About Equalization (802.11b/g DSSS/CCK/PBCC)

Equalization removes linear errors from modulated signals by dynamically creating and applying a FIR Finite Impulse Response 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. These types of problems appear as group-delay distortion, frequency-response errors (tilt, ripple), and reflections or multipath distortion.

Equalization enables measurement of some impaired channels and can be used to isolate linear from non-linear error mechanisms.

Important Concepts

The following paragraphs highlight important concepts about Equalization:

The primary application of the equalizer's impulse-response display is for evaluating multi-path environments. Multi-path environments usually require longer filter lengths.
The primary application of the equalizer's frequency-response display is for evaluating the transmitter or receiver signal-path for errors such as passband ripple and group-delay distortion. Short filter lengths usually work well for these types of measurements.
The VSA estimates new filter coefficients with each measurement.