 R9 R8 R10 C31 U21 C37 C33 U19 C32 C34 C35 R12 R11 R15 R16 R17 U22 CR1 CR2 R26 R27 R28 R29 R30 R31 2 4 JP2 R32 R33 U27 U26 C45 1 3 5 7 9 11 13 15 17 19 21 23 R15 R14 R12 R11 R10 R9 R7 R6 R5 R4 R3 JP1 On IRQ C43 C42 Y2 C40 SN C46 C47 C49 J1 J2 TD1 C38 R18 R19 C48 U14 U...

Страница 11: ...Output Amplitude 0 to 0 volts peak to peak Dc Level Shift TTL CMOS compatible 1 3 3 BUS CHARACTERISTICS Address Space 16 bytes in PC I O Address Space 0x100 0x3FF Data Transfer D08 eight bit Interrupts IRQ 3 4 5 6 7 9 10 11 12 14 and 15 jumper selectable Power 5 450 milliamperes 12 20 milliamps 12 55 milliamps 250 milliamps bc627AT 1 3 4 DIGITAL INPUTS Event Capture TTL CMOS positive or negative e...

Страница 12: ... 6 EXTERNAL 10 MHz INPUT Digital Input or TTL CMOS 45 to 55 duty cycle 10MHz Input 1 5 to 4 volts peak to peak 1 3 7 ENVIRONMENTAL SPECIFICATIONS Temperature Operating 0o to 70o centigrade Non Operating 50o to 125o centigrade Relative Humidity Operating 5 to 95 non condensing Altitude Operating 400 to 18 000 meters MSL 1 3 8 DIGITAL SYNCHRONIZATION SIGNALS Format DSS Signal RS 422 Communication 96...

Страница 13: ...CHAPTER ONE 1 6 bc620 627AT Time and Frequency Processor Symmetricom Inc This Page Intentionally Left Blank Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 14: ... 0 0 0 0 140H ON OFF ON OFF ON ON 0 0 0 0 150H ON OFF ON OFF ON OFF 0 0 0 0 160H ON OFF ON OFF OFF ON 0 0 0 0 170H ON OFF ON OFF OFF OFF 0 0 0 0 180H ON OFF OFF ON ON ON 0 0 0 0 190H ON OFF OFF ON ON OFF 0 0 0 0 1A0H ON OFF OFF ON OFF ON 0 0 0 0 1B0H ON OFF OFF ON OFF OFF 0 0 0 0 1C0H ON OFF OFF OFF ON ON 0 0 0 0 1D0H ON OFF OFF OFF ON OFF 0 0 0 0 1E0H ON OFF OFF OFF OFF ON 0 0 0 0 1F0H ON OFF OFF...

Страница 15: ...F OFF 0 0 0 0 240H OFF ON ON OFF ON ON 0 0 0 0 250H OFF ON ON OFF ON OFF 0 0 0 0 260H OFF ON ON OFF OFF ON 0 0 0 0 270H OFF ON ON OFF OFF OFF 0 0 0 0 280H OFF ON OFF ON ON ON 0 0 0 0 290H OFF ON OFF ON ON OFF 0 0 0 0 2A0H OFF ON OFF ON OFF ON 0 0 0 0 2B0H OFF ON OFF ON OFF OFF 0 0 0 0 2C0H OFF ON OFF OFF ON ON 0 0 0 0 2D0H OFF ON OFF OFF ON OFF 0 0 0 0 2E0H OFF ON OFF OFF OFF ON 0 0 0 0 2F0H OFF O...

Страница 16: ...assis cover Base Addr S1 A9 S2 A8 S3 S7 S4 A6 S5 A5 S6 A4 A3 A2 A1 A0 300H OFF OFF ON ON ON ON 0 0 0 0 310H OFF OFF ON ON ON OFF 0 0 0 0 320H OFF OFF ON ON OFF ON 0 0 0 0 330H OFF OFF ON ON OFF OFF 0 0 0 0 340H OFF OFF ON OFF ON ON 0 0 0 0 350H OFF OFF ON OFF ON OFF 0 0 0 0 360H OFF OFF ON OFF OFF ON 0 0 0 0 370H OFF OFF ON OFF OFF OFF 0 0 0 0 380H OFF OFF OFF ON ON ON 0 0 0 0 390H OFF OFF OFF ON ...

Страница 17: ...software 2 4 MSDOS DEVICE DRIVER bc620 627AT DOS Clock Device Driver v2 0 A device driver is supplied with the bc620 627AT This driver is intended to replace the PC real time clock in all aspects time and date stamping of files high level language calls time and date requests from the DOS prompt and any other applications which use the DOS clock INT21 funcs 2A 2B 2C or 2D The driver is installed b...

