SU436449A1 - DEVICE FOR MONITORING LEVELS OF SIGNALS IN TELEPHONE CHANNELS OF COMMUNICATION SYSTEMS - Google Patents

Description

one

The invention relates to signal transmission monitoring systems and is intended for the on-line monitoring of the mode of multiple access to a repeater in a telephone trunk of a small-channel satellite communication system, organized by means of frequency multiplexing of telephone messages at a standard intermediate frequency of 70 + 17 MHz and including 7U telephone channels . Each telephone message in the trunk is transmitted on a separate carrier by applying the appropriate type of modulation.

A device for monitoring signal levels in telephone channels of communication systems is known, comprising a path for allocating a narrowband portion of the spectrum, including a modulator, a smoothly-ranging band oscillator, a narrowband filter, a detector and a low-pass filter, a threshold level setting system, a dial-up oscillator frequency control system, which includes a sawtooth generator, a sawtooth generator control device, a Schmitt trigger and a deflecting relay. In addition, the device contains electronically controlled step switches, time relays and a light signaling system for measurement results.

Multiple access to a satellite transponder requires power control

earth station transmitters for aligning at the repeater input the carrier levels in all trunk telephone channels according to the level of the pilot signal emitted by one of the network stations. In the absence of equality of levels, the transponder is overloaded with signals from some stations, which makes it difficult or impossible to receive signals from other stations of the network.

However, in a known device, detection of an overload signal in a channel is achieved by monitoring the intensity of the FM signal spectrum, rather than by isolating and analyzing the carrier level, which

must have a specified value during normal channel operation; in addition, it is impossible to determine whether there is a steady overload in several (in all channels) of the group tract or only in one channel

and it is impossible to determine the number of the faulty channel; The overload indicator lamp corresponding to this group path is on until the station operator manually extinguishes it. Consequently, in subsequent reviews of this group tract, no new information can be obtained from the spectrum of telephone communications, and, in particular, an indication of the presence of a non-load signal cannot be automatically cleared; In a known device, there is no record of the time of detection of a fault in the group path.

In order to increase the accuracy and operational control of the carrier level, the device additionally introduced a comparison circuit of the logical node, frequency tuning control node, documentary recording node, and display node, while the output of the carrier level extraction path of the analyzed channel is connected through a comparison circuit connected to the path output allocation of the carrier level of the pilot signal, to one input of the evaluation logic node, to the other input of which the output of the strobe pulses of the control node is reconstructed frequency, and the cert output of the evaluation logic node is simultaneously connected to the first inputs of the frequency tuning control node, the document recording node and the display node, the second output of the evaluation logic node to the second input of the display node, to the third input of which the second input of the documentation node is connected, the second output of the frequency control control unit and the second inputs of the electronic switch and the path extraction path of the analyzed channel, the third input and output of the frequency control control unit being connected En respectively to the exit and the third input of the documentary record node; the frequency control node includes a series-connected electronic clock, a stop and start counting unit, a delay circuit and a digital counter; The documentary recording unit includes serially connected code information conversion unit and c. printing press unit; the display unit includes serially connected display unit control unit and display board.

The drawing is a block diagram of the proposed device for controlling the levels of signals in telephone channels of communication systems.

The device is connected to the outputs of the receiving group paths of the channel-forming equipment, which carry out frequency division into groups (each group can consist, for example, of ten channels) and convert all channel groups from the standard intermediate frequency / u 70 ± 17 MHz to a lower intermediate frequency / n, (for example, fn, 6 ± 0, in MHz).

The device contains an electronic switch 1, the path 2 of the allocation of the carrier level of the analyzed channel, consisting of mixer 3, band generator 4 discrete frequency tuning 4, intermediate frequency amplifier 5, mixer 6, reference generator 7, concentrated selection filter 8, intermediate frequency amplifier 9 , amplitude detector 10, low pass filter 11, path 12 of the selection of the pilot carrier signal, comparison circuit 13, which compares the level of the carrier of the analyzed channel with the level of the pilot-signal carrier logic, 14, evaluating the comparison result and issuing a response in the form of signals "Norm or" Not norm. The device also includes an electronic clock G5, generating clock pulses and setting the time of a single analysis of the carrier level in the channel, node 16 for stopping and counting, interrupting the arrival of clock pulses from the electronic clock 15 after the "Not normal output of the logic node 14" signal appears. , delay circuit 17, creating gating pulses, after which they arrive at logic node 14, the latter evaluates the carrier levels; digital pulse counter 18, with the clock 15, node 16, circuit 17, and counter 18 constituting the frequency tuning control node 19. The input of the counter 18 receives the clock pulses from the output of the delay circuit 17,

and from the output of the counter, the signal is fed to an electronic switch 1, a generator 4, a code information conversion unit 20, a digital printing unit 21, which is triggered by a "Not normal" signal and registers the number of the faulty channel received from the code information conversion unit 20, And the time (accurate to a minute) of the signal "Not the rate received from the electronic clock 15, but upon completion of registration sends a signal to the node 16 to stop and start the counting, which resumes the arrival of clock pulses to the delay circuit 17. Moreover, blocks 20 and 21 constitute unit 22 of the documentary record.

