JPS6359008A - Fm modulation circuit - Google Patents

Fm modulation circuit

Info

Publication number
JPS6359008A
JPS6359008A JP20228586A JP20228586A JPS6359008A JP S6359008 A JPS6359008 A JP S6359008A JP 20228586 A JP20228586 A JP 20228586A JP 20228586 A JP20228586 A JP 20228586A JP S6359008 A JPS6359008 A JP S6359008A
Authority
JP
Japan
Prior art keywords
output
voltage
signal
frequency divider
controlled oscillator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP20228586A
Other languages
Japanese (ja)
Inventor
Takeshi Toyoda
Original Assignee
Nec Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nec Corp filed Critical Nec Corp
Priority to JP20228586A priority Critical patent/JPS6359008A/en
Publication of JPS6359008A publication Critical patent/JPS6359008A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE: To always bring a reference DC level of a modulation input signal to be at the center of an output frequency by changing the frequency division ratio of an output of a voltage controlled oscillator inputted to a phase comparator in response to a mean voltage of the modulation input signal by means of a variable frequency divider.
CONSTITUTION: A mean voltage detection circuit 7 detects a mean voltage of a modulation signal inputted to the voltage controlled oscillator 1. Then the detected analog mean voltage is converted into a digital signal by an A/D converter 8 and the result is inputted to a variable frequency divider 6. Then the frequency dividing ratio of the variable frequency divider 6 is subject to variable control so as to be proportional to the mean voltage of the modulation signal. The phase comparator 2 compares the phase of the output of the variable frequency divider 6 with that of the output of the frequency divider 4 and controls the output (modulated signal) frequency of the said voltage controlled oscillator 1 linearly by feeding back the difference signal voltage in response to the phase difference to a control terminal of the voltage controlled oscillator 1. Thus, in modulating a modulation signal having asymmetry, the reference DC level of the modulation signal is the center of the output frequency.
COPYRIGHT: (C)1988,JPO&Japio
JP20228586A 1986-08-27 1986-08-27 Fm modulation circuit Pending JPS6359008A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP20228586A JPS6359008A (en) 1986-08-27 1986-08-27 Fm modulation circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20228586A JPS6359008A (en) 1986-08-27 1986-08-27 Fm modulation circuit

Publications (1)

Publication Number Publication Date
JPS6359008A true JPS6359008A (en) 1988-03-14

Family

ID=16455003

Family Applications (1)

Application Number Title Priority Date Filing Date
JP20228586A Pending JPS6359008A (en) 1986-08-27 1986-08-27 Fm modulation circuit

Country Status (1)

Country Link
JP (1) JPS6359008A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02124607A (en) * 1988-11-02 1990-05-11 Matsushita Electric Ind Co Ltd Synthesized signal generator
JPH04505841A (en) * 1989-03-27 1992-10-08

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02124607A (en) * 1988-11-02 1990-05-11 Matsushita Electric Ind Co Ltd Synthesized signal generator
JPH04505841A (en) * 1989-03-27 1992-10-08

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