Страница 18: ...digits of offset in hours from GMT Allowed values Sign or hours 0 12 Default 0 Yxx Year One or two digits of year information Allowed values 91 10 Default 94 Note Year values less than ninety one will be assumed to mean twenty first century None of the switches are required and the switches may be added in any order The user is free to set only those switches which are necessary for the particular...

Страница 19: ...A240 Y01 05 Description A240 Sets the location where the driver will find the board to 240H Y01 Sets the driver initial year value to 2001 05 Sets the time returned by the driver to reflect 5 hrs ahead of GMT device bc620 sys A310 Y4 O 03 M2 Description A310 Sets the location where the driver will find the board to 310H Y4 Sets the driver initial year value to 2004 O 03 Sets the time returned by t...

Страница 20: ...CHAPTER TWO 2 8 bc620 627AT Time and Frequency Processor Symmetricom Inc This Page Intentionally Left Blank Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 21: ...maintain time or frequency or both after the input reference is removed or lost Periodic A programmable frequency which is obtained by dividing the TFP reference frequency Periodics are sometimes referred to as heartbeats Periodics may optionally be synchronous with the 1pps epoch if the period is expressible as a ratio of integers Major Time Units of time larger than or equal to seconds A day hr ...

Страница 22: ...ef description of the register s function 3 1 1 PAGE SELECT REGISTER PAGE 0 1 The page select register is used to activate one of two 16 byte banks of registers Bit 0 of PAGE selects PAGE 0 or PAGE 1 bits 1 7 are ignored during writes and undefined during reads PAGE is always accessible 3 1 2 TIMEREQ AND TIME0 TIME7 REGISTERS PAGE 0 Reading the TIMEREQ register causes the current time days microse...

Страница 23: ... 6 0 Frequency stability 5 parts in 10EX relative to time source 1 Frequency stability 5 parts in 10EX relative to time source X 7 for Mode 0 X 8 for all other Modes Bit 7 Currently unused A second independent one hundred nanosecond bus time request is supported with the UNLOCK and EVENT0 EVENT8 registers See sections 3 1 4 and 3 1 5 Note Register bits which are designated as unused are ignored du...

Страница 24: ...tatus DH 2 R 0 TIME 1 Time Byte 1 DT DU 3 R 0 TIME 2 Time Byte 2 HT HU 4 R 0 TIME 3 Time Byte 3 MT MU 5 R 0 TIME 4 Time Byte 4 ST SU 6 R 0 TIME 5 Time Byte 5 MSH MST 7 R 0 TIME 6 Time Byte 6 MSU USH 8 R 0 TIME 7 Time Byte 7 UST USU 9 Not Used A Not Used B Not Used C Not Used D Not Used E Not Used F R W 0 PAGE Page Select Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www...

Страница 25: ... Strobe Time 3 MT MU 5 5 R W 0 0 EVENT 4 STROBE 4 Event Time 4 ST SU Strobe Time 4 ST SU 6 6 R W 0 0 EVENT 5 STROBE 5 Event Time 5 MSH MST Strobe Time 5 MSH MST 7 7 R W 0 0 EVENT 6 STROBE 6 Event Time 6 MSU USH Strobe Time 6 MSU XX 8 R 0 EVENT 7 Event Time 7 UST USU 9 R 0 EVENT 8 Event Time 8 NSH XX A R W UNLOCK Lockout Release Capture Time B R W 0 ACK Data Acknowledge C R W 0 MASK Interrupt Mask ...

Страница 26: ...2 STROBE2 Hours Tens Hours Units TIME3 EVENT3 STROBE3 Minutes Tens Minutes Units TIME4 EVENT4 STROBE4 Seconds Tens Seconds Units TIME5 EVENT5 STROBE5 Milliseconds Hundreds Milliseconds Tens TIME6 EVENT6 STROBE6 Milliseconds Units Microseconds Hundreds not used for STROBE6 TIME7 EVENT7 Microseconds Tens Microseconds Units EVENT8 Nanoseconds Hundreds Undefined Artisan Technology Group Quality Instru...

Страница 27: ...equency Select 00 10 MHz 01 5 MHz 1X 1 MHz X don t care 7 FREQSEL1 3 1 3 CR0 CONTROL REGISTER 0 PAGE 1 CR0 controls various functions on the TFP event time capture periodic time capture time capture lockout event input sense strobe output strobe mode clock frequency output Table 3 4 summarizes the function of each bit in CR0 Each bit is described below LOCKEN Enables disables the time capture lock...

