Accession Number:

AD0606271

Title:

WEIGHTED PCM,

Descriptive Note:

Corporate Author:

RAND CORP SANTA MONICA CALIF

Personal Author(s):

Report Date:

1957-10-28

Pagination or Media Count:

3.0

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

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE