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JordanD's avatar
JordanD
Icon for New Contributor rankNew Contributor
4 years ago

FIR II Decimation Frequency Response

I'm designing a filter with the FIR II IP. Input data rate is 64 MHz and decimation factor is 8. I want the frequency response to be low pass cut off at 3.2 MHz. The confusing thing is whether the ...
CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
4 years ago

Hi,


Sorry for the delay. As I understand it, you are observing different in the FIR IP frequency response vs the plot that you obtained from the simulation. You are expecting some plot with cutoff at 3.2MHz but from your plot, you are observing cutoff ~25MHz.


1. Mind share with me the detailed step to replicate your plots ie at both Matlab and Modelsim? This would be helpful for further debugging and to engage Factory if required.


2. Would you mind to share with me what are the changes to the default IP generated files if there is any?


3. Have you had a chance to cross check with Matlab FIR to serve as a golden reference?


Please let me know if there is any concern. Thank you.