Страница 28: ...te from the TIME0 TIME7 registers on page 0 Time is captured to a resolution of 100 nanoseconds The time capture lockout feature prevents the EVENT0 EVENT8 registers from being overwritten with a new time before they can be read See Section 3 2 3 3 Table 3 3 shows the time data format for these registers 3 1 5 UNLOCK REGISTER PAGE 1 To release the time capture lockout mechanism the UNLOCK register...

Страница 29: ... cleared by writing a one to that bit location For example writing the value 0x01 to ACK will clear bit 0 and leave bit 1 unaltered Writing the value 0x03 to ACK will clear both bit 0 and bit 1 Table 3 5 ACK Acknowledge Register bit CONTROL FUNCTION SET 1 high voltage CLEAR 0 low voltage 0 TFP HOST SETS bit to acknowledge the receipt of a valid input packet from host CLEARS bit by writing to this ...

Страница 30: ...rrupt Interrupts will not occur unless the INTSTAT bit transitions from a 0 to a 1 while the respective MASK bit is set 3 1 8 INTSTAT INTERRUPT STATUS REGISTER PAGE 1 Each of the five interrupt sources will set the corresponding INTSTAT register bit to 1 when activated The INTSTAT bits will be set even if the corresponding MASK bit is cleared The INTSTAT register allows polling of the interrupt so...

Страница 31: ...pective PAGE registers will be active until the PAGE register is changed 3 2 2 READING TIME ON DEMAND A read of the TIMEREQ register will latch the current time days through microseconds and this time will remain in the TIME0 TIME7 registers until a subsequent read of TIMEREQ The TIME0 TIME7 registers can be read immediately after reading TIMEREQ A second bus time request is supported with the EVE...

Страница 32: ...xternal event or periodic to capture time once then subsequent capture signals will be blocked until the lockout is released The lockout is released by reading the UNLOCK register The time capture lockout feature is enabled with LOCKEN CR0 bit 0 A write instruction to the UNLOCK register will latch time in the EVENT0 EVENT8 registers 3 2 4 TIME COINCIDENCE STROBE OUTPUT The TFP provides a time coi...

Страница 33: ...I ETB See Chapter Four for a description of the available FIFO data packets and programming protocol 3 3 PC AT INTERRUPTS The TFP supports the five interrupt sources listed in Table 3 6 Interrupts are maskable with the MASK register When multiple interrupt sources are enabled in the MASK register the interrupt service routine can read the INTSTAT register to determine which interrupt source s caus...

Страница 34: ...CHAPTER THREE 3 14 bc620 627AT Time and Frequency Processor Symmetricom Inc This Page Intentionally Left Blank Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 35: ...t is generated to the TFP CPU the TFP service routine performs minimalist packet integrity checking The TFP checks that the first packet byte is 0x01 ASCII SOH If the SOH is found the TFP loads FIFO data into an input buffer until a byte value of 0x17 ASCII ETB is found The packet is then processed in accordance with the idbyte value When processing is complete the TFP sets bit 1 of the ACK regist...

Страница 36: ...1pps input the TFP runs at the last known oscillator frequency Major time can be set with the B packet The TFP time base can be adjusted with packet D MODE 2 EXTERNAL 1PPS MODE The TFP synchronizes to the external 1pps input signal Major time can be loaded with the B packet The acquisition range is the same as described in mode 0 MODE 2 is used when a primary time standard such as a GPS receiver i...

Страница 37: ...cond epoch was perfect then the number of counts in the one second epoch would be exactly two million There would be thirty periods plus a remainder of 33920 counts For now it is important to know that the bc620 627AT increments and then transfers major time from a software buffer to a set of hardware latches on the 29th period of the internal counter The time loaded into the latches will be the m...

Страница 38: ... current TFP time Commands three and four are provided for advanced users who may need to exercise control over the normal flow of the bc620 firmware Issuing a jam sync can be useful when using an external fixed oscillator that can not be disciplined Command four has no known useful purpose It was initially implemented during the TFP checkout phase and has not been removed The bc620 c file has an ...

Страница 39: ...abled using the path packet P to prevent the bc620 from overwriting the data input with this packet D The bc620 c file has an example function preset_DA which presets the D A as described above 4 1 5 PACKET F HEARTBEAT PERIODICS CONTROL The programmable frequency output is a very powerful bc620 627AT feature Feedback from the users of other board level products motivated the inclusion of a very co...

