Calculated Quantizing Noise of Single-Integration Delta-Modulation Coders

While Laane and Murphy 1 were investigating the encoding of speech using delta modulation (AM) 2 it became apparent to us that existing theories of granular quantizing noise3'4 were seriously deficient; they did not take into account, except in a very elementary way, the asymmetry of the positive and negative integrator step sizes. This work intends to correct this deficiency. Figure 1 is a block diagram of a AM coder-decoder. An input signal is compared with a locally reconstructed version of itself and the differential, or error, is quantized into a one-bit code, transmitted, and integrated at a receiver to recover the original signal. Quantizing noise is produced by the coding process and is also recovered at the 2359 2378 T H E BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER CLOCK lflfifl CODER- DECODER- SIGNAL OUT INTEGRATOR AM IN Fig. 1 -- Delta-modulation coder plus decoder (codec).