| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the interference in a specific channel without generating bad influence in a channel having a relatively high frequency, in a PLL circuit 31 used for a superheterodyne system television receiver. <P>SOLUTION: In a phase comparator 34, a reference signal oscillating circuit 33 for generating a reference signal to be compared with an LO signal is constituted so as to be provided with an oscillation circuit 41, and a serial circuit of an oscillator 37 corresponding to a predetermined IF signal frequency and correction capacity element 38 together with another correction capacity element 39 and a switch 40. Only when the specific channel having the interference is received, the switch 40 is turned on or off to shift the frequency of the reference signal by several tens of kHz. Accordingly, image quality deterioration in another channel can be prevented while reducing the beat in the specific channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
