Proceedings ArticleDOI
Baseband LPC coders for speech transmission over 9.6 kb/s noisy channels
R. Viswanathan,A. Higgins,W. Russell,John Makhoul +3 more
- Vol. 5, pp 348-351
TLDR
This paper presents the results of the investigation of the various aspects of baseband LPC coders with the goal of maximizing the speech quality at a transmission bit-rate of 9.6 kb/s and for channel bit-error rates of up to 1%.Abstract:
This paper presents the results of our investigation of the various aspects of baseband LPC coders with the goal of maximizing the speech quality at a transmission bit-rate of 96 kb/s and for channel bit-error rates of up to 1% Important among these aspects are: baseband width, coding of baseband, high-frequency regeneration, and error protection of important transmission parameters The paper discusses these and other issues, presents the results of speech-quality tests conducted during the various stages of optimization, and describes the details of the optimized speech coderread more
Citations
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Multicast routing of hierarchical data
TL;DR: In this article, the authors propose an alternative approach, in which the source encodes its signal hierarchically, and the network delivers subsets of the signal layers in accordance with individual destinations' bandwidth constraints.
Proceedings ArticleDOI
Mediumband speech processor with baseband residual spectrum encoding
G.S. Kang,L. Fransen,E. Kline +2 more
TL;DR: The Navy has developed a Multirate Processor (MRP), which generates digitized speech at 2.4, 9.6, and 16 kb/s by the linear predictive coding principle, and under various operational conditions, the Diagnostic Rhyme Test (DRT) scores of the MRP compare favorably to the DRT scores of an existing 16 kb /s rate Continuously Variable Slope Delta (CVSD) encoder.
Proceedings ArticleDOI
RELP-vocoding with uniform and non-uniform down-sampling
TL;DR: Non-uniform decimation is proposed as one candidate for improving the quality of RELP vocoders and preliminary listening tests indicate that the methods proposed do improve the subjective quality significantly.
Proceedings ArticleDOI
Noisy-channel performance of 16 kb/s APC coders
TL;DR: Most impressive of the several interesting and useful results reported in the paper is that the final optimized, robust coder design yields speech quality that degrades only slightly as the bit-error rate is increased from 0% to 1%.
Journal ArticleDOI
Real-Time Speech Coder Implementation on an Array Processor
TL;DR: This paper considers successful approaches to problems of real-time software design and debugging, system reliability, and implementation correctness in the context of two real- time speech coder algorithms implemented on an array processor, a linear predictive baseband coder, and an adaptive predictive coder operating at 16 kbits/s.
References
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Proceedings ArticleDOI
High-frequency regeneration in speech coding systems
John Makhoul,M. Berouti +1 more
TL;DR: It is shown that the degree of rectification does not affect the output speech, and that the high-frequency noise source may be eliminated with proper processing, and a new type of HFR based on spectral duplication of the baseband is introduced.
Proceedings ArticleDOI
Voice-excited LPC coders for 9.6 kbps speech transmission
TL;DR: This paper considers the use of voice-excited linear predictive (LPC) coders for speech transmission at a bit-rate of 9.6 kbps, and study in detail the various aspects of this class of speech coders, with the goal of maximizing the speech quality at the above rate.
Journal ArticleDOI
New high‐frequency regeneration (HFR) techniques for voice‐excited speech coders
TL;DR: Several modifications to the spectral folding method are investigated with the goal of reducing or masking the tonal noises at the cost of increased computations.
Journal ArticleDOI
Some effects of speech materials on vocoder quality evaluations
TL;DR: In this article, a set of six sentences were composed, of which the first contained only vowels and /r, w, y, besides vowels, the next three sentences contained only nasals, only fricatives, and only stops and affricates, respectively.