Vremya-ch VCH-315M User manual


V R E M Y A –C H
Joint Stock Company
MULTICHANNEL FREQUENCY COMPARATOR
VCH-315M
Operation Manual
411146.039OM
Osharskaya str., 67, Nizhny Novgorod, 603105, Russia
tel./ fax [phone], http://www.vremya-ch.com
Инв. № подл.
Подп. и дата
Взам. инв.№
Инв. № дубл.
Подп. и дата

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Table of contents
1List of abbreviations........................................................................................ 3
2Safety precaution............................................................................................. 4
3Device description........................................................................................... 5
3.1 Description and operation...................................................................... 5
3.2 Key applications..................................................................................... 5
3.3 Product composition ..............................................................................7
3.4 Product specifications ............................................................................8
3.5 Basic configuration and operation .......................................................11
4Operating 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
5Troubleshooting ............................................................................................ 34

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1List of abbreviations
ADEV –Allan deviation
PC –personal computer
RS232 –serial port
Multichannel frequency Comparator VCH-315M –device

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2Safety precaution
2.1 Carefully read the operating manual before working with the device and note the
safety information.
2.2 Accessible conductive parts of the device are protected by basic insulation and
electrically connected to the protective grounding.
2.3 The device is grounded via protective conductor in the power cable and
protective earth terminal marked on the rear panel.
2.4 The device is connected to the AC via 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 must be carried out by qualified
personnel authorized for work on high voltage (up to 1000V).
2.9 RS-232 interface cable should be connected only when the the device is turned
off. Failure to do so may result in damage to the interface.

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3Device description
3.1 Description and operation
Multichannel frequency comparator VCH-315M is intended for simultaneous
frequency instability measurements of a group of sinusoidal signals 5, 10, 100 MHz.
Device can be managed and measurement results can be displayed and stored
using a PC and special software. Monitored parameters 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. Built-in RS-232,
USB and LAN interfaces provide remote measurement of the monitored
signals frequency instability characteristics.

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Figure 1 –External view of the device

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3.3 Product composition
The device composition is given in Table 1.
Table 1 –Device composition
№
Model and designation
Quantity
1.
Multichannel frequency comparator VCH-315M
1
2.
Fuse 3,15 A
6
3.
Power 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

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3.4 Product specifications
3.4.1 The device is managed and measurement results are displayed and stored using a
PC. Monitored parameters and control commands are transferred via RS-232
interface, USB or LAN. The PC must meet the following minimum
requirements:
−Processor: Intel Pentium-IV 2 GHz 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.
3.4.6 Warm-up time:
−2 h, for averaging time range not more 100 s;
−6 h, for averaging time range >100 s.

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3.4.7 Frequency instability introduced by device –Allan deviation (at zero frequency
difference between input signals and temperature deviation not more than
±1,0 °С per hour within the operating temperature range), is displayed in the
Table 2.
Table 2 –Frequency instability, introduced by device
Averaging
time, 
Frequency instability introduced
by Multichannel frequency comparator VCH-315M
“One-channel” mode,
ADEV
“Two-channels” 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) V, (50±1) Hz;
−DC power supply: (22 –30) V.
3.4.10 In the absence of AC voltage the device automatically switches to backup
power from an external DC source. The device will retain its specifications
during the AC/DC change-over.

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3.4.11 Power consumption:
−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.