32 kb/s Adaptive Differential pulsecoded modulation (ADPCM) is a widely accepted high quality speech coding algorithm. Single chip devices exist for 32 kb/s ADPCM. This algorithm requires a relatively large bandwidth...
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32 kb/s Adaptive Differential pulsecoded modulation (ADPCM) is a widely accepted high quality speech coding algorithm. Single chip devices exist for 32 kb/s ADPCM. This algorithm requires a relatively large bandwidth and does not perform exceptionally well in noisy wireless environments. The 16 kb/s low-delay code excited linear prediction (LD-CELP) coding algorithm does perform well in noisy environments and requires a reduced bandwidth. Through algorithm optimization and simulated verification of mixed analog and digital VLSI partitioning a single chip implementing the 16 kb/s LD-CELP voice coding algorithm will be possible. The performance of this coder chip will be comparable to the quality of 32 kb/s ADPCM. In this paper we propose the use of a link between Comdisco's SPW and Synopsis to determine the hardware related performance degradation and the technology/complexity related power dissipation and area parameters. It will both prove the concept of design and determine the VLSI implementation feasibility.
Theoretical analysis of matched DPCM of a first order Gauss-Markov process was carried out for DPCM system with a uniform quantizer, an entropy constrained optimal uniform-threshold quantizer, and an adaptive stepsize...
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Theoretical analysis of matched DPCM of a first order Gauss-Markov process was carried out for DPCM system with a uniform quantizer, an entropy constrained optimal uniform-threshold quantizer, and an adaptive stepsize uniform quantizer. The work presented here is concerned with the design and analysis of a DPCM system with a Lloyd-Max quantizer and a DPCM system with a switched quantizer.
The traditional DSP design and development environment is generally based on the use of a single processor and suffers from a number of limitations including the following: a time-consuming design cycle from specifica...
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The traditional DSP design and development environment is generally based on the use of a single processor and suffers from a number of limitations including the following: a time-consuming design cycle from specification to the final product development; dependence on hardware and hence lack of portability to different DSP platforms; lack of exploitation of algorithmic and architectural parallelism for DSP design. The authors present a multiprocessor environment, called Taurus, for design and development of DSP algorithms and applications. The important features of such environment are introduced, and typical experimental results using an ADPCM system are presented and discussed.< >
Research at the author's university has identified that communication between users of workstations in an environment would be considerably enhanced if a real-time speech link was available in addition to 'scr...
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Research at the author's university has identified that communication between users of workstations in an environment would be considerably enhanced if a real-time speech link was available in addition to 'screen-share' facilities. This paper investigates the problems of implementing a real-time interactive speech link by integrating the speech packets (PCM) within the data frames employed on commercially available LANs. This is a step towards remote tutoring in higher education.< >
Prediction is one of the main processes in differential pulse-codemodulation (DPCM). The method of prediction in the differential coding of television pictures affects the degree of reduction of redundancy achievable...
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Prediction is one of the main processes in differential pulse-codemodulation (DPCM). The method of prediction in the differential coding of television pictures affects the degree of reduction of redundancy achievable and in particular the noise immunity of picture transmission systems. The median prediction algorithms proposed in this paper enable the noticeability of the transmission errors on the received picture to be reduced considerably.
The history of the development of Chinese telemetry is introduced in the paper. The new telemetry ground station and the new onboard space telemetry system, with the idea of systematic design and the specification, ar...
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The history of the development of Chinese telemetry is introduced in the paper. The new telemetry ground station and the new onboard space telemetry system, with the idea of systematic design and the specification, are described.
In this paper we discuss and compare advances in bandwidth efficient coding and signalling techniques, especially trellis-coded modulation (TCM). We consider power efficient TCM schemes, such as Ungerbock TCM, correla...
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ISBN:
(纸本)0780309170
In this paper we discuss and compare advances in bandwidth efficient coding and signalling techniques, especially trellis-coded modulation (TCM). We consider power efficient TCM schemes, such as Ungerbock TCM, correlative trellis-coded modulation (C-TCM), which is optimized with respect to bandwidth efficiency, and coded overlapped quadrature modulation, which uses overlapping pulses. The bandwidth/power tradeoff of these schemes is presented, thereby illuminating the different design philosophies.
The hardware and algorithms used to vector quantize predicted pixel intensity differences for real-time video compression are described. The hardware is designed for rapid vector quantization (VQ) performance, which e...
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The hardware and algorithms used to vector quantize predicted pixel intensity differences for real-time video compression are described. The hardware is designed for rapid vector quantization (VQ) performance, which entails the development of application-specific associative memory circuits. A modified DPCM algorithm is originally examined to determine how neural circuitry could enhance its operation. It was determined that quantization and encoding could be improved by consolidating these two functions into one, and by increasing the amount of information (i.e. number of pixels) quantized at a time. The result is a predictive scheme that vector quantizes differential values. Some of the disadvantages of VQ algorithms are solved using associative memories. The video compression algorithm and the associative memory design are described.< >
PCM codecs have stringent gain and signal-to-total distortion test requirements. Test cost is substantial due to long (s 10 s) real-time stimulation period and high cost of test equipment. A new test method is describ...
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pulse to pulse staggering in the pulse reference interval (PRI), usually used to increase the radar unambiguous range and MTI blind speeds, complicates notably the synchronization of the pulsed waveform. A free runnin...
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pulse to pulse staggering in the pulse reference interval (PRI), usually used to increase the radar unambiguous range and MTI blind speeds, complicates notably the synchronization of the pulsed waveform. A free running open loop technique may be used for this purpose, adjusting a stable clock at the same frequency as the transmitted pulses, which is synchronized by the received sequence during direct illumination. When the received signal can be contaminated by interferences, noise, or multipath effects, a more robust closed loop approach is desirable. This paper presents a closed loop solution to the synchronism process, based on a delay-lock loop configuration, using the special properties of the pulse to pulse staggered signal, that can be considered as a digital pseudorandom codemodulation with a period equal to the PRI.< >
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