An adaptive equalizer is an equalizer that automatically adapts to time-varying properties of the communication channel.[1] It is frequently used with coherent modulations such as phase-shift keying, mitigating the effects of multipath propagation and Doppler spreading.
Adaptive equalizers are a subclass of adaptive filters. The central idea is altering the filter's coefficients to optimize a filter characteristic. For example, in case of linear discrete-time filters, the following equation can be used:[2]
where is the vector of the filter's coefficients, is the received signal covariance matrix and is the cross-correlation vector between the tap-input vector and the desired response. In practice, the last quantities are not known and, if necessary, must be estimated during the equalization procedure either explicitly or implicitly.
Many adaptation strategies exist. They include, e.g.:
Least mean squares filter (LMS) Note that the receiver does not have access to the transmitted signal when it is not in training mode. If the probability that the equalizer makes a mistake is sufficiently small, the symbol decisions made by the equalizer may be substituted for .[3]
Stochastic gradient descent (SG)
Recursive least squares filter (RLS)
A well-known example is the decision feedback equalizer,[4][5] a filter that uses feedback of detected symbols in addition to conventional equalization of future symbols.[6] Some systems use predefined training sequences to provide reference points for the adaptation process.
An adaptiveequalizer is an equalizer that automatically adapts to time-varying properties of the communication channel. It is frequently used with coherent...
regions of an image. A variant of adaptive histogram equalization called contrast limited adaptive histogram equalization (CLAHE) prevents this by limiting...
rebooted twice with a trilogy of movies (The Equalizer in 2014, The Equalizer 2 in 2018, and The Equalizer 3 in 2023) starring Denzel Washington and a...
at all. Often the channel response is not known beforehand, and an adaptiveequalizer is used to compensate the frequency response. One way to study ISI...
ADSL—Asymmetric Digital Subscriber Line ADT—Abstract Data Type AE—AdaptiveEqualizer AES—Advanced Encryption Standard AF—Anisotropic Filtering AFP—Apple...
straightforward technique adaptive to the input image and an invertible operator. So in theory, if the histogram equalization function is known, then the...
GSM, the known sequence acts as a training pattern to initialize an adaptiveequalizer. The IS-54 system has different synchronization sequences for each...
ISBN 0-8352-2667-0. Review by Nathan Shumate at Cold Fusion Video Equalizer 2000 at IMDb Equalizer 2000 at Rotten Tomatoes Equalizer 2000 at AllMovie v t e v t e v t e...
transmission system with asynchronous receivers patent Communications system Adaptiveequalizer Meurant, Gerard (2006). The Lanczos and Conjugate Gradient Algorithms:...
I/O mezzanine modules Supporting up to 10 Gbit/s transmission with adaptivelyequalized I/O Supporting single ended and differential signaling up to 2 Gbit/s...
(ISI)) unknown memory (Viterbi decoders) possibly infinite memory (adaptiveequalizers) In principle, the importance sampling ideas remain the same in these...
transmission in both directions through the use of echo cancellation with adaptiveequalization called hybrid circuits (this is like telephone hybrid) and five-level...
Lucky pur / Purdue University Electrical engineer who invented the adaptiveequalizer Ellison Onizuka colo / University of Colorado Boulder NASA astronaut...
of UAC to vertical channels. Adaptiveequalization methods have been tried with limited success. Adaptiveequalization tries to model the highly reflective...
ML-drives used sophisticated power-optimization during writing and adaptiveequalization during reading. MultiLevel recording is sometimes confused with...
reprised his role in his first sequel, The Equalizer 2 (2018) and the third and final sequel The Equalizer 3 (2023). In 2016, Washington starred in The...
performance "powerful". Sanders co-starred in The Equalizer 2, a sequel to the hit action film The Equalizer, opposite Denzel Washington. In 2019, Sanders...
Ford in the drama series The First Lady (2022), and a CIA agent in The Equalizer 3 (2023). In 2024, she starred in the thriller series Ripley (2024). Fanning...
role of Robert McCall in The Equalizer. At the Emmy Awards from 1986 to 1990, he was nominated each year for The Equalizer. Golden Globe Award for Best...