SU553755A2 - Device to control the number of errors in the transmission channels of discrete information - Google Patents

Description

the output of the OR circuit, the second input of the second circuit AND to the output of the inverter, and the outputs of the AND circuits are connected to the inputs of the display unit, a pulse response shaping unit, a threshold block and a switch are inserted, with a pulse response shaping unit connected between the input node and the multiplier information input , the output of the automatic gain control unit through one of the switch circuits is connected to the control input of the amplifier for measuring additive interference, and the outputs of the threshold unit through other circuits of the switch are connected respectively, to the amplitude selectors of the channels measuring additive noise and interruptions.

FIG. 1 shows a functional diagram of the device; in fig. 2 - time diagrams that show his work.

The device contains an input node 1, a series-connected amplifier 2 and a multiplier 3, the information input of which is connected to the input of amplifier 2, connected to the output of multiplier 3, a channel for measuring additive interference 4, consisting of a series-connected low-frequency filter 5, amplifier 6, linear detector 7 , an amplitude selector 8 and a pulse width generator 9, and a ka, to measure interruptions 10, consisting of a series-connected high-frequency filter AND, an amplifier 12, a linear detector 13, a lower filter frequency 14, amplitude selector 15 and inverter 16; an automatic gain control unit 17, the input of which is connected to the output of amplifier 12 of the channel for measuring breaks 10; the OR 18 circuit, the inputs of which are connected to the outputs of the pulse width generator 9 and the inverter 16, a quantizing pulse generator 19 connected to the first inputs AND 20 and 21, the second input of the AND circuit 20 connected to the output of the OR circuit 18, the second input of the AND 21 circuit to the output of the inverter 16, and the inputs of the circuits And 20 and 21 are connected to the inputs of the display unit 22; impulse response generating unit 23, threshold unit 24 and switch 25. At that, impulse response generating unit 23 is connected between input node 1 and information input of multiplier 3, output of automatic gain control unit 17 through one of the circuits of switch 25 is connected to control input of amplifier 6 the channel for measuring additive noise 4, and the outputs of the threshold unit 24 through other circuits of the switch 25 are connected respectively to amplitude selectors 8 and 15 of the channels for measuring additive noise and interruptions 4 and 10.

The device works as follows.

From the communication channel, the signals of the meander type pulse sequence (Fig. 2a), through the input node 1, enter the pulse response shaping unit 23. The input

the node serves to match the device on the input with the communication channel.

The impulse response shaping unit 23 operates in shock excitation mode. Under the action of the edges of a rectangular periodic signal (Fig. 2a), the op generates responses consisting of alternating current pulses (Fig. 26), i.e., free oscillations arise from the action of each edge of the rectangular periodic signal. The frequency of these oscillations is equal to the average frequency of the passband of the impulse response formation unit 23, and the envelope is measured according to the law determined by the amplitude-frequency characteristic of the latter.

Under the influence of interferences n breaks in the communication channel in a periodic rectangular signal, the positions of its fronts are shifted in time (Fig. 2, e, g, i).

If the front offset is such that at the time of gating the polarity of the received parcel changes with respect to the transmitted one, an error is generated.

In the device, the fronts of the i-periodic signal correspond to the displacement of the position of the responses of the block forming the impulse response 23 on the time axis (Fig. 2 g, e, 3, and).

An error at the reception occurs if the duration T of the interval between the outliers of the response envelopes at a given threshold level d in amplitude of the response exceeds a certain value of mp. (Fig. 2e, d), or the emission of the response envelope will cross the threshold level in amplitude of a certain value c (Fig. 2 g, h). In most cases, only the value of m changes due to the effect of additive interference.

Errors from additive hindrances and interruptions are distinguished by the magnitude of the threshold level.

Tpor ..

The width of the strobe pulse (Fig. 2a) determines the correcting capacity of the receiver. According to the known corrective

the ability of the receiver to set the required thresholds tpor. and c. To set thresholds, as well as to change them in order to increase accuracy in device operation modes according to the signal

AC and at other values of the speed and power of the signal applies the threshold unit 24.

The impulse response generating unit 23 can be tuned to the bandwidth of the partial channel in a multi-channel communication system. In this case, the device is used to monitor the multi-channel path by statistically estimating the number of faults in a separate channel.

The setting of various threshold values in the amplitude selectors 8 and 15, as well as the disconnection of the automatic gain control unit 17, is carried out using the switch 25.