JPS6457854A - Automatic frequency control circuit - Google Patents

Automatic frequency control circuit

Info

Publication number
JPS6457854A
JPS6457854A JP62213991A JP21399187A JPS6457854A JP S6457854 A JPS6457854 A JP S6457854A JP 62213991 A JP62213991 A JP 62213991A JP 21399187 A JP21399187 A JP 21399187A JP S6457854 A JPS6457854 A JP S6457854A
Authority
JP
Japan
Prior art keywords
sweeping
frequency
synchronization
start point
pull
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
JP62213991A
Other languages
Japanese (ja)
Inventor
Hideto Furukawa
Yoshiharu Tozawa
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 JP62213991A priority Critical patent/JPS6457854A/en
Publication of JPS6457854A publication Critical patent/JPS6457854A/en
Pending legal-status Critical Current

Links

Landscapes

  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

PURPOSE:To contrive the shortening of the frequency pull-in time, by moving a sweeping start point to at least two frequencies apart from the oscillating frequency at synchronization step-out in response to the output detecting the synchronism step-out from a lock detector so as to execute frequency locking. CONSTITUTION:A sweeping circuit 32 moves the sweeping start point to two frequencies sequentially apart from the oscillating frequency at the synchronization step-out in response to the output detecting the of synchronization step-out from a lock detection circuit 19. That is, when a quasi-synchronization carrier recovery circuit, the frequency lower than the oscillating frequency fc by the hold range at the out of synchronization at first is used as the sweeping start point to apply sweeping and when the synchronization cannot be taken even therewith, the frequency lower than the oscillating frequency fc by a value larger than the hold range is used as the sweeping start point to apply sweeping for frequency pull-in. The frequency pull-in is executed in a short time by the unidirectivity of the sweeping.
JP62213991A 1987-08-27 1987-08-27 Automatic frequency control circuit Pending JPS6457854A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62213991A JPS6457854A (en) 1987-08-27 1987-08-27 Automatic frequency control circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62213991A JPS6457854A (en) 1987-08-27 1987-08-27 Automatic frequency control circuit

Publications (1)

Publication Number Publication Date
JPS6457854A true JPS6457854A (en) 1989-03-06

Family

ID=16648447

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62213991A Pending JPS6457854A (en) 1987-08-27 1987-08-27 Automatic frequency control circuit

Country Status (1)

Country Link
JP (1) JPS6457854A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0336849A (en) * 1989-07-03 1991-02-18 Fujitsu Ltd Costas loop type demodulating system
JPH06237277A (en) * 1993-02-09 1994-08-23 Nec Corp Psk carrier signal regenerating device
JP2011109472A (en) * 2009-11-18 2011-06-02 Toshiba Corp Demodulator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0336849A (en) * 1989-07-03 1991-02-18 Fujitsu Ltd Costas loop type demodulating system
JPH06237277A (en) * 1993-02-09 1994-08-23 Nec Corp Psk carrier signal regenerating device
JP2011109472A (en) * 2009-11-18 2011-06-02 Toshiba Corp Demodulator

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