Modulation in which a signal is sampled, and the magnitude (with respect to a fixed reference) of each sample is quantized and digitized for transmission over a common transmission medium.
A modulation system in which the standard values of a quantized wave are indicated by a series of coded pulses.
A straightforward, uncompressed, coding method in which analog signals are sampled at regular intervals and each sample is represented by a digital number representing the amplitude at that instant in time. Sampling is done at a frequency at least 2 times the highest frequency of interest, and the digital number must have a sufficient number of bits to capture and reconstruct the essential qualities of the audio signal (dynamic range, low distortion and noise, etc.). E.G. normal CD's are recorded using a sampling frequency of 44.1 kHz using a 16 bit digital number. See: Bit, Compression.
A common method used in encoding, transmitting, and storing digital data.
A special digital encoding of a frequency modulated signal. FM is still utilized, however, the control information is in the form of a digital word rather than just a pulse width, as is used with standard AM or FM. Using PCM adds additional protection against interference from various sources.
a modulation technique. It is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals of duration T. Every sample is quantized to a series of symbols in a digital code, which is usually a binary code. Nyquist's theorem states that frequencies higher than half the sample frequency (fs = 1 / T) cannot be reconstructed.
(PCM): A technique in which an analog signal, such as a voice, is converted into a digital signal by sampling the signal's amplitude and expressing the different amplitudes as a binary number. The sampling rate must be at least twice the highest frequency in the signal.
Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code. PCM has been used in digital telephone systems and is also the standard form for digital audio in computers and the compact disc red book format. It is also standard in digital video, for example, using ITU-R BT.601.