| 摘要 |
PROBLEM TO BE SOLVED: To shorten a lockup time when a VCO is switched over in an oscillating device provided with two VCOs(voltage controlled oscillator). SOLUTION: A positive polarity VCO 11 and a negative polarity VCO 12 which are different in a frequency range are installed. Corresponding to output frequency to be set of an output frequency signal S1, the VCOs 11, 12 are turned on and off. Corresponding to the polarities of the VCOs 11, 12, the polarity of a phase comparison part 17 is switched over. Difference due to the switching of the VCOs is prevented from being generated in a control voltage Vs of a signal S3 to be supplied to the VCOs 11, 12.
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