The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 22, 1989
Filed:
Apr. 20, 1988
Kenichiro Hosoda, Tokyo, JP;
Shinji Kawaguchi, Tokyo, JP;
Atsushi Shinbo, Tokyo, JP;
Kiyoshi Yokota, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
In an ADPCM encoding and decoding system comprising an encoder having an adaptive predictor and an adaptive quantizer and a decoder having an adaptive predictor and an inverse adaptive quantizer, the adaptive predictors each comprise: an adaptive-zero predictor of an arbitrary order and an adaptive-pole predictor of an arbitrary order, for input signals with time-varying frequency components; a fixed-pole predictor of an arbitrary order, for input signals the frequency composition of which remains substantially invariant over time; and an offset predictor for rejecting an offset component of the input signals, these elements being connected in series. The adaptive-zero and adaptive-pole predictors generate estimates for voice signals with time-varying frequency components. The fixed-pole predictor generates estimates for voiceband data signals the frequency components of which remain substantially invariant over time. The adaptive predictors effectively operate for voice and voiceband data signals, providing a higher prediction gain. The quantizer provides a stably higher signal-to-quantization noise ratio for modem signals.