Patent ID: 6968173

Claim:
A tuner comprising a frequency changer for converting an input signal to an output signal of a predetermined fixed intermediate frequency, an intermediate frequency filter for filtering said output signal and having at least one electronically adjustable filtering characteristic, and a controller for adjusting said at least one adjustable characteristic to achieve a predetermined filtering performance, wherein said intermediate frequency filter comprises at least one first tuned circuit having a first electronically adjustable component for adjusting said at least one filtering characteristic, and wherein said controller comprises: a local oscillator having a second tuned circuit for determining a frequency of oscillation of said local oscillator, said second tuned circuit having a same circuit as said at least one first tuned circuit and having a second electronically adjustable component of a same type as said first electronically adjustable component; and a phase locked loop for comparing said frequency of oscillation of said local oscillator with a reference frequency to generate a control signal for controlling said first and second electronically adjustable components.