Vremya-ch VCH-315M Operation Manual Download Page 21

 

 

21 

4.4

 

Operating procedure 

4.4.1

 

Measurement process 

Connect  the  measured  signals  according  to  the  selected  operating  mode  (see 

section 4.5 of this Operating manual).  

Connection is carried out by coaxial cables with wave resistance of 50 Ohm and 

SMA  type  connectors.  The  tightening  torque  of  SMA  connectors  should  be  between 

0.8 and 1.1 N·m. 

The device will be ready for use with the guaranteed frequency instability given 

in Table 2 after a warm-up period. 

Start  the  measurements  in  the  Multichannel  frequency  comparator  program 

following  the  instructions  in  the  "Multichannel  frequency  comparator  VCH-315M 

User guide". 

You  can  view  the  instability  characteristics  of  the  frequency  of  measured 

sinusoidal  signals  during  or  after  the  end  of  the  measurements  following  the 

instructions  in  the  "Multichannel  frequency  comparator  VCH-315M  User  guide"  and 

"Program  for  processing  measurement  data  of  frequency  comparators/counters" 

Analyzer "User guide". 

Summary of Contents for VCH-315M

Page 1: ...k Company MULTICHANNEL FREQUENCY COMPARATOR VCH 315M Operation Manual 411146 039OM Osharskaya str 67 Nizhny Novgorod 603105 Russia tel fax 7 831 421 02 94 http www vremya ch com Инв подл Подп и дата Взам инв Инв дубл Подп и дата ...

Page 2: ...2 Key applications 5 3 3 Product composition 7 3 4 Product specifications 8 3 5 Basic configuration and operation 11 4 Operating procedure 15 4 1 Safety requirements 15 4 2 Location of control and connection systems 15 4 3 Preparing the device for use 17 4 4 Operating procedure 21 4 5 Measurement modes 22 5 Troubleshooting 34 ...

Page 3: ...3 1 List of abbreviations ADEV Allan deviation PC personal computer RS232 serial port Multichannel frequency Comparator VCH 315M device ...

Page 4: ... three wire power cable two poles and ground included in the device kit 2 5 To avoid the influence of static electricity all further connections must be made only with the grounded device 2 6 You must avoid contact with current carrying parts during repair as it may result in shock 2 7 Before touching any components or wiring always unplug the device 2 8 All repair and maintenance of the device mu...

Page 5: ...rameters and control commands are transferred via RS 232 interface USB or local area network LAN The external view of the device is given in Fig 1 3 2 Key applications The main applications of the device crystal and quantum frequency standards production and checking scientific research in metrology as an integral part of the storage systems as an integral part of automated measurement systems Bui...

Page 6: ...6 Figure 1 External view of the device ...

Page 7: ...er connecting cord 1 4 Interface RS 232 cable 685622 003 1 5 Interface cable USB 2 0 AM BM 1 8M 1 6 Power splitter ZFSC 2 1W S 2 7 RF interconnecting cable 685670 372 4 8 RF interconnecting cable 685670 376 2 9 Multichannel frequency comparator VCH 315M Installation disc 1 10 Multichannel frequency comparator VCH 315M Operating Manual 1 11 Multichannel frequency comparator VCH 315M User guide 1 ...

Page 8: ... or similar Operating system Microsoft WindowsTM XP Vista 7 8 10 RAM 512 MB 3 4 2 Input signal parameters nominal frequencies 5 10 100 MHz RMS voltage 1 0 0 2 V at 50 1 Ohm relative frequency difference 5 0 10 9 to 5 0 10 9 3 4 3 Number of measuring channels 8 eight modules with two inputs for the measured signals fх fy 3 4 4 Averaging time range from 1 s up to 1 day 3 4 5 Noise passband 3 Hz 3 4 ...

Page 9: ...els mode cross ADEV 1 s 6 0 10 14 2 0 10 14 10 s 2 0 10 14 3 0 10 15 100 s 3 0 10 15 1 0 10 15 1 h and more 3 0 10 16 2 0 10 16 Note frequency instability introduced by the comparator is guaranteed after warm up time according to s 3 4 6 3 4 8 The device provides continuous non stop operation in working conditions with all specifications preserved 3 4 9 Power supply voltage AC power supply 220 22 ...

Page 10: ... AC power supply not more 40 VA DC power supply not more 35 W 3 4 12 Ambient temperature operating 5 to 40 С non operating 50 to 50 С 3 4 13 Weight no more than 12 kg net 16 kg in factory package 3 4 14 Dimensions 133 483 325 mm ...

Page 11: ...e measurements to the computer where all the data is processed by a special program that gives the characteristics of the input signals instability in digital and graphical forms 3 5 2 Description of the circuit diagram Circuit diagram illustrating the operating principle of the device is shown in Figure 2 The device consists of these main parts eight identical frequency comparators channels proce...

