JPS5713808A - Channel selection device - Google Patents

Channel selection device

Info

Publication number
JPS5713808A
JPS5713808A JP8657880A JP8657880A JPS5713808A JP S5713808 A JPS5713808 A JP S5713808A JP 8657880 A JP8657880 A JP 8657880A JP 8657880 A JP8657880 A JP 8657880A JP S5713808 A JPS5713808 A JP S5713808A
Authority
JP
Japan
Prior art keywords
frequency
channel
voltage
divider
division ratio
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
JP8657880A
Other languages
Japanese (ja)
Inventor
Tsugio Itagaki
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 JP8657880A priority Critical patent/JPS5713808A/en
Publication of JPS5713808A publication Critical patent/JPS5713808A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02—Automatic frequency control
    • H03J7/04—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
    • H03J7/06—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant using counters or frequency dividers
    • H03J7/065—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant using counters or frequency dividers the counter or frequency divider being used in a phase locked loop

Landscapes

  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
  • Superheterodyne Receivers (AREA)

Abstract

PURPOSE:To achieve invariably stable reception by providing a frequency-divider control circuit to a channel selection device on a PLL frequency synthesizer system and by varying the frequency division ratio of a variable frequency divider. CONSTITUTION:A frequency-divider control circuit 39 applied with the output voltage of an AFC circuit 6 connected to a tuner 5 is provided with three comparators 30-32 which have threshold levels equivalent to the center voltage of the reversely S-shaped output of an AFC circuit 6, a higher voltage and a lower voltage. If a received-channel frequency shifts from a frequency determined according to a prescribed frequency division ratio in the reception of the desired channel, the frequency division ratio of a variable frequency divider 8' is so varied that the AFC output voltage has the center value of the reversely S-shaped output. Thus, the desired- channel frequency is received stably all the time.
JP8657880A 1980-06-27 1980-06-27 Channel selection device Pending JPS5713808A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8657880A JPS5713808A (en) 1980-06-27 1980-06-27 Channel selection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8657880A JPS5713808A (en) 1980-06-27 1980-06-27 Channel selection device

Publications (1)

Publication Number Publication Date
JPS5713808A true JPS5713808A (en) 1982-01-23

Family

ID=13890881

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8657880A Pending JPS5713808A (en) 1980-06-27 1980-06-27 Channel selection device

Country Status (1)

Country Link
JP (1) JPS5713808A (en)

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