| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a filter circuit that can appropriately control a frequency characteristic to adjust a signal level even if there are a plurality of signals in different frequency bands and the signals have a level difference. <P>SOLUTION: The filter circuit includes: a filter section having a variable cutoff frequency and attenuation to an input signal; and a control section for setting the cutoff frequency and attenuation of the filter section. The control section includes: a first signal level detector for detecting a signal level of a first frequency band of the input signal; a second signal level detector for detecting a signal level of a second frequency band of the input signal different from the first frequency band; a signal level comparator for comparing outputs of the first signal level detector and second signal level detector; and a controller for setting the cutoff frequency and attenuation of the filter section on the basis of an output from the signal level comparator. <P>COPYRIGHT: (C)2013,JPO&INPIT |
