Frequency synthesis type tuner for TV receiver - calibrates by information representing tuning voltage values stored in digital type memory

摘要

The tuner includes several electrically variable capacitors (varicap). Calibration is carried out by memorising appropriate information in a digital type memory. Inductors are realised by a printing procedure. Calibration is carried out by correcting a voltage applied to the varicaps starting from the memorised digital information converted by D-A converters. The memorised digital information represents differential values of the tuning voltages w.r.t. a voltage value applied to a varicap circuit of a local oscillator. The inductors are formed on a printed circuit.