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Pulse-code modulation (PCM) is a method used to digitally represent analog signals.It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications.
A PCM signal is a sequence of digital audio samples containing the data providing the necessary information to reconstruct the original analog signal.Each sample represents the amplitude of the signal at a specific point in time, and the samples are uniformly spaced in time.
The audio bit rate for a Red Book audio CD is 1,411,200 bits per second (1,411 kbit/s) or 176,400 bytes per second; 2 channels × 44,100 samples per second per channel × 16 bits per sample. Audio data coming in from a CD is contained in sectors, each sector being 2,352 bytes, and with 75 sectors containing 1 second of audio.
Linear pulse-code modulation (LPCM, generally only described as PCM) is the format for uncompressed audio in media files and it is also the standard for CD-DA; note that in computers, LPCM is usually stored in container formats such as WAV, AIFF, or AU, or as raw audio format, although not technically necessary.
G.711 is a narrowband audio codec originally designed for use in telephony that provides toll-quality audio at 64 kbit/s. It is an ITU-T standard (Recommendation) for audio encoding, titled Pulse code modulation (PCM) of voice frequencies released for use in 1972.
Hardware audio codecs send and receive digital data using buses such as AC'97, SoundWire [5], I²S, SPI, I²C, etc. Most commonly the digital data is linear PCM , and this is the only format that most codecs support, but some legacy codecs support other formats such as G.711 for telephony.
The DVD-Audio format uses standard, linear PCM at variable sampling rates and bit depths, which at the very least match and usually greatly surpass those of standard CD audio (16 bits, 44.1 kHz). In the popular Hi-Fi press, it had been suggested that linear PCM "creates [a] stress reaction in people", and that DSD "is the only digital recording ...
In telecommunications and computing, bit rate (bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time. [1]The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). [2]