GB1493264A - Automatic gain control circuit - Google Patents
Automatic gain control circuitInfo
- Publication number
- GB1493264A GB1493264A GB5098674A GB5098674A GB1493264A GB 1493264 A GB1493264 A GB 1493264A GB 5098674 A GB5098674 A GB 5098674A GB 5098674 A GB5098674 A GB 5098674A GB 1493264 A GB1493264 A GB 1493264A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sync
- transistor
- pedestal
- video signal
- separator
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/52—Automatic gain control
- H04N5/53—Keyed automatic gain control
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
- Control Of Amplification And Gain Control (AREA)
- Picture Signal Circuits (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
1493264 Television automatic gain control HITACHI Ltd 25 Nov 1974 [26 Nov 1973] 50986/74 Heading H3T A television a.g.c. system comprises means for amplifying the television signal containing a composite video signal, means for detecting the composite video signal, a sync. separator, means for modifying the composite video signal so that the pedestal is the most black level and an a.g.c. signal generator connected between the modifying means and the amplifying means to control the gain thereof. The video signal with negative going sync. pulses from the first video amplifier 4, Fig. 1, is connected to a sync. separator transistor 10 and through a switch 103 to an A.G.C. detector transistor 16. A pulse (b) from the sync. separator cancels the sync. pulse, leaving the black level pedestal the most negative going portion of the signal applied to transistor 16. Transistor 16 is biased to just conduct near the tip of the pedestal so that changes in pedestal level change the collector current to develop an A.G.C. voltage across resistor 23. Diode 14 may be replaced by a transistor with resistor 15 connected to its base, Fig. 3 (not shown).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13171073A JPS5435734B2 (en) | 1973-11-26 | 1973-11-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1493264A true GB1493264A (en) | 1977-11-30 |
Family
ID=15064374
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB5098674A Expired GB1493264A (en) | 1973-11-26 | 1974-11-25 | Automatic gain control circuit |
Country Status (5)
Country | Link |
---|---|
JP (1) | JPS5435734B2 (en) |
CA (1) | CA1050160A (en) |
DE (1) | DE2455703C3 (en) |
FR (1) | FR2252717B1 (en) |
GB (1) | GB1493264A (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS50125627A (en) * | 1974-03-19 | 1975-10-02 | ||
JPS5453921A (en) * | 1977-10-07 | 1979-04-27 | Clarion Co Ltd | Automatic gain control circuit for am receiver |
JPS5510277A (en) * | 1978-07-07 | 1980-01-24 | Matsushita Electric Ind Co Ltd | Agc circuit |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE559382A (en) * | 1956-07-20 | |||
JPS5319709Y2 (en) * | 1971-03-22 | 1978-05-25 |
-
1973
- 1973-11-26 JP JP13171073A patent/JPS5435734B2/ja not_active Expired
-
1974
- 1974-11-25 CA CA214,569A patent/CA1050160A/en not_active Expired
- 1974-11-25 DE DE19742455703 patent/DE2455703C3/en not_active Expired
- 1974-11-25 FR FR7438572A patent/FR2252717B1/fr not_active Expired
- 1974-11-25 GB GB5098674A patent/GB1493264A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS5084132A (en) | 1975-07-07 |
FR2252717B1 (en) | 1982-03-19 |
DE2455703A1 (en) | 1975-06-19 |
JPS5435734B2 (en) | 1979-11-05 |
DE2455703C3 (en) | 1978-03-16 |
FR2252717A1 (en) | 1975-06-20 |
CA1050160A (en) | 1979-03-06 |
DE2455703B2 (en) | 1977-07-28 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |