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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

I don't see an indication, that the said 6 dB loss is caused by the FIR filter. But there seems to be a considerable pass band ripple respectively peaking that can't be explained by a FIR filter characteristic. So I guess there's rather a problem with your measurement setup, that hasn't been described in this post (may be otherwhere?).

Did you perform a measurement without the FIR filter? Do we see simply the 6dB loss from 50 ohm impedance matching?