JPS5713808A - Channel selection device - Google Patents
Channel selection deviceInfo
- 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
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.
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) |
-
1980
- 1980-06-27 JP JP8657880A patent/JPS5713808A/en active Pending
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