Before revision: The goal of a roofing filter is to limit the passband of the first intermediate frequency (IF) stage to about 6-20 kHz, so that overloading and distortions by the following amplifier stages and mixers are reduced.
After revision: The goal of a roofing filter is to limit the passband of the first intermediate frequency (IF) stage to about 6-20 kHz, so that overloading and distortion by the following amplifier stages and mixers are reduced.