Title:
FREQUENCY MODULATION CURRENT GENERATING CIRCUIT AND FREQUENCY MODULATION METHOD
Document Type and Number:
Japanese Patent JP3158689
Kind Code:
B2
Abstract:
PURPOSE: To suppress the effect in sensitivity dispersion due to dispersion in components of a VCO by implementing frequency modulation based on an original signal and a shift current obtained by a carrier current without temperature dependency decreased by a prescribed reduction rate.
CONSTITUTION: A reference current IREF without temperature dependency is fed to a carrier frequency setting current generating circuit 2. An input carrier frequency setting current ICAR from the circuit 2 is inputted to a current 1/N circuit 32 via a switch circuit 31. The current ICAR is branched to 1/N in the circuit 32 and a half shift current IHHS is generated and the current IHHS is outputted to an adder 5. Furthermore, a luminance signal voltage current conversion circuit 4 adjusts a prescribed frequency shift with respect to a luminance signal Y of a video signal to generate a frequency shift setting current IDEV in response to the amplitude of the signal Y and the result is outputted to the adder 5. Thus, the currents ICAR, IHHS, IDEV are added by the adder 5 and the sum is outputted to an FM modulation circuit 6, and frequency modulation to a luminance signal deviated by 1/2fH is implemented by the current sum.
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Inventors:
Takeshi Ikeda
Futao Yamaguchi
Futao Yamaguchi
Application Number:
JP20845092A
Publication Date:
April 23, 2001
Filing Date:
July 13, 1992
Export Citation:
Assignee:
ソニー株式会社
International Classes:
G11B20/06; H03C3/16; H04N5/922; H04N9/84; (IPC1-7): H04N5/922; H03C3/16
Domestic Patent References:
| JP1238206A | ||||
| JP4304084A | ||||
| JP4304085A |
Attorney, Agent or Firm:
Takahisa Sato