A new PCM transmission system is proposed. At present, near instantaneous companding is being considered as one of the PCM sound transmission methods for satellite broadcasts. Its quality performance and efficiency, h...
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A new PCM transmission system is proposed. At present, near instantaneous companding is being considered as one of the PCM sound transmission methods for satellite broadcasts. Its quality performance and efficiency, however, are not satisfactory in every respect. The system proposed combines differential PCM with a near instantaneous companding capability. By combining the advantages of both methods, a remarkable improvement is achieved in the lower frequency signal band and high transmission efficiency is realized at the same time.
This paper describes a coding scheme to transmit high resolution TV signals at a rate of 200 Mb/s by employing intraframe DPCM coding. First, statistical characteristics are measured. Then, coding parameters such as p...
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This paper describes a coding scheme to transmit high resolution TV signals at a rate of 200 Mb/s by employing intraframe DPCM coding. First, statistical characteristics are measured. Then, coding parameters such as predictive functions and quantizer characteristics, are studied by simulation. Coding performances are evaluated for the processed pictures in terms of S/N ratio, subjective evaluation and coding efficiency. Simulation results show that a two dimensional predictor using the previous sample and the samples on the previous line, with 29-level quantizer for Y signal and 7-level quantizer for CW, CN signals, gives the best performance. In addition, it is shown that another two dimmensional predictor which is feasible for hardware implementation, make it possible to transmit high resolution TV signals at a rate of 200 Mb/s.
作者：
Sayood, KhalidUniv of Nebraska
Dep of Electrical Engineering Lincoln NE USA Univ of Nebraska Dep of Electrical Engineering Lincoln NE USA
Quantization noise constitutes the limiting factor on DPCM performance. For a low number of levels in the quantizer, this noise is also correlated. A technique for improving the performance of the DPCM system at a ver...
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Quantization noise constitutes the limiting factor on DPCM performance. For a low number of levels in the quantizer, this noise is also correlated. A technique for improving the performance of the DPCM system at a very modest cost is presented. The technique involves the use of an adaptive transversal filter at the receiver output to reduce the effects of quantization noise. The filter is trained at the transmitter and periodic updates sent to the receiver.
The survey is presented of soviet works on the noise stability problem of discrete single-channel information transmission systems employing adaptive pulse-codemodulation.
The survey is presented of soviet works on the noise stability problem of discrete single-channel information transmission systems employing adaptive pulse-codemodulation.
For *** see ibid., vol.16, no.16, p.2871 (1983). The circular orbit method (COM) which has been proposed in parts I and II is extended to coupled oscillator systems. The authors also develop a new method (they call it...
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For *** see ibid., vol.16, no.16, p.2871 (1983). The circular orbit method (COM) which has been proposed in parts I and II is extended to coupled oscillator systems. The authors also develop a new method (they call it the phase correlation method (PCM)) which enables one to calculate a particular state manifold. They apply the COM and PCM to calculations of state energy in the Henon-Heiles and Barbanis potential systems and examine the efficiency of them.
In telecommunications systems, digital encoding and decoding using pulse code modulation (PCM) techniques can provide relative freedom from noise interference. Maintaining a PCM system, however, involves not only a ra...
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In telecommunications systems, digital encoding and decoding using pulse code modulation (PCM) techniques can provide relative freedom from noise interference. Maintaining a PCM system, however, involves not only a range of typical audio measurements but several tests exclusively used for this type of communication system. The most important measurements on a PCM system are described. They are: measurement of analog parameters between the inputs and outputs of audio frequency, measurement of the send side from the audio frequency input to the digital signal output and from the digital signal input to the audio frequency output, and measurements of the digital signal transmission equipment.
Results are presented of subjective tests conducted by organizations representing seven countries (China, France, West Germany (FRG), Italy, Japan, United Kingdom, United States), administered on site in the native la...
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Results are presented of subjective tests conducted by organizations representing seven countries (China, France, West Germany (FRG), Italy, Japan, United Kingdom, United States), administered on site in the native language and based on speech samples processed through a transistor-transistor logic hardware implementation of the algorithm under various network conditions. The network conditions included single and multiple encodings, mixed PCM, ADPCM configurations, and impairments such as circuit noise and digital line errors. For comparison, reference conditions such as PCM were also included. The results appear in terms of mean opinion scores obtained by subjects who listened to samples of processed speech from male and female speakers. In absolute terms, the performance spread between countries is quite large. However, the relative performance within each country compared with the reference conditions such as PCM was found to be consistent for all countries. The ADPCM algorithm performance between analog interfaces is equivalent to between three and four asynchronous encodings of PCM. Results also cover synchronous operation, the effect of network impairments, varying input levels, and linear and carbon microphone speech.
作者：
Sayood, KhalidUniv of Nebraska-Lincoln
Dep of Electrical Engineering Lincoln NE USA Univ of Nebraska-Lincoln Dep of Electrical Engineering Lincoln NE USA
Quantization noise constitutes the limiting factor on DPCM performance. For a small number of levels in the quantizer this noise is also correlated. A technique is presented for improving the performance of the DPCM s...
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Quantization noise constitutes the limiting factor on DPCM performance. For a small number of levels in the quantizer this noise is also correlated. A technique is presented for improving the performance of the DPCM system at a very modest cost.
作者：
Pearson, DonUniv of Essex
Dep of Electrical Engineering Science Colchester Engl Univ of Essex Dep of Electrical Engineering Science Colchester Engl
Data compression in DPCM differential pulse code modulation, is effected primarily through quantization of the predictive error signal. Secondary compression may be obtained through variable word-length coding of the ...
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Data compression in DPCM differential pulse code modulation, is effected primarily through quantization of the predictive error signal. Secondary compression may be obtained through variable word-length coding of the quantized signal. This paper concentrates on the design of the quantizer and explains how this changes with changes in the predictor. It was thought that relatively simple previous-element or previous-line predictors were adequate, but quite complicated predictors have been shown to be useful. Since it may be necessary to code not only the component studio signals but also the composite PAL signal at some point in the transmission path (as, for example, over an optical-fibre link inserted in an analogue path for some special purpose), the paper also considers how this affects quantizer design.
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