ADC

A device in the form of a chipset that receives analog signals, measures the input at a regular sampling interval (or on command), and reports a digital output of the results. In a typical application, an ADC samples the analog signal at a fixed interval with enough resolution to accurately describe the analog waveform. In a typical voice application, for example, an ADC samples the audio stream 8,000 times per second at a precise interval of 125 microseconds ( 1 / 8,000 of a second) and reports a 14- or 16-bit value per sample. A digital signal processor (DSP) or other hardware then encodes the signal into pulse code modulation (PCM) format, employing an appropriate algorithm such as A-law or mu-law to produce a standard output like a DS-0 channel. At the receiving end of the connection, a matching DSP or other hardware and a digital-to-analog converter (DAC) reverses the process. See also A-law, algorithm, analog, channel, digital, DSP, DS-0, encode, mu-law, PCM, and signal.