WEIGHTED PCM,
Abstract
A modified form of pulse-code-modulation, called weighted PCM, is described wherein the relative amplitudes of the pulses within the pulse code groups are adjusted in such a fashion as to minimize the noise power in the reconstructed signal due to errors in transmission. A performance analysis shows the knee of the output signal to-noise ratio curve to be moved 1.4 db to the left for a weighted 7-digit PCM system while an information-rate study reveals that the maximum improvement over a conventional 7-digit PCM system, which can ever be achieved by any encoding process, is only 8 db. The importance of selecting a suitable system-worth criterion is emphasized by showing that weighting increases the information rate relative to an RMS-fidelity criterion but decreases it on a pure equivocation basis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 28, 1957
- Accession Number
- AD0606271
Entities
People
- Edward Bedrosian
Organizations
- RAND Corporation