PURPOSE: To reduce the cost and to prevent beat noises by sharing the most part of local oscillators consisting of phase locked loops(PLL).
CONSTITUTION: A switching control signal is applied on changeover switches S1-S3 from a control circuit 18, and the change over switches S1-S3 are interactively and alternately changed over. Consequently, a programmable frequency divider 14, a phase difference detector 15 and a low pass filter 17 are set in common, and PLL of two systems including a first local oscillator 4 or a second local oscillator 11 are alternately formed. On the other hand, frequency division rate data N which are synchronized with the switching control signals outputted from the control circuit 18 to the switches S1-S3 and are outputted from the control circuit 18 to the programmable frequency divider 14 are alternately switched. Tuning is executed by local oscillation outputs based on frequency division rate data N1 and N2 in first and second tuners. Thus, the cost is reduced and the beat noise is prevented.
KOBAYASHI HIDEAKI
SHISHIDO OSAMU
MIYANO KOICHI
MATSUMOTO ISAO
