RECEIVER DEVICE FOR MULTI-SYSTEM

摘要

PURPOSE:To improve the handling performance of a reciver device together with reduction of its cost by deciding automatically the modulated wave under broadcasting among those mixed anallog and digital modulated waves and demodulating properly the decided modulated wave. CONSTITUTION:The IF signals are acquired through an RF amplifier 2, a tuner 3 and a local oscillator 4, and the gains of the IF signals are controlled by an AGC amplifier 5. These IF signals are inputted to a frequency error (DELTAf) detecting circuit 6, an analog modulated wave demodulator 100 and a digital modulated wave demodulator 200 respectively. The circuit 6 detects the frequency error (frequency error information) of the IF signals and applies the frequency control signal to the oscillator 4 via a switch 4 (only when the analog modulated signal is received). A digital modulated wave deciding circuit 300 decides whether the signal of the modulator 200 is normal or not. If so, the received signal is decided as a digital modulated wave and a switch 7 is turned off together with a switch 8 is turned toward a digital decoding circuit 201. Otherwise the switch 7 is turned on and the switch 8 is turned toward a signal processing part 101.