| 摘要 |
PURPOSE:To make it possible to receive the FM broadcasting wave also by adding a prescribed circuit to the wide band receiver of the double mixture system. CONSTITUTION:The wide band receiver of the double mixture system is provided with fixed oscillator 28, mixer 27 and switching circuit 15. Now, the switching circuit is switched when the FM broadcasting wave is received. Then, the signal from wide band amplifier 1 is converted to the first IF signal by mixer 2 and tuning oscillator 3 and is supplied to mixer 5 through BPF4. This converted signal is mixed with the signal of fixed oscillator 6 and is converted to the second TV IF signal and is supplied to mixer 27 through FI amplifier 7 and switching circuit 15. In mixer 27, this converted signal is mixed with the signal of fixed oscillator 27 and is converted to the third FM IF signal. Next, this output is detected through IF amplifier 9 by sound FM detector 10 and is amplified by 11 and is supplied to speaker 12. Thus, the FM wave can be received besides VHF and UHF-band TV waves. |
