| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method and a circuit for effectively suppressing an interference signal. <P>SOLUTION: A TV signal converted into an intermediate frequency is demodulated into an in-phase signal (I) by an I/Q demodulator in order to suppress interference signals from adjacent TV channels, and demodulated into an orthogonal signal (Q) using a signal shifted in phase by a phase angleπ/2 relative to the signal. The in-phase signal (I) is filtered by a first Hilbert of a Hilbert filter pair having an even symmetrical impulse response. The orthogonal signal (Q) is filtered by a second Hilbert filter of the Hilbert filter pair having a ununiform symmetrical impulse response. The Hilbert-filtered orthogonal signal (Q) is added to the in-phase signal (I) by an adder 21 in order to obtain a video output signal (SVideo). The Hilbert-filtered orthogonal signal (Q) is subtracted from the in-phase signal (I) by a subtractor in order to obtain a sound output signal (SSound). <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
