JPS57124920A - Automatic frequency controlling circuit - Google Patents
Automatic frequency controlling circuitInfo
- Publication number
- JPS57124920A JPS57124920A JP1095881A JP1095881A JPS57124920A JP S57124920 A JPS57124920 A JP S57124920A JP 1095881 A JP1095881 A JP 1095881A JP 1095881 A JP1095881 A JP 1095881A JP S57124920 A JPS57124920 A JP S57124920A
- Authority
- JP
- Japan
- Prior art keywords
- pulse
- circuit
- dropout
- output
- 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
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
- Synchronizing For Television (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Abstract
PURPOSE:To prevent malfunction of an AFC circuit against a dropout, by forming an inhibition pulse from an output of a voltage controlled oscillator and controlling the operation of a phase comparator by using said pulse. CONSTITUTION:When a dropout 63 is included in a television signal (g) inputted from an input terminal 18, a synchronizing separation circuit 14 outputs a signal 60 corresponding to the dropout 63 as a horizontal synchronizing signal. On the other hand, an inhibiting pulse (i) inhibits the operation of a pulse generating circuit 15 for phase comparison at periods other than the period when a potential waveform (n) of a point 25 of circuit reaches a potential of 62 from the fall of a synchronizing separation output (m). Thus, when the inhibiting pulse (i) is present, even if the output (m) of the circuit 14 is changed, no the circuit 15 is operated and no phase comparison pulse (j) is generated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1095881A JPS57124920A (en) | 1981-01-27 | 1981-01-27 | Automatic frequency controlling circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1095881A JPS57124920A (en) | 1981-01-27 | 1981-01-27 | Automatic frequency controlling circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS57124920A true JPS57124920A (en) | 1982-08-04 |
Family
ID=11764686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1095881A Pending JPS57124920A (en) | 1981-01-27 | 1981-01-27 | Automatic frequency controlling circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57124920A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61206371A (en) * | 1985-03-06 | 1986-09-12 | フィリップス エレクトロニクス ネムローゼ フェンノートシャップ | Line synchronization circuit and image display unit containing line deflection circuit |
-
1981
- 1981-01-27 JP JP1095881A patent/JPS57124920A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61206371A (en) * | 1985-03-06 | 1986-09-12 | フィリップス エレクトロニクス ネムローゼ フェンノートシャップ | Line synchronization circuit and image display unit containing line deflection circuit |
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