DIGITAL BROADCAST RECEIVING APPARATUS

摘要

IN A DIGITAL BROADCAST RECEIVING APPARATUS FOR AMPLIFYING A RECEIVED MODULATED DIGITAL SIGNAL WAVE RF WITH AUTOMATICALLY ADJUSTED GAIN AND DEMODULATING THE MODULATED SIGNAL WAVE TO A DIGITAL SIGNAL SDMD, A TUNER (2) FREQUENCY-CONVERTS THE MODULATED DIGITAL SIGNAL WAVE SRF TO GENERATE A FIRST MODULATED SIGNAL SMA. A FIRST AUTOMATIC GAIN CONTROL AMPLIFICATION UNIT AGC1 CONTROLS GAIN OF THE TUNER (2) TO MAKE A LEVEL OF THE FIRST MODULATED SIGNAL SMA AT THE FIRST PREDETERMINED LEVEL.AN A/D CONVERTER (3) CONVERTS THE FIRST MODULATED SIGNAL SMA INTO A SECOND MODULATED SIGNAL SMD. A DEMODULATOR (7) DEMODULATES THE SECOND MODULATED SIGNAL SDD. A SECOND AUTOMATIC GAIN CONTROL AMPLIFIER AGC2A GENERATES A SECOND DEMODULATED DIGITAL SIGNAL SMDA WHERE FREQUENCY FLUCTUATIONS INCLUDED IN THE DIGITAL MODULATED WAVE SRF ARE ELIMINATED.(FIG 1)