Susan Levit Webber

US Patent:

40484432, Sep 13, 1977

Filed:

Dec 12, 1975

Appl. No.:

5/640218

Inventors:

Ronald Eldon Crochiere - Chatham NJ
James Loton Flanagan - Warren NJ
Susan Anne Webber - North Plainfield NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

G10L 100

US Classification:

179 1SA

Abstract:

A digital speech communication arrangement includes apparatus for partitioning a speech signal into a plurality of nonuniformly related, preassigned intelligibility contributing subbands, and quantized with an accuracy (bit allocation) based upon perceptual criteria. As a result, the quality of the coded signal is improved over that obtained from a single full-band coding of the total spectrum. "Integer-band" sampling may be employed to alias the signal in an advantageous way before coding. Each subband portion is digitally encoded after sampling at a rate related to the bandwidth of the subband. The digital codes of the subband are combined and applied to a common communication channel. A replica of each subband is formed by separating the digital codes, producing a sampled form of each digital coded signal and selecting the subband of the speech signal from said sampled form. The subbands are combined to reconstruct the speech signal.