Home > Terms > English (EN) > signal compression

signal compression

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. Note 1: Signal compression is usually expressed in dB. Note 2: Instantaneous values of the input signal that are low, relative to the reference level, are increased, and those that are high are decreased. Note 3: 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. Note 4: 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. Note 5: Signal compression always introduces distortion, which is usually not objectionable, if the compression is limited to a few dB. Note 6: The original dynamic range of a compressed signal may be restored by a circuit called an "expander. " 2. In facsimile systems, a process in which the number of pels scanned on the original is larger than the number of encoded bits of picture information transmitted.

0
Collect to Blossary

Member comments

You have to log in to post to discussions.

Terms in the News

Billy Morgan

Sports; Snowboarding

The British snowboarder Billy Morgan has landed the sport’s first ever 1800 quadruple cork. The rider, who represented Great Britain in the 2014 Winter Olympics in Sochi, was in Livigno, Italy, when he achieved the man-oeuvre. It involves flipping four times, while body also spins with five complete rotations on a sideways or downward-facing axis. The trick ...

Marzieh Afkham

Broadcasting & receiving; News

Marzieh Afkham, who is the country’s first foreign ministry spokeswoman, will head a mission in east Asia, the state news agency reported. It is not clear to which country she will be posted as her appointment has yet to be announced officially. Afkham will only be the second female ambassador Iran has had. Under the last shah’s rule, Mehrangiz Dolatshahi, a ...

Weekly Packet

Language; Online services; Slang; Internet

Weekly Packet or "Paquete Semanal" as it is known in Cuba is a term used by Cubans to describe the information that is gathered from the internet outside of Cuba and saved onto hard drives to be transported into Cuba itself. Weekly Packets are then sold to Cuban's without internet access, allowing them to obtain information just days - and sometimes hours - after it ...

Asian Infrastructure Investment Bank (AIIB)

Banking; Investment banking

The Asian Infrastructure Investment Bank (AIIB) is an international financial institution established to address the need in Asia for infrastructure development. According to the Asian Development Bank, Asia needs $800 billion each year for roads, ports, power plants or other infrastructure projects before 2020. Originally proposed by China in 2013, a signing ...

Spartan

Online services; Internet

Spartan is the codename given to the new Microsoft Windows 10 browser that will replace Microsoft Windows Internet Explorer. The new browser will be built from the ground up and disregard any code from the IE platform. It has a new rendering engine that is built to be compatible with how the web is written today. The name Spartan is named after the ...

Featured Terms

tula.ndex
  • 0

    Terms

  • 51

    Blossaries

  • 11

    Followers

Industry/Domain: Physics Category: Color science

invisibility block

Scientists in Singapore have discovered a way to make objects disappear from view by bending light around them. The technology has potential for use ...