A method and coder for baseband channel NRZ code stream to unipolar code stream conversion

Abstract

The invention discloses a method which is used to transform the base band channel diszeroization binary system NRZ code flow to unipolarity and encoder. The HDB3 pre-coding circuit and CMI code circuit are formed to encoder to transform data current code pattern. The HDB3 pre-coding circuit utilizes the input clock signal to transform the NRZ code flow to HDB3 code flow, and correspondingly outputs V code indication information, B code indication information, B code polar indication information, and start code circuit indication information to CMI code circuit. The CMI code circuit reverses CMI code rule according to the coding identification to transform the indication information to code flow with composition CMI format to output. The method and encoder can realize the transformation function of the CMI coding with HDB3 pre-coding; moreover, the hardwired connection is simple and reliable, the transformed code flow is without spike.

Description

technical field [0001] The invention relates to a baseband data signal processing technology in a communication system, in particular to a method and an encoder for converting a non-return-to-zero binary NRZ code stream into a unipolar code stream in a baseband channel. Background technique [0002] In the field of baseband data signal processing technology, generally, the coded logo inversion CMI code pattern with third-order high-density bipolar HDB3 precoding is simplified to HDB3+CMI code pattern. The CMI encoder with HDB3 precoding is mainly used in communication baseband encoding, and is used to realize the conversion of unipolar non-return-to-zero NRZ pattern data signals into data streams in HDB3+CMI pattern format. The HDB3+CMI encoding method has the advantages of both the HDB3 code pattern and the CMI code pattern. [0003] The reverse CMI code of the coding mark is the quaternary group interface code pattern specified by CCITT, and the third-order high-density b...

AI Technical Summary

Problems solved by technology

Since the HDB3 encoding method proposed in the above-mentioned HDB3 encoding-related patents is to convert the NRZ code stream into a bipolar code stream, the CMI encoding method proposed in the CMI encoding-related patent is to convert the NRZ code stream into a unipolar code stream, so directly Combining the HDB3 encoder and the CMI encoder proposed in the above patent cannot realize the CMI code conversion function with HDB3 precoding

Therefore, the method of citing the above patent cannot directly realize the NRZ code stream to be pre-encoded by HDB3, and then perform CMI code conversion function

Images