When PCM systems transmit harmonic signals they produce, at the same time, distortions (often called quantizing noise). These distortions excite both a nonlinear dependence of the output and input signal as well as ha...
详细信息
When PCM systems transmit harmonic signals they produce, at the same time, distortions (often called quantizing noise). These distortions excite both a nonlinear dependence of the output and input signal as well as harmonic signals appearing as ″stroboscopic″ components.
A new strategy for frame synchronization of PCM multiplex systems which use pulse stuffing (justification) is proposed. In devising this technique compatibility with existing CCITT systems was taken into consideration...
详细信息
A new strategy for frame synchronization of PCM multiplex systems which use pulse stuffing (justification) is proposed. In devising this technique compatibility with existing CCITT systems was taken into consideration. A comparison between the proposed strategy and the CCITT recommended system was made in terms of average holding time, average time for detection of synchronization loss and average synchronization recovery time. The proposed strategy proved to be significantly better in total synchronization time without sacrificing holding time capability.
The performance of PCM voice codeCS is studied by means of a statistical model for the digital errors in the Decoder-oder loop. With this model, the authors were able to devise a strategy for supervision of codeCs in ...
详细信息
The performance of PCM voice codeCS is studied by means of a statistical model for the digital errors in the Decoder-oder loop. With this model, the authors were able to devise a strategy for supervision of codeCs in PCM multiplex systems.
Photoconductivity (PC), photovoltaic and photoelectromagnetic (PEM) measurements are a very useful method for transport parameter investigation, particularly when the high resistivity of the materials makes difficult ...
详细信息
Photoconductivity (PC), photovoltaic and photoelectromagnetic (PEM) measurements are a very useful method for transport parameter investigation, particularly when the high resistivity of the materials makes difficult direct measurements. We have applied these effects to determine some transport parameters (τ,L) of the layered compounds GaSe, PbI2, HgI2at room temperature. The experimental results have been compared with different theoretical models of phototransport suggested for anisotropic compounds
Presentation of a three-dimensional non-linear prediction technique for use in differential pulse code modulation systems used to encode television signals. The prediction is a weighted sum of three estimates called r...
详细信息
Presentation of a three-dimensional non-linear prediction technique for use in differential pulse code modulation systems used to encode television signals. The prediction is a weighted sum of three estimates called representatives. Each representative is a non-linear estimate based on previous pels in one of three planes containing the pel to be predicted. The predictor is relatively insensitive to image statistics. Errors in the predictor input decay out with time.
This paper points out that the use of a planar prediction can improve the coding performance of the direct predictive coding systems for the NTSC color TV signal. Quantitative evaluation was made using the coding labo...
详细信息
This paper points out that the use of a planar prediction can improve the coding performance of the direct predictive coding systems for the NTSC color TV signal. Quantitative evaluation was made using the coding laboratory equipment designed for 32 Mbits/sec transmission. Analysis of the frequency response of the system shows that the planar prediction is well matched to the spectrum of the NTSC signal. The signal-to-noise ratio is approximately 42 DB with planar-predicted 4-bit-differential PCM (DPCM). In the case of ordinary broadcast programs, one can hardly tell the difference in picture quality between 4-bit DPCM and 8-bit PCM.
Presentation of a three-dimensional non-linear prediction technique for use in differential pulse code modulation systems used to encode television signals. The prediction is a weighted sum of three estimates called r...
详细信息
Presentation of a three-dimensional non-linear prediction technique for use in differential pulse code modulation systems used to encode television signals. The prediction is a weighted sum of three estimates called representatives. Each representative is a non-linear estimate based on previous pels in one of three planes containing the pel to be predicted. The predictor is relatively insensitive to image statistics. Errors in the predictor input decay out with time.
The IKM-30 pulse-codemodulation system is now being installed in urban telephone networks in order to provide large batches of connecting lines. The properties of signals which govern the interaction between automati...
详细信息
The IKM-30 pulse-codemodulation system is now being installed in urban telephone networks in order to provide large batches of connecting lines. The properties of signals which govern the interaction between automatic telephone exchanges and FM transmission systems, the advantages of a two-channel signaling system, and the matching devices (MD) of the PCM equipment are discussed. The technical capabilities of the MD of the IKM-30 equipment are also considered.
A new scheme for PCM encoding is introduced. Analog to digital conversion is made by per channel delta modulators, and most of the low-pass filtering is done by time shared digital filters. The main benefits of the sy...
详细信息
A new scheme for PCM encoding is introduced. Analog to digital conversion is made by per channel delta modulators, and most of the low-pass filtering is done by time shared digital filters. The main benefits of the system are the absence of crosstalk and low filtering costs.
A sequence of sample values of a band-limited input time function can be converted to the corresponding analog signal by appropriate filter and equalizing circuits. Based on an ideal reconstruction model and possible ...
详细信息
A sequence of sample values of a band-limited input time function can be converted to the corresponding analog signal by appropriate filter and equalizing circuits. Based on an ideal reconstruction model and possible scanning spectral, alternatives of signal conversion and practical realization for a PCM system are shown.
暂无评论