Mismatched DPCM encoding of autoregressive processes
A method for computing the mean squared error distortion of differential pulse code modulation (DPCM) applied to Gaussian autoregressive sources is developed. This extends previous work wherein the code predictor was matched to the source. A two-dimensional version of the projection method for the computation of the stationary distribution of the joint source-state process is developed from which distortion can be readily evaluated. An iterative algorithm is used to optimize the quantizer for a given source and predictor. The results show that the matched predictor is very nearly optimal but not exactly so, and that DPCM is fairly robust to mismatch of the prediction coefficient to the correlation coefficient of a first-order autoregressive source. >