This paper presents a scalable three bit-rates (8, 14.1 and 24 il kbit/s) coder: For the two embedded lowest ones, operating in the telephone bandwidth, CELP coding techniques are used. For the highest rate, that both...
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This paper presents a scalable three bit-rates (8, 14.1 and 24 il kbit/s) coder: For the two embedded lowest ones, operating in the telephone bandwidth, CELP coding techniques are used. For the highest rate, that both improves narrowband quality and extends the band to [50-7000Hz], transform coding techniques are used. The main applications deal with transmission over network,with no guaranteed QoS.
The letter describes a method of improving the dynamic range of a continuously variable slope delta modulator (CVSD). This is achieved by modifying the basic step size ??0 Compared to the CVSD algorithm, the modified ...
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The letter describes a method of improving the dynamic range of a continuously variable slope delta modulator (CVSD). This is achieved by modifying the basic step size ??0 Compared to the CVSD algorithm, the modified CVSD (MCVSD) algorithm yields about 15??20 dB dynamic range improvement without degrading the peak SNR and the bit error rate tolerance.
The MPEG-2 Advanced Audio coder is the latest issue of the MPEG audio encoders/decoders family whose most popular version is known as MP3. It gathers many of the latest highly efficient sound compression techniques in...
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The MPEG-2 Advanced Audio coder is the latest issue of the MPEG audio encoders/decoders family whose most popular version is known as MP3. It gathers many of the latest highly efficient sound compression techniques in a quite classically structured coder. The main part is based or a Discrete Cosine Transform with variable resolution. The output from this filterbank is compressed by the combination of an adaptive bit allocation module, according to frequency subbands, and a set of noiseless Huffman codebooks. Bit allocation is controlled by a psychoacoustic model which determines an audibility threshold far signal distortion in the frequency domain. This article intends to explain the ISO standard without replacing it, and also to be a general introduction to perceptual audio coding.
A low delay coder for speech and music signals sampled at 32 kHz is described. Its algorithmic delay does not exceed 25 ms which enables audio conferencing applications without echo cancellation. Its bot rate is scala...
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A low delay coder for speech and music signals sampled at 32 kHz is described. Its algorithmic delay does not exceed 25 ms which enables audio conferencing applications without echo cancellation. Its bot rate is scalable between 64 and 32 kbits/s by steps of 8 kbits/s. The transmitter issues the binary code at 64 kbits/s with lower bit rate codes embedded in it. The receiver may operate at lower bit rates with gradual loss of quality. The proposed coder is based on a mixed scheme: the adopted solution contains elements from the CELP speech coder and frequency domain where bit allocation is calculated and transform coefficients are quantized. A first solution based on the DFT is discussed, then a second solution based on a MDCT with small overlap is applied. The quantization of these coefficients is done in the following way. First, a prediction of the whole spectrum is applied. Then, a mean-removed gain-shape split VQ is used for amplitude spectrum quantization and a hierarchical 2-dimensional VQ is used for phase spectrum quantization stage, each codeword describing the selected vector index is split into parts corresponding to different bit rates. Due to the hierarchical codebook structure, truncated indices may be used, without much affecting the signal quality. Simulation results are presented and the robustness of the proposed coder is examined.
The push button telephone has been employed in many systems as a computer terminal with a very restricted capability and in at least one instance as a com- puter terminal for a general purpose programming language Thi...
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The push button telephone has been employed in many systems as a computer terminal with a very restricted capability and in at least one instance as a com- puter terminal for a general purpose programming language This thesis discusses the input, output, coding, and decoding problems when considering a general purpose programming language for use with a push button telephone,, Included is a general discussion of a system that would use a syntactic analysis and the context of a programming language to produce a code for use with a push button telephone. The output from this analysis would be used to build a table-driven translator to decode the language An example of such a system is also included.
NASA Technical Reports Server (Ntrs) 20080009468: Serial Turbo Trellis Coded Modulation Using a Serially Concatenated coder by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20080009468: Serial Turbo Trellis Coded Modulation Using a Serially Concatenated coder by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20080008731: Vector Adaptive Predictive coder for Speech and Audio by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20080008731: Vector Adaptive Predictive coder for Speech and Audio by NASA Technical Reports Server (Ntrs); published by
[Auto Generated] CHAPTER CHAPTER CHAPTER CHAPTER INTRODUCTION 1.1 Speech Digitize tiai 1.2 Low bit-rate Generation 1.3 Sub-band Coding 1.4 Organisation of the Thesis SUB-BAND coder-SYSTEM DESCRIPTION 2.1 Sub-band Coding 2.2 Advantages of Sub-band Coding SELECTION OF SUB-BANDS AND INTBaER BmD SAMPLING 3.1 Criteria for Selecting Sub-bands 3.2 Integer Band Sampling 3.3 Choice of Sub-bands for Various Sampling Rates 3.4 Design and Implementation of the Filters DECIMATION AND INTERPOLATION 4.1 Sampli
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