JPS5680932A - Phase synchronizing circuit - Google Patents

Phase synchronizing circuit

Info

Publication number
JPS5680932A
JPS5680932A JP15842079A JP15842079A JPS5680932A JP S5680932 A JPS5680932 A JP S5680932A JP 15842079 A JP15842079 A JP 15842079A JP 15842079 A JP15842079 A JP 15842079A JP S5680932 A JPS5680932 A JP S5680932A
Authority
JP
Japan
Prior art keywords
phase
capacitor
pass filter
low
input signal
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
JP15842079A
Other languages
Japanese (ja)
Inventor
Kiyoshi Takayama
Koji Uno
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP15842079A priority Critical patent/JPS5680932A/en
Publication of JPS5680932A publication Critical patent/JPS5680932A/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
    • H03L7/10—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range
    • H03L7/107—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth
    • H03L7/1075—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth by changing characteristics of the loop filter, e.g. changing the gain, changing the bandwidth

Abstract

PURPOSE:To improve phase leading-in characteristics by shortening the discharge time of a capacitor for a low-pass filter sufficiently, by forming a short circuit by providing a transistor in parallel to the capacitor. CONSTITUTION:Phase comparator 1 makes a phase comparison between output 6 of voltage control oscillator 3 and input signal 4 and generates control voltage 5 that corresponds to their phase difference. Control voltage 5, after passing through low-pass filter 2, enters voltage control oscillator 3. Oscillator 3 oscillates to generate output signal 6 synchronizing with input signal 4 in response to control voltage 5. Further, transistors Q1 and Q2 operating with gate signal 7 synchronize input signal 4 and output signal 6 with each other to prevent the deterioration of phase leading-in characteristics. Furthermore, transistor Q3 is provided in parallel to capacitor C2 of low-pass filter 2 to form a short circuit when Q1 operates, eliminating residual charge.
JP15842079A 1979-12-06 1979-12-06 Phase synchronizing circuit Pending JPS5680932A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15842079A JPS5680932A (en) 1979-12-06 1979-12-06 Phase synchronizing circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15842079A JPS5680932A (en) 1979-12-06 1979-12-06 Phase synchronizing circuit

Publications (1)

Publication Number Publication Date
JPS5680932A true JPS5680932A (en) 1981-07-02

Family

ID=15671358

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15842079A Pending JPS5680932A (en) 1979-12-06 1979-12-06 Phase synchronizing circuit

Country Status (1)

Country Link
JP (1) JPS5680932A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4559505A (en) * 1983-01-04 1985-12-17 Motorola, Inc. Frequency synthesizer with improved priority channel switching

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4559505A (en) * 1983-01-04 1985-12-17 Motorola, Inc. Frequency synthesizer with improved priority channel switching

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