Страница 40: ...chronous Mode 2 to 65535 Synchronous Mode 3 to 65535 WARNING Periodic heartbeat pulse interrupt generation can not be guaranteed in synchronous mode when counter divide values of two are used The two modes of operation are accessed using standard INTEL mode identifiers For synchronous operation the mode byte must be an ASCII 5 For asynchronous operation the mode byte must be an ASCII 2 The packet ...

Страница 41: ... byte 9 0 byte 10 6 byte 11 3 n2 99 0x63 byte 12 ETB The bc620 c file has an example function load_82C54 illustrating the use of this packet 4 1 6 PACKET G PROPAGATION DELAY OFFSET CONTROL It is frequently desirable to be able to program an offset into the basic timekeeping functions relative to the reference input For example if the reference input is IRIG B test range time there may be a signifi...

Страница 42: ...the reference time and the TFP time is detected to be greater than 1 millisecond the TFP time base is jammed to the reference time so that a lengthy steering process is avoided 4 1 7 PACKET H SET TIME CODE FORMAT FOR MODE 0 Packet H allows the host to select the format and modulation type The packet format is as follows The time code format and modulation values are maintained in battery backed RA...

Страница 43: ... 1 SOH byte 2 I byte 3 E or I External or Internal byte 4 ETB On power on the TFP always defaults to the internal oscillator selection 4 1 9 PACKET J SEND DATA TO THE GPS RECEIVER bc627AT only The format and content variations are discussed in a separate User s Guide 4 1 10 PACKET K SELECT GENERATOR CODE The time code generated by the TFP is selected by packet K Only two options are available as d...

Страница 44: ...ata is in the ASCII format The TFP need not be in Mode 3 when packet L is downloaded 4 1 12 PACKET M LOCAL TIME OFFSET SELECT bc627AT GPS Mode 4 Only This packet allows time to be maintained with an hour offset This situation usually arises when the source of time is in a UTC Universal Time Coordinated format and the local time is required from the TFP The offset only applies to the hours digits T...

Страница 45: ...his bit by writing to the ACK register with bit2 set Note The user is advised against repetitively issuing Packet O to the TFP Processing overhead is introduced to the TFP on board CPU which could momentarily disrupt time keeping The packet format follows REQUEST FORMAT byte 1 SOH byte 2 O Upper case letter byte 3 0 or 1 or 2 byte 4 ETB RESPONSE FORMAT 0 REQUEST RTC TIME see Packet L byte 1 SOH by...

Страница 46: ...er byte 3 1 byte 4 0 F bits 12 15 byte 5 0 F bits 08 11 byte 6 0 F bits 04 07 byte 7 0 F bits 00 03 byte 8 ETB RESPONSE FORMAT 2 REQUEST LEAP SECONDS currently GPS specific byte 1 SOH byte 2 o Lower case letter byte 3 2 byte 4 Leap Second Tens byte 5 Leap Second Units byte 6 ETB Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 47: ...ay Offset Millisecond Hundreds byte 15 Propagation Delay Offset Millisecond Tens byte 16 Propagation Delay Offset Millisecond Units byte 17 Propagation Delay Offset Microsecond Hundreds byte 18 Propagation Delay Offset Microsecond Tens byte 19 Propagation Delay Offset Microsecond Units byte 20 Propagation Delay Offset Nanosecond Hundreds byte 21 Heartbeat Mode See Packet F byte 22 Heartbeat Cnt1 B...

Страница 48: ...Model 7 T byte 11 Model 8 byte 12 Version 1 9 byte 13 Version 2 5 byte 14 Version 3 0 byte 15 Version 4 0 to 9 byte 16 Version 5 0 to 9 byte 17 Version 6 0 to 9 byte 18 Version 7 0 to 9 byte 19 ETB RESPONSE FORMAT 5 REQUEST YEAR currently bc627AT GPS specific byte 1 SOH byte 2 o lower case letter byte 3 5 byte 4 Year Thousands byte 5 Year Hundreds byte 6 Year Tens byte 7 Year Units byte 8 ETB Arti...

Страница 49: ... Code to Static 1 Dynamics Code to Non static 2 Bit 3 0 Packed BCD Time Format 1 long second format 3 1 UTC time GPS time GPS leap seconds GPS time does not use GPS leap seconds 2 Auto set of GPS dynamics code to Static by bc627AT after initialization to GPS Allows accurate time keeping without a full position fix for stationary users 3 Major time over PCbus is binary seconds since Jan 6 1980 Mino...