In addition, the device contains a display control unit 23, the three inputs of which receive signals "Normal or Not normal from the output of logical node 14, respectively, and information about the number of the analyzed channel from the output of pulse counter 18, each of whose outputs is connected to the corresponding element of the information board 24, intended for fixing the numbers of the channels, the carrier levels in

different from the pilot carrier level; blocks 23 and 24 constitute the display unit 25. Using a mixer 3 and a band oscillator 4 with discrete frequency tuning, the spectrum of the channels of the analyzed group is sequentially converted to a constant intermediate frequency / pz, moreover, to ensure the overlap of the frequency range occupied by the group of channels and reducing the level of Raman noise fn, should be selected several times higher than the frequency f (for example, n ZOMHz).

To ensure effective channel filtering using a mixer 6, a reference oscillator 7, and a filter 8, another transformation of the frequency spectrum of the analyzed channel is carried out to a sufficiently low intermediate frequency fn. (for example, fn4 2 MHz).

The amplifier 9, the amplitude detector 10 and the filter 11 are used to amplify, detect and isolate the carrier level.

Since in carrier pauses the carrier is suppressed and the telephone service Lisch is 25–30% of the time he is occupied by the correspondent, the electronic clock determines the duration of a single analysis of the carrier level in the channel so that the average telephone time message equal to 4 min, the probability of obtaining information about the level of the carrier in the channel P, is calculated by the formula

t

Ш6

P l-d-T)

where 7 is the average activity of the telephone channel; T is the average duration of the body; background;

t is the total number of channels in the trunk; b duration of a single analysis

The channel is close to 1.

If, for example, there are 200 telephone channels in the trunk and the time of a single analysis of the carrier level in the channel is equal to 100 ms, and the entire period of the survey of the trunk is 20 seconds, then 995.

In connection with the suppression of the “carrier” that is in a pause when analyzing a telephone channel, the following situations are possible: the situation “The rate at which the carrier level in the channel is approximately equal to the level of the pilot carrier signal; Situation "Not the rate at which the carrier level in the channel is less or more by a certain amount of the pilot carrier signal level; Situation "Noise, in which either the channel is not occupied at all, or the channel behind" t, but at the time of analysis the carrier was suppressed.

After a situation is detected in the channel, the “Not Normal” channel number is displayed on the information board. If on subsequent reviews of the trunk in this channel the situation is not the norm or noise, the channel number display on the scoreboard is preserved, if the situation the norm appears in the channel, the channel number display on the scoreboard is stopped.

Such an algorithm of operation of the control unit of the Display System allows, on the one hand, to automatically remove erroneously obtained information about the situation, “It’s not the norm in the channel and thus actually carry out continuous monitoring of the carrier level, on the other hand, to automatically release the panel element corresponding to this channel from the preceding information, when the channel is transmitted by the correspondent control system of another station.

Since the invention is intended to control multiple access in a telephone trunk with loose channels, information about the channel number in which the situation is not normal and the time when this situation is detected in the form of a request comes from qi (print device 21 to the telephone trunk control equipment) From the control equipment, the number of stations to which the faulty channel belongs at a specified time is transmitted to the digitizer 21.

Subject invention

Claims (4)

1. A device for controlling the levels of signals in telephone channels of communication systems containing an electronic switch, the output of which is connected to the input of the path selection path of the analyzed channel as well as the path. leveling pilot carrier signal, in order to increase the accuracy of the operational control of carrier levels, additional comparison scheme, evaluation logic node, frequency tuning control node, document recording node and indication node were introduced, and the level allocation path output The carrier of the analyzed channel is connected through the comparison circuit connected to the output of the path of the carrier level of the pilot signal to one input of the evaluation node, to the other input of which the output of the "strobe pulses frequency tuning control node, and the first output of the evaluation node is simultaneously connected to the first inputs of the frequency tuning control node, the documentary recording node and the display node, the second output of the evaluation logic node to the second input of the display node, to the third the input of which is connected to the second input of the documenting recording node, the second output of the frequency tuning control node to the second inputs of the electronic switch and the carrier level extraction path of the analyzed channel, the third input and output of the frequency tuning control node are connected respectively to the output and the third input of the documenting recording node. 2. The device according to claim 1, characterized in that the frequency control node includes a series-connected electronic clock, a stop and start counting unit, a delay circuit and a digital counter. 3. A device according to claim 1, wherein the documentary recording unit includes serially connected code information converting unit and a digitizer. 4. The device according to claim 1, characterized in that the display unit includes serially connected display control unit and display panel.