This article sets out the fundamental principles of pulse code modulation (P. C. M. ): the sampling and quantizing procedures which enable the analog to digital conversion and multiplexing.
This article sets out the fundamental principles of pulse code modulation (P. C. M. ): the sampling and quantizing procedures which enable the analog to digital conversion and multiplexing.
The paper deals with an investigation that was carried out to determine whether simple data-compression techniques could be applied successfully to an experimental 9.6 kbit/s adaptive p.c.m. digital speech system: The...
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The paper deals with an investigation that was carried out to determine whether simple data-compression techniques could be applied successfully to an experimental 9.6 kbit/s adaptive p.c.m. digital speech system: The main aim of the investigation was to ascertain whether compression factors of two or four could be achieved. In the paper, the results of the investigation are presented and it is shown that the adaptive p.c.m. system is converting speech into a 9.6 kbit/s digital form that appears to possess very little redundancy. The results of a statistical analysis of the data are given, and it is shown that a compression factor of two is unlikely to result in a speech quality that is commercially acceptable. The results of an experimental investigation that was carried out in support of the theoretical investigation are presented. The results of the experimental investigation show that although compression by a factor of two results in a speech quality that is commercially unacceptable, a 4/3 compression can be achieved without any serious degradation of the speech quality.
Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Plant and certain animal embryos appear to be responsive to the gravity vector during early stages of ...
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Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Plant and certain animal embryos appear to be responsive to the gravity vector during early stages of development. The convection of particl
Two differential PCM schemes are analyzed and compared with PCM. In D PCM the quantization is performed after the prediction, while the quantization is included in the prediction process in the case of DPCM. For both ...
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Two differential PCM schemes are analyzed and compared with PCM. In D PCM the quantization is performed after the prediction, while the quantization is included in the prediction process in the case of DPCM. For both coding schemes a gain formula is given. The formula is good both for arbitrary probability density functions and an arbitrary setting of the predictor coefficients. It is shown that DPCM schemes do not have a gain as compared to the PCM scheme if gaussian signals are quantized. Additionally the influence of channel errors is given for both differential PCM schemes. It is shown that, at least for gaussian signals, the effect of channel errors on the overall error is not greater than that in PCM.
Special features of quantization-noise measurement in pulse-codemodulation systems are discussed. A block diagram of a digital measuring instrument with automatic balancing of the measured quantity is given, and the ...
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Special features of quantization-noise measurement in pulse-codemodulation systems are discussed. A block diagram of a digital measuring instrument with automatic balancing of the measured quantity is given, and the special features of the construction of some of the units are discussed.
A PCM path with simplified generators is considered. These generators regenerate digitally the received pulses only in their form, but not in their phase position. The accumulation of the systematic intersymbol interf...
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A PCM path with simplified generators is considered. These generators regenerate digitally the received pulses only in their form, but not in their phase position. The accumulation of the systematic intersymbol interference disturbances over such simplified regenerators is described. The accumulation mechanism is demonstrated on typical models and for a real shape of receiving pulses.
A method for designing the parameters which determine the frame structure of asynchronous higher-order PCM systems is described. An optimum number of pulse positions reserved for the transmission of frame alignment an...
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A method for designing the parameters which determine the frame structure of asynchronous higher-order PCM systems is described. An optimum number of pulse positions reserved for the transmission of frame alignment and stuffing control signals has been ascertained with regard to reducing the reframe time of a chain of systems of the m-th to first order to a minimum. The selection of the specified stuffing rate has been based on the requirement that noise caused by the jitter due to pulse stuffing and the digital line is rejected as completely as possible.
The use of pulse code modulation (PCM) in the junction and trunk areas of telephone and data transmission is discussed. The principal parameters of the basic junction system upon which international standardization is...
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The use of pulse code modulation (PCM) in the junction and trunk areas of telephone and data transmission is discussed. The principal parameters of the basic junction system upon which international standardization is now proceeding are reviewed. In addition, the error noise performance of the system is examined, and it is shown how this differs markedly from Frequency Division Multiplex systems.
A prototype of a DPCM vocal transmission system with the quantizing step adapted to the short time prediction error power is described. The bit rate is of 32 kbit/s and the subjective quality is comparable with the on...
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A prototype of a DPCM vocal transmission system with the quantizing step adapted to the short time prediction error power is described. The bit rate is of 32 kbit/s and the subjective quality is comparable with the one of a standard logarithmic 8 bit PCM system. This prototype can be inserted in existing digital networks, where the PCM samples are available; the system can also be employed in multiplexing systems. The project has been implemented for the present prototype on the grounds of the combinatory and parallel logic.
A prototype of a DPCM vocal transmission system with the quantizing step adapted to the short time prediction error power is described. The bit rate is of 32 kbit/s and the subjective quality is comparable with the on...
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A prototype of a DPCM vocal transmission system with the quantizing step adapted to the short time prediction error power is described. The bit rate is of 32 kbit/s and the subjective quality is comparable with the one of a standard logarithmic 8 bit PCM system. This prototype can be inserted in existing digital networks, where the PCM samples are available;the system can also be employed in multiplexing systems. The project has been implemented for the present prototype on the grounds of the combinatory and parallel logic.
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