Страница 50: ...0 F least significant nibble byte 4 0 F most significant nibble byte 5 sense 1 positive default 0 negative byte 6 ETB 4 1 16 PACKET R GENERATOR TIME OFFSET SELECT This packet allows the time code generator output to be offset from the TFP time This is useful for example when UTC time is maintained in the TFP but local time must be generated to other devices such as time displays The offset only ap...

Страница 51: ...efine FIFO BASE 0x0E define PAGE BASE 0x0F define TIME0 BASE 0x01 The following global variables are also declared and used throughout this chapter char i dummy time 9 5 1 READING TIME ON DEMAND The following example reads the time from the TFP registers TIME0 thru TIME7 and loads this data into the array time Note that the time is latched by reading the TIMEREQ register and that the register is a...

Страница 52: ... PERIODIC FREQUENCY OF 1000 Hz This example uses a generalized send_packet function to program a 1000 Hz output periodic synchronized to the TFP 1pps epoch void send_packet char charptr outportb FIFO SOH while charptr outportb FIFO charptr load body of packet outportb FIFO ETB outportb ACK 0x81 command TFP clear ACK while inportb ACK 0x01 wait for TFP acknowledge Code Fragment which sets Periodic ...

Страница 53: ...P packet is used to disable jamsynchs since the required offset is larger than 990 microseconds See the G packet description for additional details on the jamsynch function send_packet A0 select mode 0 send_packet HB select IRIG B time code send_packet G 0025000 advance 2 5 milliseconds send_packet P04 disable jamsynchs Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www ...

Страница 54: ...CHAPTER FIVE 5 4 bc620 627AT Time and Frequency Processor Symmetricom Inc This Page Intentionally Left Blank Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 55: ...he bc627AT Table 6 1 J1 Pinouts Signals On J1 15 Pin DS Signals On J2 15 Pin DP Pin Signal Pin Signal 1 External 10 MHz input 1 RS 422 Rx 2 Ground 2 RS 422 Rx 3 Strobe Output 3 RS 422 Tx 4 1 PPS Output 4 RS 422 Tx 5 Time Code Output AM 5 Ground 6 External Event Input 6 Not Used 7 Time Code Input AM 7 GPS 1 PPS 8 Ground Recommended Time Code Return 8 GPS 1 PPS RS 422 Rx 9 Oscillator Control Output ...

Страница 56: ...to 2 IRQ15 3 to 4 IRQ14 5 to 6 IRQ12 7 to 8 IRQ11 9 to 10 IRQ10 11 to 12 IRQ9 13 to 14 IRQ7 15 to 16 IRQ6 17 to 18 IRQ5 19 to 20 IRQ4 21 to 22 IRQ3 22 to 23 No IRQ Table 6 3 JP2 Jumper Positions for RS 422 RX 100 OHM Termination JP2 Position RS 422 Rx 100 Ω Termination 1 to 2 Terminated 3 to 4 No Termination Indicates factory default position Artisan Technology Group Quality Instrumentation Guaran...

Страница 57: ... trace oscilloscope and a time code input Set the bc620 627AT to Mode 0 Packet A and select the appropriate time code format and modulation type Packet H Connect channel 1 of the oscilloscope to pin 16 of U19 XR2212 Connect channel 2 of the oscilloscope to the modulated input time code Trigger the oscilloscope on the channel 1 input Adjust RV2 so that the positive transition of the TTL signal inpu...

Страница 58: ...e amplitude of the modulated IRIG B output time code A value of one volt RMS is common as is three volts peak to peak on the high cycles Adjust this value to suit the equipment being driven The range is zero to twenty four volts peak to peak Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 59: ... intercept test data on magnetic tape recorders for post processing and time correlation Hundreds of time code formats were developed one for each agency involved During the early 1960 s the InterRange Instrumentation Group IRIG promoted a series of standard time code formats now loosely referred to as IRIG Time Codes The bc620 627AT decodes the most widely used format IRIG B as well as IRIG A Fig...

Страница 60: ...APPENDIX A A 2 bc620 627AT Time and Frequency Processor Symmetricom Inc Figure A 1 IRIG Time Code Frame Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 61: ...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 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 62: ...l service in house repair center WE BUY USED EQUIPMENT Sell your excess underutilized and idle used equipment We also offer credit for buy backs and trade ins www artisantg com WeBuyEquipment REMOTE INSPECTION Remotely inspect equipment before purchasing with our interactive website at www instraview com LOOKING FOR MORE INFORMATION Visit us on the web at www artisantg com for more information on ...

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