SU479261A1 - Communication control device - Google Patents

Description

one

The invention relates to data transmission, in particular, to data transmission equipment with amplitude and amplitude-phase modulation.

A device for controlling a communication channel is known, comprising receiving and pilot amplifiers with gain control circuits, an output switch, a device for monitoring the level of the received signal, and a channel status indicator.

However, in the known device there is no control over the level of received signals at the boundaries of a given range while decreasing or increasing the level of these signals is above the permissible norm.

The purpose of the invention is to improve the quality of control of the received signal level.

For this, the output of the automatic gain control circuit detector is connected to the input of a two-level level comparator, the output of which, in turn, is connected to a control input of a valve connected to the output of the communication channel.

The drawing shows a block diagram of the device.

The device for monitoring the communication channel contains amplifiers 1.2, respectively, of the received signal and the pilot signal with gain control circuits, consisting of a regulating element 3, the control input of which is connected to the output of the detector 4 of the automatic gain control circuit (AGC) and the output is with the input of the amplifier of the received signal 1, the series-connected load of the AGC 5 and the filter of the pilot signal 6, while the input of the load of the AGC

5 is connected to the output of the amplifier. Received signal 1, and the output of the filter pilot signal

6- to the input of the pilot-signal amplifier 2, the output of which is connected to the input of the AGC detector 4;

an output switch (valve 7), the input of which is connected to the combined load of the AGC load 5 and the input of the pilot signal filter 6, is a two-level level comparator 8, through

time delay block 9 connected to the drip state indicator 10. The output of the AGC detector 4 is also connected to the control input of the pilot signal amplifier 2 and to the input of the comparator 8, the output of which is connected to the control input of the valve 7 and is the signal output of the device. The outlet of the valve 7 is the information output of the device, and the input of the regulating element 3 is the input of the device.

The device works as follows.

Information (input) signals from the device through the regulating element 3 with

varying level. entering the input

variable gain depending on the magnitude of the signal at its control input, passes to the amplifier of the received signal 1, from the output of which the amplified signals through the load of AGC 5 are fed to the inputs of the valve 7 and the pilot signal filter 6. Vibrations with the frequency of the pilot signal, extracted from the spectrum of information signals, amplified by the pilot-signal amplifier 2 and, rectified by the AGC detector 4, in the form of DC voltage are fed to the control input of the regulating element 3, I act on it in such a way that Even if the input signal is used, its transmission coefficient decreases; if it is small, it increases. As a result, the level of information signals at the inputs of the valve 7 and the filter of the Pilot signal 6 is maintained close to constant, despite the change in the level of the input signals over a wide range. In case the pilot signal level goes beyond the acceptable range from below or from above, the level 8 comparator will work, turn on the time delay block 9 and at the same time generate the forbidden potential for the controlled INPUT of valve 7, the latter will close and prohibit the passage of distorted information signals to the information output (to a confidence increase device). On

the alarm output of the device according to the channel malfunction signal. After the time determined by the time delay block 9, the indicator 10 will visually show the failure of the communication channel. When the normal information signal level is restored, the device is again ready to receive this information, while the time delay block 9 is turned off and the channel fault indication disappears.

Subject invention

A communication channel control device containing amplifiers of the received and pilot signals with gain control circuits, an output switch, a device for monitoring the received signal level and a channel state indicator, characterized in that, in order to improve the quality of the received signal level, the output of the circuit detector the automatic gain control is connected to the input of a two-level level comparator, the output of which, in turn, is connected to the control input of the valve connected at the outlet of the communication channel.