JPS57207431A - Automatic frequency controlling circuit - Google Patents

Automatic frequency controlling circuit

Info

Publication number
JPS57207431A
JPS57207431A JP56092507A JP9250781A JPS57207431A JP S57207431 A JPS57207431 A JP S57207431A JP 56092507 A JP56092507 A JP 56092507A JP 9250781 A JP9250781 A JP 9250781A JP S57207431 A JPS57207431 A JP S57207431A
Authority
JP
Japan
Prior art keywords
voltage
frequency
level
considerably
controlling circuit
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
JP56092507A
Other languages
Japanese (ja)
Inventor
Kunio Kaneko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
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, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP56092507A priority Critical patent/JPS57207431A/en
Publication of JPS57207431A publication Critical patent/JPS57207431A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop

Landscapes

  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

PURPOSE:To improve defect of an AFC loop having a very large time constant, by monitoring an output level of a voltage controlled oscillator and disconnecting the AFC loop when the level is a specified value or below. CONSTITUTION:If an oscillation frequency of a voltage controlled oscillator 2 is considerably shifted at the application or momentary interruption of power supply, the large shift in the oscillating frequency is detected by suitably setting the characteristics of a BPF 8 and a level detector 9. A switch 10 is activated with the detected output and the oscillated voltage of the oscillator 2 is fixed to a voltage of a reference voltage generator 11. Thus, the time of oscillation when the frequency is greatly shifted can considerably be reduced.
JP56092507A 1981-06-16 1981-06-16 Automatic frequency controlling circuit Pending JPS57207431A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56092507A JPS57207431A (en) 1981-06-16 1981-06-16 Automatic frequency controlling circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56092507A JPS57207431A (en) 1981-06-16 1981-06-16 Automatic frequency controlling circuit

Publications (1)

Publication Number Publication Date
JPS57207431A true JPS57207431A (en) 1982-12-20

Family

ID=14056218

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56092507A Pending JPS57207431A (en) 1981-06-16 1981-06-16 Automatic frequency controlling circuit

Country Status (1)

Country Link
JP (1) JPS57207431A (en)

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