Abstract: A direct down conversion receiver includes a signal filter having a selectable frequency response for receiving an input signal. The filtered signal is amplified by a variable gain amplifier, and the amplified signal is received as input by an analog-to-digital converter. The analog-to-digital converter generates a series of digital samples representative of the filtered signal. A controller measures a corresponding peaking ratio of the filtered signal from the series of digital samples for each of a plurality of frequency bands and selects the frequency response of the signal filter as a function of the measured peaking ratios. The signal filter may include an adjustable highpass filter and an adjustable lowpass filter.