A noise-reduction technique involving compression applied at the transmitter, with complementary expansion at the receiver. A form of noise reduction using compression at the transmitting end and expansion at the receiver. A compressor is an amplifier that increases its gain for lower power signals. The effect is to boost these components into a form having a smaller dynamic range. A compressed signal has a higher average level, and therefore, less apparent loudness than an uncompressed signal, even though the peaks are no higher in level. An expander reverse the effect of the compressor to restore the original signal.
It is a process where the dynamic range of a signal is compressed for recording purposes and next it is expanded to its original value for reproduction or playback.
Compressing and expanding. A device (or pair of devices) that compress a signal and then expands the signal to keep it within a set range and/or to reduce noise. Used in wireless microphone systems to take the whole audio signal and compress it into a frequency bandwidth that can be transmitted. The receiver expands the signal back into its original frequency range.
A logarithmic scheme for sampling analog signals that increases the resolution of signals with a low amplitude. Common standards include A-Law and u-Law.
A type of signal processing in which the signal is compressed on input and expanded back to its original form on output. Digital companding allows a device to achieve a greater apparent dynamic range with fewer bits per sample word.
Many analogue signals are not best digitised using uniform quantisation steps. For example, in speech small signal amplitudes are more common that large ones. For these signals the quantisation noise can be reduced by using smaller steps for lower amplitudes and larger steps for higher amplitudes. In effect, this compresses the signal range before transmission and expands it at the receiver. This compressing and expanding results in the term companding.
A noise-reduction technique that applies single compression at the transmitter and complementary expansion at the receiver.
Contraction derived from the opposite processes of compression and expansion. Part of the PCM process whereby analog signal values are logically rounded to discrete scale-step values on a nonlinear scale. The decimal step number is then coded in its binary equivalent prior to transmission. The process is reversed at the receiving terminal using the same nonlinear scale. Compare with compression and expansion. See also a-law and mu-law.
In telecommunication, signal processing, and thermodynamics, companding (occasionally called compansion) is a method of reducing the effects of a channel with limited dynamic range. The name is a portmanteau of compressing and expanding.
