A method for tuning a filter is provided. The amplitude of a first signal (I.sub.1) is compared with the amplitude of a comparison signal. The first signal is generated with a first filter, which receives a first input signal, and there is a phase difference between the first signal (I.sub.1) and the comparison signal. A tuning signal is then generated based on differences between the amplitudes of the first signal (I.sub.1) and the comparison signal. The tuning signal compensates for any phase and/or amplitude offset in the first signal (I.sub.1).