| 摘要 |
Provided is a variable RF filter that receives differential high-frequency signals at differential input terminals (501, 502) and passes high-frequency signals having frequencies around a desired frequency. In this variable RF filter, first passive mixers (901,..., 904), which are driven by clock signals of rectangular waves having an arbitrarily specified frequency, are connected in parallel to the signal lines between the differential input terminals (501, 502) and differential output terminals (918, 919), and the respective loads of the first passive mixers (901,..., 904) are constituted by inductors (903,..., 906). Further, odd-multiple wave Lo signals (for example, three-time wave Lo signals), the frequencies of which are an odd multiple of (for example, three times) the frequency of an Lo signal that is the fundamental of the high-frequency signals passed, are used as the clock signals for driving the respective first passive mixers (901,..., 904). |
