AnsweredAssumed Answered

Will adding zeroes to FIR filter coefficients to increase taps degrade  performance?

Question asked by kaushal Employee on Jan 21, 2009
Latest reply on Mar 19, 2010 by MikeSmithCanada

We have two FIR Filters, running on same input data, generated for  different
purposes.

1. FIR1 - N  Taps (as generated in Matlab)
2. FIR2 - N+10 Taps (as  generated in Matlab)

Case  1
======
Have 2 separate Input  Data Arrays of length matching to the taps.
i.e.
Array 1 of length N for FIR1.
Array 2 of length N+10 for FIR2.
Feed the incoming  input sample to both the arrays.

Case 2
======
Have a single  Input Data Array of length N+10.
i.e.
Array of length N+10 for both FIR1 & FIR2.
Feed the incoming input sample to the array.
Add 5  zeroes on each side of the filter coefficients for FIR1 to make it length 
/ taps as N+10.
i.e.
FIR1 = [0, 0, 0, 0, 0, N Original Generated  Coefficients, 0, 0, 0, 0, 0]
FIR2 = [N+10 Original  Generated Coefficients]

"Case 1"  brings in complexity in our design and hence we were looking into 
"Case 2" and have certain queries:
1. Will adding zeroes degrade the performance of the filter i.e.  roll-off/
attenuation etc. ?
2.  Will the group delay of the Filter(original generated with added zeroes) 
differ from the Filter(original generated coefficients)  ?

 

 

Kaushal

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