GB1416140A - Circuit arrangements for the non-additive mixing of electrical signals - Google Patents

Circuit arrangements for the non-additive mixing of electrical signals

Info

Publication number
GB1416140A
GB1416140A GB6081371A GB6081371A GB1416140A GB 1416140 A GB1416140 A GB 1416140A GB 6081371 A GB6081371 A GB 6081371A GB 6081371 A GB6081371 A GB 6081371A GB 1416140 A GB1416140 A GB 1416140A
Authority
GB
United Kingdom
Prior art keywords
signal
caption
mixed
input
signals
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
GB6081371A
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.)
EMI Ltd
Original Assignee
EMI Ltd
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 EMI Ltd filed Critical EMI Ltd
Priority to GB6081371A priority Critical patent/GB1416140A/en
Publication of GB1416140A publication Critical patent/GB1416140A/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
    • H04N5/222—Studio circuitry; Studio devices; Studio equipment
    • H04N5/262—Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects
    • H04N5/265—Mixing

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Processing Of Color Television Signals (AREA)

Abstract

1416140 Television EMI Ltd 28 Nov 1972 [30 Dec 1971] 60813/71 Heading H4F A video signal A at input 11, e.g. a colour signal, is non-additively mixed with a video signal B or caption signal at input 18, the composite output signal from mixer 17 comprising at any instant the larger of the two input signals, and the arrangement including a selectively operable switch 20 which when a caption signal is being mixed with signal A causes the caption signal's amplitude to be increased, e.g. doubled by multiplier 21, so that it is greater than the maximum level of signal A. This prevents the mixed signal containing chroma information instead of the required peak white caption signal. In addition the caption signal is preferably clamped 22 below the minimum level of the signal A during blanking intervals so that the negative portions of the burst signals in signal A are not removed by the caption signal, i.e. the complete burst signal from signal A is present in the mixed signal. With ganged switches positioned as shown, i.e. for a caption signal input, the inversely related (inverter 26) clamping levels of circuits 13 and 22 are determined by potential divider 25, but when the video signal A is mixed with the video signal B the switches 20 and 24 are caused to assume their V positions and the relative clamping levels of the two signals are controlled by fader 15.
GB6081371A 1971-12-30 1971-12-30 Circuit arrangements for the non-additive mixing of electrical signals Expired GB1416140A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB6081371A GB1416140A (en) 1971-12-30 1971-12-30 Circuit arrangements for the non-additive mixing of electrical signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6081371A GB1416140A (en) 1971-12-30 1971-12-30 Circuit arrangements for the non-additive mixing of electrical signals

Publications (1)

Publication Number Publication Date
GB1416140A true GB1416140A (en) 1975-12-03

Family

ID=10486131

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6081371A Expired GB1416140A (en) 1971-12-30 1971-12-30 Circuit arrangements for the non-additive mixing of electrical signals

Country Status (1)

Country Link
GB (1) GB1416140A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844418A1 (en) * 2002-09-10 2004-03-12 Siemens Vdo Automotive Car graphic control navigation image embedding process having two image sources and combining mechanism with first image providing black level on/off combining first signal under both conditions.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844418A1 (en) * 2002-09-10 2004-03-12 Siemens Vdo Automotive Car graphic control navigation image embedding process having two image sources and combining mechanism with first image providing black level on/off combining first signal under both conditions.

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees