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pulse code modulation
Last modified: Tuesday, April 08, 2008
Short for pulse code modulation, a sampling technique for digitizing analog signals, especially audio signals. PCM samples the signal 8000 times a second; each sample is represented by 8 bits for a total of 64 Kbps. There are two standards for coding the sample level. The Mu-Law standard is used in North America and Japan while the A-Law standard is use in most other countries.
PCM is used with T-1 and T-3 carrier systems. These carrier systems combine the PCM signals from many lines and transmit them over a single cable or other medium.
PCM is also the usual digital method used for music audio playback of music CDs. While supported by DVDs, DVDs have a greater volume so they use Linear PCM, which has a higher sampling rate — up to 24-bit at a sampling rate of 96 kHz.
Bitstream versus PCM debate for high-density compact disc Implicit to the ARA proposal is the use of uniform sampling and uniform amplitude quantization with dither, where specifications up to 24 bit at a sampling rate of 96 kHz are supported, a process designated linear PCM. It is a fundamental premise of our proposal that there will be no form of lossy perceptual coding employed and that each channel of the system will be bit-transparent from input to output.
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