Two very different subband coders are described. The first is a modified dynamic bit-allocation-subband coder (D-SBC) designed for variable rate coding situations and easily adaptable to noisy channel environments. It can operate at rates as low as 12 kb/s and still give good quality speech. The second coder is a 16-kb/s waveform coder, based on a combination of subband coding and vector quantization (VQ-SBC). The key feature of this coder is its short coding delay, which makes it suitable for real-time communication networks. The speech quality of both coders has been enhanced by adaptive postfiltering. The coders have been implemented on a single AT&T DSP32 signal processor


Electrical and Computer Engineering

Keywords and Phrases

AT&T; DSP32 Signal Processor; Adaptive Postfiltering; Coding Delay; Digital Filters; Encoding; Filtering and Prediction Theory; Modified Dynamic Bit-Allocation-Subband Coder; Noise; Noisy Channel Environments; Real-Time Communication Networks; Speech Analysis and Processing; Speech Quality; Subband Coding; Vector Quantization; Vocoders; Voice Equipment; Waveform Coder

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 1988 Institute of Electrical and Electronics Engineers (IEEE), Institute of Industrial Engineers (IIE), All rights reserved.

Publication Date

01 Jan 1988