SU1425855A1 - Device for inspecting communication channel quality - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to improve the accuracy of control. The device comprises a matching unit 1, a unit 5 extraction of a monitored parameter, including a root-mean-square converter 6, r-7 linear-varying voltage, an amplitude selector 8, a counter 9 errors, r-r 10 quantizing pulses. To achieve the goal, a noise extraction unit 2 is inserted into the device, including a frequency selector 3 and 4, a one-shot 11, a delay element 12, a register 13, and a control block 14. To provide the necessary control accuracy, the entire range of values of the monitored parameter is divided into several subranges, for example, into two: upper and lower. The subband change is made by changing the coef. Transmitting 4 through a signal from block 14 containing a comparator 15 and a T-flip-flop 16. Comparator 15 has two thresholds N and N corresponding to the extreme values of counter 9, at which a given control accuracy is ensured. 2 3. p. F-ly, 2 ill. (L

Description

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The invention relates to electro-SOS and can be used to control the quality of communication channels by noise level in an unloaded frequency band.

The purpose of the invention is to increase the accuracy of the control.

FIG. 1 shows the structural electrical circuit of the proposed device; in fig. 2 - timing diagram of the amplitude selector.

The device for monitoring the quality of the communication channel contains a matching unit 1, a noise extracting unit 2 including a frequency selector 3 and an amplifier 4, a monitoring parameter extracting unit 5 including a root-square converter 6, a generator 7 linearly varying voltage axis, and amplitude selector 8, counter 9 errors, generator of 10 quantizing pulses, one-shot 11, element 12 delay, register 13, control block 14, including a two-threshold comparator 15 and T-trigger 16, indicator 17.

The device works as follows.

The input signal is fed to block 1, which is intended to match the device with the communication channel to the resistance, and then to the block, in which the signal is suppressed and noise is extracted with the help of a frequency selector 3. The noise introduced is amplified by amplifier A. For the selection of noise, for example, the upper frequencies of the radio-frequency group path are used. stations not occupied by the group signal, and / or parts of the spectrum between the channels of the tonal frequency.

The amplified noise is fed to the converter 6, the output voltage of which is proportional to the rms value of the noise. This voltage is supplied to the threshold input of the amplitude selector 8, to the signal input of which is applied linearly varying, for example, triangular (Fig.2), the voltage from the generator 7, which sets the duration of the TC measurement session.

Lecturer 8 are formed by rectangular pulses of logic levels with a period of following T, which are fed to the control input of the counter 9 and to the one-shot 11.

The signal at the control input of the counter 9 sets the mode of its operation. For example, the logical unit at the control input of the counter 9 corresponds to the addition mode, to the logical zero to the subtraction mode. The signal input of the counter 9 is pulsed from the generator 7, the follow-up period of which

,

In the absence of interference in the channel, the noise level at the device input is the threshold voltage of the amplitude selector 8 approximately equal to zero (Fig. 2S), and the signal duty cycle at the output of the amplitude selector 8 (FIG. 2b) is equal to two. In this case, at the end of the measurement session, the content of the counter 9 is equal to zero, since the operation time for addition is equal to the operation time for subtraction.

If there is interference in the channel or the connection is broken, the noise level in the channel increases, while the threshold voltage is greater than zero (figure 2 g), and the signal duty cycle at the output of the amplitude selector 8 (figure 2) is not equal to two, i.e. prevail over. As a result, over time, counter 9 counts the number of pulses equal to

N TKB

with about

0

five

where IT is the prevailing value.

The contents of the counter 9 from its outputs are fed to the information inputs of the register 13 and the signal inputs of the two-threshold comparator 15.

To ensure the required control accuracy, the entire range of values of the monitored parameter is divided into several subranges, for example, into two: upper and lower. Changing the subbands ec by changing the transmission ratio of amplifier 4 according to the signal from block 14 containing comparator 15 and T-flip-flop 16. Comparator 15 has two thresholds N, and N, j corresponding to the extreme values of counter 9, at which the specified control accuracy is ensured . At the end of the measurement session, the single-vibrator 11 forms a short pulse that is applied to the gate input of the comparator. The contents of counter 9 at this point should be in the zone between N and N. If after the end of the measurement session N N

(work in the subrange) or N N, (work in the upper subrange), the comparator 15 detects the pulse by which T flip-flop 16 changes its state to the opposite. The signal from the latter is fed to the control inputs of the comparator 15 and the amplifier 4, as well as to the senior information input of the register 13, specifying the operating subband. For example, a logical zero at the output of the T-flip-flop 16 corresponds to the inclusion of the lower sub-band, a logical one - the inclusion of the upper sub-band.

At the same time, the signal from the one-oscillator 11 is fed directly to the clock input of the register 13 to record the contents of the counter and the T-flip-flop 16 into it, and through the delay element 12 to the zero reset of the counter 9.

Thus, the contents of register 13 depend on the noise level at the input of the device and uniquely reflect the quality of the communication channel. The contents of register 13 from its outputs are fed to indicator 17.

Claims (3)

1. A device for monitoring the quality of the communication channel, containing a matching unit, a selection unit for the monitored parameter, an indicator and a serially connected quantizing pulse generator and an error counter, characterized in that, in order to monitor the control accuracy, the serially connected single vibrator and the delay element are introduced , a serially connected control unit and a register, as well as a noise elimination unit, the states of 1 serially connected frequency d 5 0 five 0 five 0 selector and amplifier, while the output of the matching unit is connected to the frequency selector input, the amplifier's input is connected to the single-vibrator input and to the control input of the error counter, the outputs of which are connected to the corresponding signal inputs of the control unit and the corresponding information inputs of the register, outputs which are connected to the corresponding inputs of the indicator, the output of the one-shot is connected to the clock input of the register and to the gate INPUT of the control unit, the output to It is expensively connected to the control input of the amplifier, and the output of the delay element is connected to the zeroing input of the error counter. 2. A device according to claim 1, characterized in that the block; the monitored parameter is made in the form of a linearly varying voltage generator and an amplitude selector connected in series, the threshold input of which is connected to the output of the RMS converter whose input is the input of the controlled parameter selection unit whose output is the output of the amplitude selector. 3. The device according to Claim 1, characterized in that the control unit is complete in the form of series-connected :: two-threshold comparator and T-flip-flop, the output of which is connected to the control input of the two-threshold comparator, the signal and test inputs of which are respectively signal and gating inputs of the control unit, the output of which is the output of the T-flip-flop. V l / FIG. 2