SU568174A2 - Apparatus for evaluation of noise immunity of communication channels - Google Patents

Description

(54) DEVICE FOR EVALUATING THE NOISE RESISTANCE OF CANADA COMMUNICATIONS

The invention relates to a technique of discrete messages, can be used in adaptive communication systems and for operational quality control of communication in the transmission of information using single and double phase modulation.

A device for estimating the noise immunity of communication channels is known, which contains input quadratures of the in-phase and quadrature channels, the outputs of which are connected to the inputs of one of the adders, the output of which through the accumulator is connected to one of the inputs of the second adder, and the functional converter. A rectifier connected in series, an additional drive and a quad and a signal-to-noise ratio meter are connected between the input of the common-mode quad channel and the output of the second adder, the output of the additional quadr is connected to the inerter input and the output of the signal-to-noise ratio meter to the input of the functional converter l.

However, the known device provides measurement retaliation with high accuracy and allows you to increase the pseudo-stability only in case of a sanity factor).

The purpose of the invention is to improve the accuracy of {jhovki noise immunity of communication channels.

For this purpose, an additional rectifier, a switch and a unit with a maximum amplitude definition and an additional functional converter and an output switch are connected in series to the device for estimating the noise immunity of the communication channels; the additional rectifier input is connected to the input of the quadrature channel input quadrant, the maximum amplitude determination unit is connected between the rectifier output and the additional accumulator input, the output of the signal-to-noise ratio meter is connected to the additional functional conversion input, and the functional output is connected to the second input of the output switch. transformist.

The drawing shows a structural electrical circuit of the device.

The device contains two input quadratures 1 and 2 of the in-phase and quadrature channels, rectifiers 3 and 4, adders 5, accumulators 7 and 8, a determining unit, an amplitude of amplitude 9, an additional quad 10, an inverter 11 measuring signal from the ground signal / interference 12, functional 1z and 14 converters, a key 15 and an output switch- 16.

Quad output 1,2 connected to the inputs of the adder 5, the output of which through the drive 7 is connected to one of the inputs of the adder 6, the inverter 11 is connected to the other input. Between the input of the quadrant 1 of the common-mode channel and the course of the adder 6 are connected in series rectifier 3 , block defined. nor maximum amplitude 9 drive 8, quad 10 and signal-to-noise ratio meter 12. Quad output 10 is connected to viBBepTopa ll and the signal-to-noise meter 12 output to the function transducer input. The input of the rectifier 4 is connected to the input of the quadrature of the quadrature channel 2, the unit determining the maximum amplitude 9; is connected between the output; the rectifier 3 It is the input of the accumulator 8. The output of the signal-to-noise ratio meter 12 is connected to the input of the functional converter 14, and the output of the functional converter 13 is connected to the second input of the switch 16.

The device for estimating the noise immunity of the rear channels works as follows.

With double phase and frequency modulation, the key 15 is closed, and the output switch 16 is in the lower position. In phase modulation, a signal from the in-phase output of the coherent demodulator and to another from the quadrature is sent to the input of the device; With frequency modulation, these inputs are fed from the frequency subchannels of the coherent frequency demodulator. If the two-phase modulation uses reference oscillations with shifts by 45, between the outputs of the demodulator and the inputs of the device, the wa switches include summing and subtracting devices, which is equivalent to rotating the reference oscillations by 45. Therefore, the outputs of the summing and subtracting devices are pred. The tapes are equipped with 11I (and the quadrature inputs of the proposed device for evaluating the noise resistance of the communication channels.

With the help of the quadruplers 1 and 2, the adder 5 and the accumulator 7, the average energy of the sum of the signal and interference is determined. Rectifiers 3 and 4 determine the absolute values of the input signals, most of which are allocated by the maximum amplitude determination unit 9. The average value of the output voltage of the block 9, obtained at the output of the storage device 8, is approximately proportional to the amplitude of the useful signal. determine the energy of the useful signal. The difference between the total energy of the signal and interference and the energy of the signal is determined by the inverter 11 and the adder 6. In the signal-to-interference ratio meter 12, the ratio of the output voltages of the quadrant 10 and the adder 6 is determined, which is approximately proportional to the signal / interference suppression. The functional transducer 14, the characteristic of which is different from the characteristic of the functional transducer 13, is preg; This output signal of the meter 12 to a voltage proportional to the measured noise immunity characteristic of the communication channels, which through the output switch 16 enters the output of the device.

Claims (1)

1. USSR author's certificate No. 518008, НО4 J 1/16, 1974.