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GROUP DELAY EQUALIZERS
When specifying filters the most common parameters are related to Insertion
Loss, Amplitude Response, and Return Loss. However, frequently constraints are
specified for maximum allowable Group Delay in the pass band to minimize
distortion of the transmitted/received signal.
Group Delay limits can be specified as maximum allowable Parabolic Group Delay
at the band edges. Also Maximum allowable Slope Group Delay over the pass band
as well as maximum allowable Ripple Group Delay over the pass band can be
specified. When Group Delay is specified it is usually understood to be in terms
of Relative Group Delay.
DNP can design and build networks to equalize the Group Delay of the filter to
allowable limits. Ideally the Group Delay characteristics of these networks
should be equal but opposite to the filter Group Delay. Quite often they are
also used to equalize system Group Delay as well as filter Goup Delay ( This has
the effect of minimizing distortion of the transmitted/received signal).
These networks are low loss and have a second order effect of somewhat
flattening pass band amplitude response.
Amplitude equalization can easily be incorporated into the same unit as Group
Delay Equalizers.
DNP builds conventional connectorized as well as SMT Group Delay Equalizers.
A measured (relative) group delay response of a Group Delay Equalizer over the range
of 100 MHz to 180 MHz is shown below. Notice the limit lines (red dashes) which
stipulate the allowable tolerance.
DNP can design GROUP DELAY EQUALIZERS from customer supplied curves or readings.
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