| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency modulation circuit 1 which outputs a highly accurate frequency modulation signal regardless of variation in characteristics of a VCO 15. SOLUTION: A correction value calculation unit 17 calculates a correction value Vt<SB>2</SB>on the basis of a voltage value (Vtx-Vt<SB>1</SB>) resulting from subtracting a control voltage Vt<SB>1</SB>generated by a control voltage generation unit 11 from a control voltage Vtx at a time when a sensitivity of the VCO 15 becomes maximum. A variable amplification unit 18 amplifies the correction value Vt<SB>2</SB>. An addition unit 13 outputs a control voltage Vt<SB>3</SB>resulting from adding the control voltage Vt<SB>1</SB>and the amplified correction value Vt<SB>2</SB>to the VCO 15 via a DAC 14. COPYRIGHT: (C)2008,JPO&INPIT
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