| 摘要 |
PURPOSE:To reduce the cost by using a high frequency amplifier and a mixer in common and using the same intermediate frequency band at a similar occupied frequency band and utilizing an FM demodulator so as to constitute an AM demodulator thereby decreasing the redundancy of the circuit constitution. CONSTITUTION:A broad band high frequency amplifier 6 and a mixer 7 are used in common both at satellite broadcast signal reception and ground broadcast reception, both the broadcast signals are converted into the same intermediate frequency by a local oscillator 8 and the occupied frequency band is made equal to eliminate an undesired signal through an intermediate frequency filter 10. Then a phase synchronizing circuit 11 acting like the FM demodulator at the satellite broadcast signal reception is used for recovering a carrier at the ground broadcast signal reception and operated as the AM demodulator using a multiplier 14 applying multiplication with a ground broadcast signal. Thus, the satellite broadcast signal (FM signal) and the ground broadcast signal (AM signal) are received and demodulated by the same reception system.
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