| 摘要 |
PROBLEM TO BE SOLVED: To reduce interference between a local oscillation signal and an RF (radio frequency) signal. SOLUTION: This circuit includes two mixers 32, 36 in an orthogonal relation, a phase shifting unit 50 and a local oscillator. The two mixers 32 and 36 are connected with the input port 30 of a radio frequency signal to mix a radio frequency inputted signal to convert into a low frequency. The unit 50 is connected with at least one of the mixers 32 and 36 to phase-shift the local oscillation signal. The local oscillator is constituted of a phase-locked loop including frequency dividers 40 and 44. The output signal of a first voltage controlled oscillator 38 is frequency-multiplied to be a non-integer value N/M-fold by this loop to be a local oscillation signal. Since the frequency of the oscillator 38 is the non-integer multiple of RF, interference from RF is reduced.
|
