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Frequency comparator VCH-308A

Frequency comparator VCH-308A is intended for precise measuring of frequency and time standards signal instability. The comparator contains built in time interval counter and an interface RS-232C.

Input signals: 1 Hz, 5 MHz, 10 MHz, 100 MHz (0,6 1,2V rms).

Maximal input relative frequency difference: (df/f) = 1x106.

Measuring time: t = 1 ms - 105 s.

Passband: 10000Hz, 1000Hz, 10Hz, 3Hz.

Measuring time tMain error (RMS @ df/f=0) not more
1-100 ms<3x1013/t (P = 1000 Hz)
1 s<7x1014 (P = 3 Hz)
10 s<1x1014 (P = 3 Hz)
100 s<2x1015 (P = 3 Hz)
>1000 s<5x1016 (P = 3 Hz)

Additional error at df/f: < 2x10-3 df/f.

1 PPS output to the external time interval counter (TTL levels on 50-Ohm load).

Application software (Microsoft Windows 9x,2000,XP):

- Calculates phase and frequency difference of input signals, 2-samples Allan variance, N-samples Allan variance, frequency fluctuations spectra.

- Represents results as tables and plots, stores information in files.

Power: 220 V; 50 - 60 Hz; < 40 VA.

Dimensions: 254x133x311 mm.

Weight: not more 6 kg.

GPS/GLONASS Disciplined Rb Oscillator VCH-311

GPS/GLONASS disciplined rubidium frequency standard model VCH-311 is a high stable frequency signal source (STANDARD mode), or precision frequency calibrator for any external standard signals (CALIBRATOR mode).

The instrument contains multi-channel GPS/GLONASS receiver, time scale comparison unit and automatically adjustable Rubidium reference oscillator.

Frequency error (STANDARD mode) is less than 3x10-12 in 24 hours of continuous work. Periodicity of correction of the built-in rubidium reference generator is 3 hours.

Output signals:

- 10MHz, 5 MHz sine, 1V rms on 50 Ohm load;

- 2.048 MHz, pulse, (ITU-T G.703 / 10);

- 1 PPS (TTL) - satellite time scale.

Frequency instability of output signals 10 and 5 MHz (STANDARD mode) is less than 7x10-12 in 10 seconds and 2x10-12 in 24 hours.

Output signals frequency accuracy depending on time expired from start up in STANDARD mode:

- 2x10-11 after 3 hours;

- 7x10-12 after 9 hours;

- 3x10-12 after 24 hours and longer.

Input signals from external frequency standard in CALIBRATOR mode: 10, 5 or 2.048 MHz with the amplitude 0,7 3,5 V on 75 Ohm load.

Frequency calibration accuracy (RMS value) is less than 1x10-12 in 24 hours and 1x10-13 in 10 days. The results of the measurement in relative units are represented on the indicator panel of the equipment.

Power: AC 220 V; 50 60 Hz, or DC 4810 V (have to be determined in purchase order).

Power consumption: 25W in normal conditions (warm up time 85W, 1 hour).

Dimensions: 483x140x330 mm.

Weight: less than 10 kg.

Antenna dimensions not more 185xø181 mm.

Antenna weight: 0,5 kg. The lead-in cable's length is 60 m.

Frequency Calibrator VCH-313

Frequency calibrator VCH-313 is intended for calibration and verification of different types of frequency standards, using precision signal, transmitted by satellite navigation systems GPS/GLONASS. The device can also perform periodical frequency correction of a calibrated frequency standard in special automatic mode.

Input signals from the external frequency standard: 1 MHz 20 MHz with the amplitude 0,7 3,5 V on 75 Ohms load. Input signal frequency is to be set by the user manually with the step 0,001 MHz.

Frequency calibration error of an input signal (frequency calibrator mode) depends on measurement time.

Minimal frequency calibration error for measurement time more than 10 days, is 1x10-13.

Calibrator forms the signal for an external standard frequency correction in digital or analog form. Adjustment slope is to be determined by user.

Power: AC 220V; 50 60 Hz, or DC 48 10V (depends on order).

Power consumption <15W.

Start up time <15 min.

Dimensions (without antenna and a cable): 340x235x140mm.

Weight: <3,5 kg.

Precision Frequency Comparator VCH-314

Frequency comparator VCH-314 is intended for precise phase and frequency instability measuring. It contains two identical measuring channels (three input signals). Using cross-correlation technique allows to obtain super-low measurement error and to calculate frequency instability of each single signal separately.

Input signals: 5 MHz; 10 MHz; 100 MHz (0,8 1,2V rms on 50 Ohm load).

Maximal frequency difference: (df/f) = 1x106.

Measuring time: 1 - 105 s.

Measurement error (inserted frequency instability):
Measuring TimeMain error (df/f=0, passband 3 Hz) not more than
-One channel modeTwo channels mode
1 s<8x1014<2x1014
10 s<2x1014<5x1015
100 s<3x1015<1.5x1015
>1000 s<5x1016<5x1016

Additional error at df/f: <2x103 (df/f).

Application software (Microsoft Windows 9x,2000,XP):

- calculates phase changing and frequency difference for each signals pair, 2-samples Allan variance, N-samples Allan variance for each signals pair and for each signal separately;

- represents results as tables and plots, stores information in files.

Interface: RS-232C.

Power: 220 V; 50-60 Hz; < 30 VA.

Dimensions: 254x133x311 mm.

Weight: < 8 kg.

Multichannel frequency Comparator VCH-315

The frequency comparator VCH-315 is a multichannel system for precise signals instability measuring.

The device is controlled by PC through RS-232C or LAN interface.

Input signals: sinusoidal 5 MHz, 10 MHz, 100 MHz; 0,8 1,2 V rms; pulse 1 Hz (as option).

Number of channels: 8.

Input impedance: 50 Ohm.

Maximal input relative frequency difference: df/f = 0,5x10-9.

Passband: (10 3) Hz.

Measuring time: t = 1 - 106 s.

Frequency difference measurement resolution: 1014/t.

Measurement error (frequency instability introduced by the device):
Measuring time tMain error (RMS @ df/f=0) not more
1 s1,5x1013
10 s2,0x1014
100 s3,0x1015
>1000 s5,0x1016

Additional error at df/f: <0.002df/f.

Application software:

  • runs under Microsoft Windows 9x,2000,XP;
  • calculates phase and frequency differences, Allan variance, frequency fluctuations spectra for each channel.
  • represents results as tables and plots, stores information in files.

Power: 220 V, 50 - 60 Hz.

Power consumption: < 40 BA.

Dimensions: 145x450x315 mm.

Weight: 7 kg.

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