SU1626397A1 - Digital data transmission system - Google Patents

Abstract

The invention relates to electrical and radio communications and may be used in voice transmission systems. The aim of the invention is to increase noise immunity by reducing the noise level. The device contains the receiving and transmitting terminal equipment 1, digital eccentricizer 2, regeneration Item 3, control block 4, receive path block 5, key 6, combining block 7, switch 8, control pulse generator 9, forward 10 and reverse 11 channels connection. The imaging unit 9 forms at its output a sequence consisting of seven zeros and one, which increases the signal-to-noise ratio in the channels of digital transmission systems. 1 il.

Description

The invention relates to electrical and radio communications and can be used in voice information transmission systems.

The purpose of the invention is to increase noise immunity by reducing noise.

The drawing shows a structural diagram of a digital transmission system.

The transmission system contains a terminal equipment 1 for receiving and transmitting, a digital echo suppressor 2, a regeneration station 3, a control unit 4, a receiving path unit 5, a key 6, an association unit 7, a switch 8, a control pulse train driver 9, a direct 10 and a return 11 kang communication.

The transmission system is as follows.

From the output of the equipment 1, the digital signal is sent to the output of the digital echo suppressor 2, processed and fed to the output of the digital echo suppressor 2, from which, passing through the direct communication channel 10, is fed to the input of the regeneration point 3. The recovered signal from the output of the regeneration point 3 is received further in line. In the process of signal recovery in the regeneration point 3 is the selection of clock signals. In the reverse direction of transmission, the signal from the reverse communication channel 11 enters the second input of the regeneration point 3, OCCTaHaBAHBaeTCfl, while the clock signals are extracted, and from the second output of the regeneration point 3 is fed into the line and fed to the second input of the digital echo suppressor

2. it is processed and from the second output of the digital echo suppressor 2 it is supplied to the corresponding input of the terminal equipment

1.

The signals supplied to the digital echo suppressor 2 are processed as follows. The control unit 4 analyzes the information signals arriving at its first and second inputs, determines the operation mode of the digital • air conditioner 2 and generates control signals at its outputs, which are fed respectively to the unit 5 of the receiving paths and switch 8. If there is a control signal from unit 4, the unit 5 introduces a 6 dB attenuation into the serial PCM signal, which is necessary to reduce the effect of the electric echo effect during the oncoming conversation.

If there is a control signal from block 4, the transmission path introduces a attenuation of more than 55 dB into the serial digital PCM signal to prevent the propagation of the echo signal in the opposite direction of transmission and eliminate the interfering effect of the electric echo. This is as follows. In the absence of a control signal from block 4 at the input of the switch 8, there is no inhibitory signal at the input of the key 6. In this case, the digital signal supplied to the input of the key 6 goes to the output of the digital echo suppressor 2 without changes.

When a control signal appears at the input of the switch 8, a control signal appears at its first output, which, entering the input of the key 6, prohibits the passage of a digital signal to the output. Then, a control signal appears at the second output of the switch 8, which enables the operation of the driver 9. The driver 9 generates a sequence consisting of seven zeros and an eighth unit at its output. This sequence (00000001) is fed to the second input of the combining unit 7 and then to the output of the digital echo suppressor 2.

Claims (1)

Claim A digital transmission system comprising terminal transmission and reception equipment connected in series with a forward and reverse transmission channels, a digital echo suppressor and N regeneration points connected in series, the digital echo suppressor containing a key, the input of which is connected to a direct communication channel, a receiving path unit included in the reverse communication channel , and a control unit, the first and second inputs of which are connected respectively to the inputs of the forward and reverse communication channels, and the first output is connected to the control input of the unit A receiving path, characterized in that, in order to increase the noise immunity by reducing the level of 'plague', a series-connected switch, a shaper of the control pulse sequence and a combining unit, the second input of which is connected to the output of the key, the second input of which is connected to the second input, are combined into a digital echo suppressor a switch, the input of which is connected to the second output of the control unit, and the output of the combining unit is connected to the output of the direct communication channel.