| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency control circuit that is excellent for a countermeasure against interference. SOLUTION: The frequency control circuit comprises: a local oscillator 118; a mixer 103 mixing an input signal and a local oscillation signal from the local oscillator; a high frequency side band-variable band pass filter 111 and a low frequency side band-variable band pass filter 112 filtering an output of mixer 103; a subtractor calculating an intensity difference between passage signals of both band pass filters 111 and 112; an accumulation circuit accumulating an output of a subtractor and supplying the accumulation value to the local oscillator 118 as a correction signal indicating a correction amount of an oscillating frequency of the local oscillator; and a filter control device 115 narrowing, in cooperation, a pass band width of both band pass filters 111 and 112 when an absolute value of the difference calculated by the subtractor becomes not more than a reference level. COPYRIGHT: (C)2012,JPO&INPIT |
