Image Number 2 for United States Patent #7548129.
An integrated tuner includes circuitry to receive a television signal, a quadrature mixer coupled to the output of the circuitry, a polyphase filter coupled to the output of the quadrature mixer, a relaxation oscillator, and a digital calibration module. The relaxation oscillator generates a clock having a period that is directly proportional to the on-chip RC time constant. The clock is fed into a counter of the digital calibration module. The counter is started and stopped at predefined time intervals by a finite state machine. The finite state machine updates the calibration code based on a successive approximation algorithm according to the end count results received from the counter. The digital calibration module outputs the updated calibration code to the polyphase filter and to the relaxation oscillator.