Signal compression

related topics
{system, computer, user}
{math, number, function}
{rate, high, increase}

In telecommunication, the term signal compression has the following meanings:

In analog (usually audio) systems, reduction of the dynamic range of a signal by controlling it as a function of the inverse relationship of its instantaneous value relative to a specified reference level.

Signal compression is usually expressed in dB.

Instantaneous values of the input signal that are low, relative to the reference level, are increased, and those that are high are decreased.

Signal compression is usually accomplished by separate devices called "compressors." It is used for many purposes, such as (a) improving signal-to-noise ratios prior to digitizing an analog signal for transmission over a digital carrier system, (b) preventing overload of succeeding elements of a system, or (c) matching the dynamic ranges of two devices.

Signal compression (in dB) may be a linear or nonlinear function of the signal level across the frequency band of interest and may be essentially instantaneous or have fixed or variable delay times.

Signal compression always introduces distortion, which is usually not objectionable, if the compression is limited to a few dB.

The original dynamic range of a compressed signal may be restored by a circuit called an "expander".

 This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).

See also

Further reading

Definition: signal compression

Signal Compression

Signal Compression Lab UCSB

Signal Compression and Classification Group - Stanford

Full article ▸

related documents
Proxy ARP
Automated business process
Serial Line Internet Protocol
Uploading and downloading
Back Orifice
Horizontal blank interrupt
Call collision
Network architecture
Frequency frogging
NSAP address
Jam signal
Netscape Communicator
Internet backbone
National Information Infrastructure
Raster image processor
MD Data
Hierarchical routing
Automated information systems security
Category 3 cable
Communications in Germany