SU786058A1 - Television signal coding device - Google Patents

Description

This invention relates to the field of communications.

A device for encoding a television signal is known, which contains an analog-to-digital converter (ADC), whose outputs are connected to the inputs of a signal analysis unit, a coding changing unit, the first input of which is connected to the output of the signal analysis unit, and the second input to the clock generator output, a coding unit , the first control input of which is connected to the clock generator through the pulse distributor, and the second and third control inputs with the first and second outputs of the mode changing unit is coded and, and a code group formation unit, the signal inputs of which are connected to the ADC outputs, the control inputs are connected to the clock generator output, and the outputs of the code group generation unit are connected to the signal inputs of the coding unit {I.

However, in such a device, the level of distortion is great.

The aim of the invention is to reduce distortion.

For this purpose, in the proposed device, the coding mode changing unit is made in the form of serially connected shift register, OR element and inverter. The first input of the shift register is connected to the output of the signal analysis unit, and the second input to the output of the clock generator. The coding unit is made in the form of serially connected elements 2I-OR and a register of the formation of code combinations. The control input of the register 10 forming coding combinations is connected to the output of the pulse distributor, and the inputs of the 2I-OR elements to the outputs of the code group formation unit and to the outputs of the OR element and the inverter of the coding change unit, with the output of which

IS is also connected to one of the inputs of the register for the formation of coding block code combinations.

The drawing shows a structural electrical circuit of the proposed device.

The device contains ADC 1, block 2

20 forming code groups, signal analysis block 3, pulse distributor 4, coding block 5 consisting of elements 2ILI 6 and register 7 forming code

combinations, a coding mode changing unit 8, consisting of a shift register 9, an OR 10 element and an inverter 11, and a generator of 12 clock pulses.

The device works as follows.

The input analog video signal is fed to the input of the ADC, which converts the original analog video signal into an eight-bit code. Unit 3 generates a sign-in case of detection of signal portions corresponding to the transmission of the fine-structured components of the image. Otherwise, G 0 is generated.

In the first cycle of operation of the device, the first code word is recorded in the first code into the first register of block 2 and the sign in the first digit of register 9. In the second cycle, the information from the first register of block 2 is rewritten. A shift is made by one bit in register 9, the next code word is written into the first register of BLACK 2 and the corresponding attribute in the first bit of register 9. The device works in the third cycle in the same way, at the end of which a group of three code words stored in the registers of block 2, and the combination of the three features corresponding to these code words in register 9. To reduce distortions in the transmission of the fine structure components of the signal, an element OR 10 is introduced, which provides priority for the transfer of small parts her. Let at least one of the signs recorded in register 9 be equal to “1, i.e. there is a small detail. The signal corresponding to the logic level “1, through the element OR 10 enters the elements 2И-OR 6.

This signal permits the recording of information from the upper bits of the registers of block 2 through elements 2I-OR 6 to register 7. Thus, the code word corresponding to the first coding mode is generated. If all the signs are equal to "O, the output of the inverter 11 produces a signal corresponding to the logic level" 1, which allows writing from the last register of block 2 through elements 2I-OR 6 to register 7. Thus, the code word corresponding to the second encoding mode is formed.

To transmit information about the used coding mode, the tenth bit of register 7 is entered into the mode indication, for which the output of the element OR 10 is connected via inverter 11 to the input of the tenth tenth register bit 7.

The synchronization of the operation of the device is provided by the generator 12. The distributor 4 serves to provide a pulse that permits the writing of code words to the register 7.

The proposed device allows reducing the volume of a digital television signal to 3.3 bits per sample at an image quality that meets the standards of the broadcast television.

Claims (1)

An apparatus for encoding a television signal, comprising an analog-to-digital converter, the outputs of which are connected to the inputs of a signal analysis unit, a coding changing unit, the first input of which is connected to the output of a signal analysis unit, and the second input is connected to a clock generator output, a coding unit , the first control input of which is connected to the clock pulse generator through the pulse distributor, and the second and third control inputs are connected to the first and second outputs of the mode changing unit in coding, and a code group formation unit, J signal inputs of which are connected to the outputs of the analog-to-digital converter, the control inputs with the output of the clock generator, and the outputs of the code group formation unit are connected to the signal inputs of the coding unit, 0 characterized in that, in order to reduce. no distortions, the coding mode changing unit is made in the form of serially connected shift register, OR element and inverter, the first input of the shift register is connected to the output of the signal analysis unit, and the second input is connected to the output of the clock generator, and the coding unit is made in the form of serially connected elements 2I-OR and the register of the formation of code combinations, the control input of the register of the formation of code combinations connected to the output of the distributor HMnyvibcoB, and the inputs of the elements 2I-OR connected to the output s block code groups and forming with the outputs of the OR gate and an inverter unit change of coding modes, wherein the yield of the inverter is also coupled to one input of the register code generating unit coding combinations. oInformation sources, taken into account in the examination I. "Technique of cinema and television, 1977, no. 9, p. 52-54 (prototype).