JPS5591270A - Video detection circuit - Google Patents
Video detection circuitInfo
- Publication number
- JPS5591270A JPS5591270A JP16220578A JP16220578A JPS5591270A JP S5591270 A JPS5591270 A JP S5591270A JP 16220578 A JP16220578 A JP 16220578A JP 16220578 A JP16220578 A JP 16220578A JP S5591270 A JPS5591270 A JP S5591270A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- detection circuit
- lpf
- vcont
- phase detection
- 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.)
- Granted
Links
Landscapes
- Television Receiver Circuits (AREA)
Abstract
PURPOSE: To facilitate the channel selection by varying the output level of the circuit for phase detection via the external control function, thus obtaining the steady screen without excluding the pull-in range.
CONSTITUTION: The video detection circuit comprises the mixer circuit, the phase detection circuit, LPF, the variable gain control circuit and others. And the variable gain control circuit is inserted between the phase detection circuit and LPF. The variable gain control circuit functions as follows. That is, the current is made constant for transistors Q5 and Q6 with the same potential secured between input terminals IN1 and IN2 plus the same value given between resistances R3 and R4. Then potential VCONT is given to the bases of Q1 and Q2 through resistance R5. At the same time, the collectors of Q1 and Q3 are connected to power source VCC via resistance R1, and the collectors of Q2 and Q4 are connected to VCC via resistance R2 each. Thus the gain of output terminal OUT1 increases when VCONT is set higher than reference potential VC; while the gain of output terminal OUT2 decreases if VCONT is set lower than VC. This output is supplied to LPF to be then supplied directly to the local oscillator.
COPYRIGHT: (C)1980,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16220578A JPS5591270A (en) | 1978-12-29 | 1978-12-29 | Video detection circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16220578A JPS5591270A (en) | 1978-12-29 | 1978-12-29 | Video detection circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5591270A true JPS5591270A (en) | 1980-07-10 |
JPS6228630B2 JPS6228630B2 (en) | 1987-06-22 |
Family
ID=15749963
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16220578A Granted JPS5591270A (en) | 1978-12-29 | 1978-12-29 | Video detection circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5591270A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0218947U (en) * | 1988-07-22 | 1990-02-08 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS448487Y1 (en) * | 1966-10-18 | 1969-04-04 | ||
JPS5317448A (en) * | 1976-07-30 | 1978-02-17 | Lego As | Connector for assemblying toy |
-
1978
- 1978-12-29 JP JP16220578A patent/JPS5591270A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS448487Y1 (en) * | 1966-10-18 | 1969-04-04 | ||
JPS5317448A (en) * | 1976-07-30 | 1978-02-17 | Lego As | Connector for assemblying toy |
Also Published As
Publication number | Publication date |
---|---|
JPS6228630B2 (en) | 1987-06-22 |
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