CONVOLUTIONAL METRIC FOR DIGITAL SIGNAL PROCESSING

The method of combat intersymbol interference in the transmission of digital signals over multipath channels. Analyzed the use of convolutional codes for encoding and deco-coding messages. To combat intersymbol interference proposed an approach based on the modifi cation of the «soft» Viterbi decoding. Modifi cation of this algorithm is that, if before using lattice diagram of states and transitions, each branch of the lattice indicating a few characters in the modifi ed method, each branch of the transition of a specifi c state (code word) in another state indicating a single current character. Consider the question of using the quadratic metrics in the convolution procedure, and show that their use makes it possible to improve the noise immunity of up to 0,5 dB. As a result of it was found that the delay recovery transmitted sequence of symbols is only slightly dependent on the ratio of «signal/noise» and considerably depending on the combination of parameters intersymbol interference. Simulation results of the described method.