| 摘要 |
An IC of a front end circuit which can be ready for various television broadcasting systems is provided. The front end circuit includes tuning circuits 12A to 12C and 14A to 14C and high frequency amplifiers 13A to 13C individually corresponding to a plurality of reception bands of television broadcasts. The front end circuit further includes a switch circuit 11 for selectively supplying reception signals to the tuning circuits 12A to 12C, and a switch circuit 15 for selectively extracting outputs of the tuning circuits 14A to 14C. The front end circuit further includes mixer circuits 21I and 21Q to which an output of the switch circuit 15 is supplied, and a PLL 30 for supplying local oscillation signals SLOI and SLOQ having phases orthogonal to each other to the mixer circuits 21I and 21Q. The front end circuit further includes a complex band-pass filter 24 to which outputs of the mixer circuits 21I and 21Q are supplied, and an output circuit 25 for mathematically operating an output of the complex band-pass filter 24 and outputting an intermediate frequency signal SIF. |
