JPS54128624A - Automatic frequency control unit - Google Patents

Automatic frequency control unit

Info

Publication number
JPS54128624A
JPS54128624A JP3606978A JP3606978A JPS54128624A JP S54128624 A JPS54128624 A JP S54128624A JP 3606978 A JP3606978 A JP 3606978A JP 3606978 A JP3606978 A JP 3606978A JP S54128624 A JPS54128624 A JP S54128624A
Authority
JP
Japan
Prior art keywords
circuit
signal obtained
oscillation frequency
local oscillation
malfunction prevention
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
JP3606978A
Other languages
Japanese (ja)
Inventor
Toshio Murakami
Masaru Noda
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP3606978A priority Critical patent/JPS54128624A/en
Publication of JPS54128624A publication Critical patent/JPS54128624A/en
Pending legal-status Critical Current

Links

Landscapes

  • Television Receiver Circuits (AREA)

Abstract

PURPOSE: To make stable the drawing-in of the circuit using a simple synchronous detection, by adding the circuit which can extend the respective drawing range for the higher and lower local variation with the malfunction prevention circuit, in the AFC circuit of the local oscillation frequency of a TV receiver.
CONSTITUTION: In the AFC circuit providing the malfunction prevention circuit 4 which automatically controls the local oscillation frequency of the tuner of a TV receiver and prevents the malfunction due to the self audio signal caused when the local oscillation frequency is varied toward higher, the superposition and mixing circuit 12 superimposing and mixing the synchronous signal obtained from the synchronous separation circuit 10 connected to the video synchronizing detection circuit 9 and the blanking signal obtained from the blanking signal obtained from the blanking signal generating circuit 11, is provided. Further, the rectifying and smoothing circuit 13 rectifying and smoothing the mixed signal obtained from the circuit 12 is provided, the DC voltage of the circuit 13 is used as the control voltage of the malfunction prevention circuit 4 to extend the drawing range of higher and lower local variation.
COPYRIGHT: (C)1979,JPO&Japio
JP3606978A 1978-03-30 1978-03-30 Automatic frequency control unit Pending JPS54128624A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3606978A JPS54128624A (en) 1978-03-30 1978-03-30 Automatic frequency control unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3606978A JPS54128624A (en) 1978-03-30 1978-03-30 Automatic frequency control unit

Publications (1)

Publication Number Publication Date
JPS54128624A true JPS54128624A (en) 1979-10-05

Family

ID=12459431

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3606978A Pending JPS54128624A (en) 1978-03-30 1978-03-30 Automatic frequency control unit

Country Status (1)

Country Link
JP (1) JPS54128624A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5040225A (en) * 1973-08-16 1975-04-12

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5040225A (en) * 1973-08-16 1975-04-12

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