What is adaptive equalization when it is used?
An adaptive equalizer is an equalizer that automatically adapts to time-varying properties of the communication channel. It is frequently used with coherent modulations such as phase-shift keying, mitigating the effects of multipath propagation and Doppler spreading.
What is the need for adaptive equalization for data transmission?
Adaptive equalization can be used to improve digital data transmission on wireless links with time-varying multipath distortion. This paper summarizes some of the performance aspects of adaptive equalization in wireless applications.
What is the advantage of adaptive equalizers?
Adaptive equalization removes linear errors from modulated signals by dynamically creating and applying a FIR (feed-forward) compensating filter. Linear errors can come from filters in a transmitter or receiver’s IF or from the presence of multiple paths in the transmission path, such as reflections in a cable system.
What does Equalization mean?
transitive verb. 1 : to make equal. 2a : to compensate for. b : to make uniform especially : to distribute evenly or uniformly equalize the tax burden. c : to adjust or correct the frequency characteristics of (an electronic signal) by restoring to their original level high frequencies that have been attenuated.
Which are the two operation modes for an adaptive equalizers?
Operating Modes of Adaptive Equalizer Adaptive equalizer can operate in two modes: Decision Directed Mode which indicates that the receiver decisions are used to generate error signal. Decision Directed Equalizer: This also indicates that adjustment is efficient in tracking slow variations in the channel response.
How is the signal at the adaptive equalizer represented?
(Note that in modern circuitry, the signal is often digitized before detection, and the detection, filtering, and equalization are performed using digital signal-processing techniques. The point is that the signal at the adaptive equalizer is a continuous signal, even if it is represented digitally.
Where does the adaptive equalizer go in DOCSIS?
In the past it has been most common to place the adaptive equalizer in the receiver, as is done in digital video receivers. However, DOCSIS modems have a unique need in the upstream direction that has caused the equalizer to be placed in the upstream transmitter (at the modem) and the detector in the Cable modem termination system (CMTS).
How is loss suppressed in a digital FIR equalizer?
•The loss in the channel is suppressed by boosting the high-frequency content of the signal. •Often results in larger noise margins. •Receivers can be implemented in discrete-time or continuous time. •Implementations include digital FIR equalizer, analog FIR equalizer, continuous time equalizer.
Which is fir for transfer function with zeros?
1 3 x [ n + 1]: The z -transform of the anticausal portion of the transfer function is z. This expression → ∞ as z → ∞, so it has a pole at z = ∞. This meets the criterion for an FIR response. This would imply that you gave a difference equation for a non-causal FIR filter. Transfer function with only zeros is FIR.