GB525284A - Automatic control of television receiving systems - Google Patents
Automatic control of television receiving systemsInfo
- Publication number
- GB525284A GB525284A GB5214/39A GB521439A GB525284A GB 525284 A GB525284 A GB 525284A GB 5214/39 A GB5214/39 A GB 5214/39A GB 521439 A GB521439 A GB 521439A GB 525284 A GB525284 A GB 525284A
- Authority
- GB
- United Kingdom
- Prior art keywords
- voltage
- control
- signal
- valve
- anode
- 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
- 238000010586 diagram Methods 0.000 abstract 1
- 238000005562 fading Methods 0.000 abstract 1
- 238000009499 grossing Methods 0.000 abstract 1
- 238000005286 illumination Methods 0.000 abstract 1
- 230000010355 oscillation Effects 0.000 abstract 1
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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/22—Automatic control in amplifiers having discharge tubes
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Systems (AREA)
- Picture Signal Circuits (AREA)
Abstract
525,284. Automatic control of television receiving apparatus. HAZELTINE CORPORATION. Feb. 16, 1939, No. 5214. Convention date, March 15, 1938. [Class 40 (v)] In a television system in which the intensity of general illumination is transmitted by the average intensity of the carrier, the signal during the frame retrace period, which is modulated by synchronizing pulses only, is used to provide a controlling potential which is responsive to the intermediate amplitude-level of the modulation envelope of the signals, but independent of its " timing " characteristics. The derived potential may be used for automatic volume selectivity, or tuning control, but as described is applied to volume control only. The signal output from detector 15, Fig. 1, is applied to valve 20, and if the input signal is as shown in Fig. 2 the anode current of valve 20 is as indicated in Fig. 4. The time period of condenser 26 and resistance 25 is long compared with the line blanking periods, but short compared with the frame blanking periods, so that the voltage developed across condenser 26 is of the form shown in Fig. 5. This voltage is subtracted from the anode voltage supplied at B so that a voltage as indicated in Fig. 6 is obtained by peak rectifying anode 21 reversed by valve 22 and applied through smoothing filters 30, 31 as a control voltage to the radio frequency amplifier 12, the oscillation modulator 13, and the intermediate frequency amplifier 14. Battery 33 is provided to compensate for the +B voltage. The control voltage is fairly steady and as it is derived from the unmodulated parts of the carrier, it is independent of light modulation components. The diagrams A in Figs 2, 5 and 6 indicate a signal of normal strength and those at A<SP>1</SP> a faded signal and it will be seen that the control voltage P, P<SP>1</SP> varies with fading.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US195955A US2240533A (en) | 1938-03-15 | 1938-03-15 | Automatic control of television receiving systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB525284A true GB525284A (en) | 1940-08-26 |
Family
ID=22723519
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB5214/39A Expired GB525284A (en) | 1938-03-15 | 1939-02-16 | Automatic control of television receiving systems |
Country Status (5)
Country | Link |
---|---|
US (1) | US2240533A (en) |
CH (1) | CH215258A (en) |
FR (1) | FR851588A (en) |
GB (1) | GB525284A (en) |
NL (1) | NL59187C (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2480842A (en) * | 1945-03-06 | 1949-09-06 | Sperry Corp | Automatic gain-control system |
US2476523A (en) * | 1945-06-27 | 1949-07-19 | Rca Corp | Fast-acting automatic volume control and sync pulse reshaping circuit |
US2492363A (en) * | 1946-02-01 | 1949-12-27 | Bell Telephone Labor Inc | Automatic gain control system |
US2520012A (en) * | 1948-01-08 | 1950-08-22 | Philco Corp | Negative bias limiter for automatic gain control circuits |
US2586193A (en) * | 1948-08-19 | 1952-02-19 | Rca Corp | Keyed automatic gain control system |
US2637773A (en) * | 1948-12-01 | 1953-05-05 | Rca Corp | Automatic gain control system |
US2819337A (en) * | 1952-06-14 | 1958-01-07 | Rca Corp | Automatic gain control circuits |
-
0
- NL NL59187D patent/NL59187C/xx active
-
1938
- 1938-03-15 US US195955A patent/US2240533A/en not_active Expired - Lifetime
-
1939
- 1939-02-16 GB GB5214/39A patent/GB525284A/en not_active Expired
- 1939-03-10 CH CH215258D patent/CH215258A/en unknown
- 1939-03-14 FR FR851588D patent/FR851588A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
NL59187C (en) | |
US2240533A (en) | 1941-05-06 |
CH215258A (en) | 1941-06-15 |
FR851588A (en) | 1940-01-11 |
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