An AM/TV/FM Stereo Radio IC Including IF Filters For A DTS

A single-chip AM/TV/FM stereo radio IC including IF (intermediate frequency) filters for a digital tuning system has been developed. The IF filter center frequency is controlled by new low-noise, low-distortion equivalent resistor circuits. Even though the value of resistors varies naturally, the center frequency can be fixed. Consequently, a radio IC including IF filters can be used for a DTS (digital tuning system), and peripheral components and production costs are reduced.