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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

What I want is no additional attenuation besides the filter characteristic. I do not have modelsim, but I can provide some data I collected when trying to find out the exact behavior of the FIR (these are pics from an agilent oscilloscope and the signal tap II logic analyzer).

Especially on the pics from the logic analyzer you can see that the output signal of the filter is missing something, occupying only half of the scaling space.