GB525284A - Automatic control of television receiving systems - Google Patents

Automatic control of television receiving systems

Info

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
Application number
GB5214/39A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Aerospace Inc
Original Assignee
Hazeltine Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hazeltine Corp filed Critical Hazeltine Corp
Publication of GB525284A publication Critical patent/GB525284A/en
Expired legal-status Critical Current

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
    • 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.
GB5214/39A 1938-03-15 1939-02-16 Automatic control of television receiving systems Expired GB525284A (en)

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)

* Cited by examiner, † Cited by third party
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

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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