SU1259498A2 - Device for automatic measuring of frequency responses of communication channels - Google Patents

Abstract

FIELD: radio engineering. In relation to a. with. P 924876 improves measurement accuracy by eliminating communication channels. The device contains program block 1, two oscillators 2, 3, channel switch (k) 4, K 5, reversing register 6, display block 7, control unit 8, mixer 9, / selective amplifier 10, analog-code converter 11. Newly introduced bandpass filter 12, quadratic detector 13, integrator 14, threshold. block (PB) 15, relay 16 with a normally closed contact (NLC) 17. The definition of channel occupancy is made by analyzing the level of the signal coming in through K 4 to filter 12, limiting the level of spurious interference. The signal is then rectified by the detector 13 and, via the integrator 14, arrives at PB 15. The threshold for triggering PB 15 is set above the noise level and below the signal level. The output signal of PB 15 triggers the operation of the relay, while opening the NZK 17, delaying the issuance of the command for K 4 and the production of measurements. When the channel is empty, relay 16 does not operate and a measurement is taken. Unit 1 issues a command to K 4 to connect the output of generator 2 to the input of the measured channel, and its output to mixer 9, to K 5 issues a command to connect converter 11 to register 6 and to the device for similar switches: . 1 nl after that

Description

The invention relates to radio engineering, can be used in complexes of automated quality control of communication channels and. is an improvement of the invention on author. St. No. 924876.

The purpose of the invention is to increase the reliability of measurement by eliminating busy communication channels.

The drawing shows a structural electrical circuit of the proposed device.

The device for automatic measurement of frequency characteristics of communication channels contains program block 1, two oscillators 2 and 3, channel switch 4j switch 5, reversing register 6, display unit 7, control unit 8, mixer 9, selective amplifier 10, analog-code converter 11, bandpass filter 12, quadratic detector 13, integrator 14, threshold unit 15, relay 16 with normally closed contact 17.

The device works in the following way.

By the command Start measurement, information about the required frequency of both oscillators 2 and 3 is read from block 7 and through program block 1 arrives at generators 2 and 3. At the same time, this command is sent to a similar device in executive mode at the other end of the communication channel. The software unit 1 issues commands to the channel switch 4 to connect the generator 2 to the input of the mixer 9 and connect in parallel to the input of the measured channel the high-resistance input of the band-pass filter 12, and switch 5 to connect the analog-code 11 output of the converter to the addition or subtraction of the reverse register 6

Next, the operations of calibration and analysis of channel occupancy are performed. In this case, the signal from the output of the generator 2 is fed through the channel switch 4 to the mixer 9, to the second input of which from the generator 3 receives a signal with a frequency below (or higher) the frequency of the generator 2 (for example, at 30 kHz). From the output of the mixer 9, the difference frequency (for example, 30 kHz) goes to the amplifier 10 and then to the analogue converter - code 11, from the output of which the sequence

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the pulses through the switch 5 is written to the input of the subtraction of the reverse register 6 and compared through the software block 1 with the sample present in the control block 8. If the deviation does not exceed the allowable, the device is recognized as intact and prepared for measurement.

Channel occupancy is determined by analyzing the level of the signal coming from the channel input through the channel switch 4 to the band-pass filter 12, which limits the level of spurious noise. The signal is then rectified by a quadratic detector 13, integrated by the integrator 14, and fed to the threshold unit 15. The trigger threshold of the threshold unit 15 is set above the noise level and lower than the signal level from the channel. The output signal of the threshold unit I5 causes the relay 16 to trip, in this case it is normal to close the contact 17, delaying the issuance of a command to the channel switch 4 and making measurements.

When the channel is empty, relay 16 does not operate and a measurement is taken. The software unit 1 issues a command to a 30 channel commutator 4 for connecting the output of generator 2 to the input of the measured channel and the output of the measured channel to the input of the mixer 9, to the switch 5 for connecting the output of the analog-code converter 11 to the addition input of the reversing register 6 and a device at the opposite end of the communication channel to perform similar switching.

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The result of the measurement is calculated from the reverse register 6 and through the program block 1 is fed to the block 7. The measurement of the channel at the following frequencies occurs the same

Formula inventions

Device for automatic measurement of frequency characteristics of communication channels by aut. St. No. 924876, which is such that, in order to increase the reliability of the measurement by excluding busy communication channels, sequentially connected band-pass filter was inserted into it,

the input of which is connected to the additional output of the channel switch, quadratic detector, integrator.

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the threshold unit and the relay, and the second output of the channel input switch of the software unit is connected to the second normally closed relay contact.

Claims (3)

Claim 4> Sheets and channel employment analysis. In this case, the signal from the output of the generator 2 passes through a channel switch 4 to a mixer 9, to the second input of which a signal from a generator 3 receives a frequency with a frequency lower (or higher) than the frequency of a generator 2 (for example, 30 kHz). From the output of the mixer 9, the differential frequency (for example, 30 kHz) is fed to the amplifier 10 and then to the converter analog - code 11, the output of which is the sequence An apparatus for automatic frequency characteristics of the measurements were Kan · ^so catch connection by the authors. St. No. 924876, which is distinguished by the fact that, in order to increase the reliability of measurements by eliminating busy communication channels, a series-connected bandpass filter is introduced into it, the input of which is connected to the additional output of the channel switch, a quadratic detector, an integrator, 3 1259498 4 threshold block and relay, and the second output to the input of the channel switch of the program block is connected to the second normally closed relay contact.