| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a demodulation circuit that suitably demodulates an audio frequency signal by eliminating disadvantages derived from diodes. <P>SOLUTION: One end t1 of a secondary coil 2out of an input transformer 2 is connected to COM of an analog switch 3, and an opposite end t2 of the secondary coil 2out is connected to COM of an analog switch 4. A rectangular wave REC with a duty ratio of 50% having the same frequency as a carrier signal is input into CNT of the analog switches 3 and 4. One end t3 of a loading resistor 5 is connected to NC of the analog switch 3 and NO of the analog switch 4, and an opposite end t4 of the loading resistor 5 is connected to NO of the analog switch 3 and NC of the analog switch 4. A difference between an audio frequency signal appearing at the one end t3 and an audio frequency signal appearing with phase inversion at the opposite end t4 is amplified. <P>COPYRIGHT: (C)2013,JPO&INPIT |
