SU576663A2 - Device for automatic control of communication channel state by noise level and overall attanuation - Google Patents

Description

inverter 13, delay circuit 14, element OR 15, limiter amplifier 1-6, driver 17 clock pulses, electronic switching stage 18, standby multivibrator 19, first amplifier 20 and second direct current amplifier 21, electronic connection circuit 22 electronic cascade , key amplifier 23, threshold noise level measuring unit 24, delay circuit 25 and measuring channel 26 of the intensity of impulse noise, containing series-connected threshold measuring unit 27 of impulse noise, element 28 and impulse noise counter 29, as well as block 30 time interval measurements, the output of which is connected to the second input of the counter 29, and the output of the distributor 9 is connected to the input of the threshold unit 27, and the output of the threshold unit 24 is connected to the second input of the element OR 28 drips 26, the output of the counter 29 is connected to the third input of the element OR 15, the inputs of the block 30 are connected respectively to the outputs of the first amplifier 20 and the second amplifier 21.

The device works as follows.

The control frequency, having a highly stable amplitude, is generated by generator 1, amplified by key amplifier 2 and amplifier m 3. Through filter 4, which is used to form the low frequency of the control and data channel, the control frequency is sent to the communication channel.

At the receiving side, the signal of the control frequency through the filter 6 and the preamplifier 8 enters the distributor 9, and after the distributor 9 multiplies in three directions.

Part of the signal through the open key-usnlitel 10 enters the threshold circuit And, the other part of the signal on the threshold unit 27, and a third part through the amplifier limiter 16 and the driver 17 enters the cascade 18.

A decrease in the level of the signal of the control signal above the donable values during a predetermined time leads to the appearance at the output of the element R1LI 15 of a signal about the failure of the communication channel.

The measurement of the impulse noise at the moment of sending the control frequency is provided by a constant block 27 permanently connected to the distributor 9, the threshold of response of which is calculated by the total signal level and the pulse number.

The electronic switching cascade is a frequency divider with a pre-selected division factor. At the end of the division by the impulse coming from cascade 18, the waiting multivibrator 19 overturns and by its potential through the first and second amplifiers 20, 21 closes the key amplifier 2, stopping the sending of the control frequency to the communication channel, the key amplifier

10, stopping the measurement of the signal level by the threshold circuit 11, and through block 30, the counter 29 is reset to a bullet state.

During the time spent in this state

of the waiting multivibrator 19, the level of the sound is measured by the threshold unit 24 (the key-amplifier 23 is opened by the potential removed from the first amplifier 20).

The threshold unit 24 is constructed in such a way that it also works from impulse noise. The number of actuations of this block through the OR element 28 is fixed by the counter 29. If the duration of the impulse noise or smooth noise exceeds the response time of the circuit 25, the output of the latter appears to be a fault signal of the communication channel in terms of the noise level that is transmitted through the OR 15 element to the circuit 22. When the standby multivibrator 19 returns to its original state, the measurement process is repeated.

Simultaneous connection to the communication channel of threshold measurement schemes 11 for residual attenuation on both sides at those moments

when a control frequency is sent to the communication channel, and the threshold units of the noise level measurement 24 are connected to the communication channel at those moments when the control signal in the channel is absent, cascades 18

electronic switching. The synchronism of their work is ensured by the operation of frequency dividers of switching stages 18, which impede the division of the reference frequency. To avoid "false synchronization,

Circuit 22 returns the frequency divider of cascade 18 of the electronic commutation to the initial (“zero”) state every time when the control frequency is removed or disappears. In order to limit the possibilities of unjustified determination of the malfunction of the communication channel during short-term interruptions or the occurrence of short-term noise amplifiers, circuits 14 and 25 are used that act as the analyzer for the duration of the interruption of the communication channel and the analyzer for the duration of the sound.

Since the control frequency is not supplied to the communication channel at the moment of noise measurement, the threshold circuit 11 will respond to this,

as a fault in the communication channel. Therefore, a buffer cascade 12 is provided, to which, at the time of measuring the noise from the first amplifier 20, a locking potential is applied. The fault signal of the communication channel, fixed by the threshold circuit 11, is connected via the buffer cascade 12, the inverter 13, connected in series, the circuit 14 is fed to the input element OR 15. The malfunction signal of the communication channel, detected by the threshold unit 24, is fed through the circuit 25 to the input element OR 15.

When filling for a certain time counter 29 channel failure signal

The connection enters the input element OR 1B.

Claims (1)

Invention Formula A device for automatically monitoring the state of a communication channel by noise level and residual attenuation by aut. St. 277021, characterized in that, in order to improve the control accuracy, a channel for measuring the intensity of impulse noise is inserted, containing a series-connected threshold unit for measuring impulse noise, an OR element and a pulse counter, as well as a unit for measuring time intervals whose output is connected to the second input impulse noise counter, the output of the power distributor is connected to the input of the threshold unit for measuring impulse noise, and the output of the threshold unit for measuring the noise level is connected to the second input of the OR element measuring the intensity of impulse noise, the output of the impulse noise counter is connected to the third input of the OR element The time interval measuring unit is connected to the outputs of the first and second DC amplifiers, respectively.