Page 12: ...on of the frequency comparators by commands from the special program and also controls the indicators Transmission of measurement data to the computer and reception of control commands is carried out by the processor via RS 232 USB or LAN interfaces Tested signals 5 10 100 MHz SIGNALS AND POWER BUS INDICATION SIGNAL DRIVER fy fx FREQUENCY COMPARATOR 1 CHANNEL 1 tyx fy fx FREQUENCY COMPARATOR 8 CHA...

Page 13: ...Ds turning on and off at a frequency of about 1 Hz The front panel also contains the AC 220 V power indicator and the external DC source indicator Indication signal driver generates indication signals and sends them to the front panel indicators by the processor command Power supply and internal information exchange between the device units are carried out via the signals and power bus The device ...

Page 14: ... automatic update of charts and statistical characteristics a wide range of computed parameters mean relative frequency difference and frequency drift by least squares method standard deviation Allan deviation Hadamard deviation maximum time interval error time interval deviation power spectral density of phase and frequency noise calculation of the statistical characteristics with overlap method ...

Page 15: ...is prohibited The device is connected to the AC via three wire power cable two poles and ground included in the device composition ATTENTION Usage of any other power plugs is STRICTLY PROHIBITED Operation of the device must comply with the electrical safety regulations in force at the operating facility 4 2 Location of control and connection systems Connectors indicators and control elements on th...

Page 16: ...16 Figure 3 Connectors indicators and control elements on the front and rear panels ...

Page 17: ... Normal operation indicator of the power supply unit 13 Ground terminal 4 3 Preparing the device for use 4 3 1 Operational limitations It is recommended to place the device in a thermostabilized room with limited access to personnel The place for the device should be chosen taking into account the dimensions of the device 133 483 325 mm and the need for free convection of air through the ventilati...

Page 18: ... before starting Note the location of the controls and connections Figure 3 for their purpose Table 3 Ensure reliable grounding of the device The protective grounding terminal should be connected to the grounding conductor before other connections The fasteners of the ground terminal and the conductors must be securely fixed While the power is off connect the device to the computer in one of the f...

Page 19: ...urce Make sure that the POWER NORM and 22 30 V 35 W indicators on the power module panel are lit The 22 30 V indicator on the power unit panel lights up only if there is a DC voltage on the 22 30 V 35 W connector To connect an external power source use a power cable with a 2PMT14КПН4Г1В1 2PM14 4TKQB2 type connector Pin 1 of the connector must be connected to the positive pole of the DC power suppl...

Page 20: ...nt data of frequency comparators counters Analyser User Guide Before using the USB interface of the device install a PC driver that creates a virtual serial port when connecting the comparator via the USB interface following the instructions in the Multichannel frequency comparator VCH 315M User guide To control the device via the Ethernet install the special software following the instructions in...

Page 21: ...use with the guaranteed frequency instability given in Table 2 after a warm up period Start the measurements in the Multichannel frequency comparator program following the instructions in the Multichannel frequency comparator VCH 315M User guide You can view the instability characteristics of the frequency of measured sinusoidal signals during or after the end of the measurements following the ins...

Page 22: ...umption that frequency fluctuations of all signals and measuring channel are independent Table 3 Available functions for two oscillators one channel mode Number Calculated function Mathematical expectation 1 Relative frequency difference measured for CHANNEL 1 N c N x N y y y y 1 1 1 2 Standard deviation measured for CHANNEL 1 2 1 2 1 2 1 c x y 3 Allan deviation measured for CHANNEL 1 2 1 2 1 2 1 ...

Page 23: ... signal and measurement channel is much less than that of measured signal Signal Source Y1 RS 232 interface cable included with the instrument set composition UTP cable 8P8C plug Personal Computer Multichannel frequency comparator VCH 315M fy fx CHANNEL 1 RS 232 LAN 220 V 50 Hz 40 V A 22 30 V 35 W POWER SUPPLY PROCESSOR USB Power connecting cord AC power connecting cord connector 2PMT14КПН4Г1В1 US...

Page 24: ... the measurement results And the measurement error introduced by the channel can be reduced using cross correlation processing The channels noise can be estimated along with the measured signals instability Accuracy of estimations depends on the measurement time interval Table 4 shows mathematical expectation of calculated functions for the measuring channels pair CHANNEL 1 and CHANNEL 2 These fun...

Page 25: ... 1 2 1 2 1 c x y 5 Standard deviation measured in CHANNEL 2 2 2 2 1 2 1 c x у 6 Sum standard deviation CHANNEL 1 and CHANNEL 2 2 2 2 1 c c 7 Standard cross deviation CHANNEL 1 and CHANNEL 2 2 1 2 1 x y 8 Allan deviation measured in CHANNEL 1 2 1 2 1 2 1 c x y 9 Allan deviation measured in CHANNEL 2 2 2 2 1 2 1 c x y 10 Sum Allan deviation CHANNEL 1 and CHANNEL 2 2 2 2 1 c c 11 Allan cross deviatio...

