Title:
FREQUENCY MODULATION CIRCUIT
Document Type and Number:
Japanese Patent JP2008193665
Kind Code:
A
Abstract:
To provide a frequency modulation circuit 1 which outputs a highly accurate frequency modulation signal regardless of variation in characteristics of a VCO 15.
A correction value calculation unit 17 calculates a correction value Vt2 on the basis of a voltage value (Vtx-Vt1) resulting from subtracting a control voltage Vt1 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 Vt2. An addition unit 13 outputs a control voltage Vt3 resulting from adding the control voltage Vt1 and the amplified correction value Vt2 to the VCO 15 via a DAC 14.
Inventors:
KATO AKIRA
ISHIDA KAORU
ISHIDA KAORU
Application Number:
JP2007339961A
Publication Date:
August 21, 2008
Filing Date:
December 28, 2007
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03C3/09
Attorney, Agent or Firm:
Shiro Ogasawara
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