| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic frequency controller which can be miniaturized and integrated by a simple method without using a frequency conversion method. SOLUTION: An in-phase baseband signal outputted from a first low-pass filter 6 is phase-rotated at -90 degrees at a frequency shift by a phase shifter 9, and an output signal of the phase shifter 9 is amplitude-limited by a first limiter circuit 10. A quadrature baseband signal outputted from a second low-pass filter 7 is amplitude-limited by a second limiter circuit 11, and a phase difference in output signal between both the limiter circuits 10, 11 is detected by a phase detector 12. A control circuit 13 controls a voltage-controlled oscillator 4 so that the phase difference to be detected becomes 0 in response to an output signal of the phase detector 12. COPYRIGHT: (C)2007,JPO&INPIT
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