Page 26: ...t composition UTP cable 8P8C plug Personal Computer Multichannel frequency comparator VCH 315M fy fx CHANNEL 1 RS 232 LAN 220 V 50 Hz 40 V A 22 30 V 35 W POWER SUPPLY PROCESSOR USB Power connecting cord AC power connecting cord connector 2PMT14КПН4 USB interface cable fy fx CHANNEL 2 CHANNEL 3 CHANNEL 4 CHANNEL 8 fy fx fy fx fy fx Signal source Y1 Signal source X1 Connecting cables 50 Ohm Connecti...

Page 27: ... of the instability of each individual oscillator reduced systematic error caused by instability of reference signal and measuring channel RS 232 interface cable included with the instrument set composition UTP cable 8P8C plug Personal Computer Multichannel frequency comparator VCH 315M fy fx CHANNEL 1 RS 232 LAN 220 V 50 Hz 40 V A 22 30 V 35 W POWER SUPPLY PROCESSOR USB Power connecting cord AC p...

Page 28: ...CHANNEL 2 N c N c N y N y y y y y 3 1 3 1 5 Sum relative frequency difference CHANNEL 2 and CHANNEL 3 N c N c N y N y y y y y 1 2 1 2 6 Sum relative frequency difference CHANNEL 3 and CHANNEL 1 N c N c N y N y y y y y 2 3 2 3 7 Standard deviation measured in CHANNEL 1 2 1 2 3 2 1 c y y 8 Standard deviation measured in CHANNEL 2 2 2 2 1 2 2 c y y 9 Standard deviation measured in CHANNEL 3 2 2 2 2 2...

Page 29: ...rd cross deviation CHANNEL 3 2 3 2 2 c y 21 Standard cross deviation CHANNEL 1 2 1 2 3 c y 22 Allan deviation measured in CHANNEL 1 2 1 2 3 2 1 c y y 23 Allan deviation measured in CHANNEL 2 2 1 2 1 2 2 c y y 24 Allan deviation measured in CHANNEL 3 2 1 2 2 2 3 c y y 25 Sum Allan deviation CHANNEL 1 and CHANNEL 2 2 2 2 1 2 2 2 3 c c y y 26 Sum Allan deviation CHANNEL 2 and CHANNEL 3 2 3 2 2 2 3 2 ...

Page 30: ...7 give systematic error caused by instability of reference signal in both channels and instability of measuring channels Formulas 14 15 17 18 20 21 29 30 32 33 35 36 give systematic error caused by instability of measuring channels Formulas 13 16 19 28 31 34 give non biased estimations We can measure without systematic error only Y1 signal in measuring channels CHANNEL 1 CHANNEL 2 only Y2 signal i...

Page 31: ...connect the device and sine signal source with frequency distribution amplifier in the example for CHANNEL 1 2 or with power splitters in the example for CHANNEL 4 8 as shown in Figure 8 After 6 hour warm up time start measuring frequency instability Allan deviation introduced by measuring channels for averaging times 1 s 10 s 100 s 1000 s 1 h for 16 18 hours Note Use RF interconnecting SMA BNC ca...

Page 32: ...ed in CHANNEL 2 2 2 c 6 Sum standard deviation CHANNEL 1 and CHANNEL 2 2 2 2 1 c c 7 Standard cross deviation CHANNEL 1 and CHANNEL 2 0 8 Allan deviation measured in CHANNEL 1 2 1 c 9 Allan deviation measured in CHANNEL 2 2 2 c 10 Sum Allan deviation CHANNEL 1 and CHANNEL 2 2 2 2 1 c c 11 Allan cross deviation CHANNEL 1 and CHANNEL 2 0 Notes Formulas 4 5 6 8 9 10 give systematic error caused by ch...

Page 33: ...32 LAN 220 V 50 Hz 40 V A 22 30 V 35 W POWER SUPPLY PROCESSOR USB Power cord AC power cord connector 2PMT14КПН4 USB interface cable fy fx CHANNEL 2 CHANNEL 3 CHANNEL 4 CHANNEL 8 fy fx fy fx fy fx OUT A1 OUT A2 OUT A3 OUT A4 Frequency Distribution Amplifier IN A Signal Source X2 1 2 Power splitter ZFSC 2 1W s Signal Source X1 1 2 Power splitter ZFSC 2 1W s Connecting cables 50 Ohm ...

Page 34: ...er cord fault Repair or replace the cable Device malfunction Factory repair Front panel CHANNELS 1 2 3 4 5 6 7 8 indicators not flashing at 1 Hz when input signals are present No input signal Connect input signal Connecting cable fault Repair or replace the interconnecting cable Device malfunction Factory repair RS 232 communication failure RS 232 interface cable fault Repair or replace the RS 232...

Page 35: ...35 Problem Probable cause Solution Notes LAN communication failure Ethernet error Repair or replace the Ethernet cables Test the PC Ethernet interface Device malfunction Factory repair ...

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