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Altera_Forum
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15 years ago

Unwanted offset attenuation in FIR filters

My FIR is now working so far - thanks to Altera Guru "MSchmitt" - but I still have two problems left. Please have a look at the attached pictures - there is an unwanted offset attenuation of 6dB in t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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What should I try next?

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Depends on what you're trying to achieve, which isn't actually clear from your post. I also don't see, what the shown "miniVNA" is exactly doing. The phase waveform e.g. looks strange, should be a sawtooth rather than a triangle.

To test the FIR filter without the analog signal path, a ModelSim testbench would be the approriate means. Simulation is also the best way to clarify all data type and signal scaling doubts.