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decimation filter for high order decimation rate

Started by itamare1982 November 21, 2011
Hi ALL

I working on application that i need to sample 1.9Khz signal by 1Mhz , its mean 512 OSR - AFTER SIGMA DELTA MODULATION ( FOR SEPARATE the quantization noise from the signal) i need to decimate the signal by decimation rate of 512.
i decided to use CIC filter to decimate by 128 and then cascade more 2 FIR - one as compensator and the other for the phase linearization.

the DC gain in the CIC is a function of the DECIMATION RATE AND THE STAGES so i getting about 100 db in the dc...

i need to create compensation filter to compensate the very large GAIN that i getting in DC ( about 100db).
to get flatness pass band i need to use inverse sinc fir compensator that attenuate by 100 db in the DC...

does some one have another solution to this problem ?
does some one have experience with the inverse sinc filter or nine halfband filters( goodman and carey?
THANK U ALL