DE1033704B - Contrast control in a television set - Google Patents

Contrast control in a television set

Info

Publication number
DE1033704B
DE1033704B DET13645A DET0013645A DE1033704B DE 1033704 B DE1033704 B DE 1033704B DE T13645 A DET13645 A DE T13645A DE T0013645 A DET0013645 A DE T0013645A DE 1033704 B DE1033704 B DE 1033704B
Authority
DE
Germany
Prior art keywords
pulse
differentiated
contrast control
resistor
contrast
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.)
Pending
Application number
DET13645A
Other languages
German (de)
Inventor
Claus-Arno Hoeh
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.)
Metz Transformatoren & App
Original Assignee
Metz Transformatoren & App
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 Metz Transformatoren & App filed Critical Metz Transformatoren & App
Priority to DET13645A priority Critical patent/DE1033704B/en
Publication of DE1033704B publication Critical patent/DE1033704B/en
Pending 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
    • 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
    • H04N5/57—Control of contrast or brightness

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Television Receiver Circuits (AREA)

Description

Die Erfindung betrifft ein Verfahren zur Kontrastregelung bei einem Fernsehempfänger mit getasteter Verstärkungsregelung, Durch die Kontrastregelung wird bekanntlich die Amplitude des Videosignals eingestellt. Eine solche Regelung kann im Hochfrequenz- S teil durch Änderung der Gittervorspannung der Zwischenfrequenzröhren oder der Bildendröhre erfolgen. The invention relates to a method for contrast control in a television receiver with keyed Gain control, as is known, the contrast control adjusts the amplitude of the video signal. Such a control can be in the high-frequency S part by changing the grid bias Intermediate frequency tubes or the picture tube.

Bei Empfängern mit getasteter Verstärkungsregelung ist es zudem bekannt, die Vorspannung von Hoch- und Zwischenfrequenzröhren mittels Potentiometer nach der Taströhre zu ändern, was aber eine gewisse Einengung der Regelsteilheit zur Folge hat. Bekannt ist fernerhin eine Kontraständerung durch Beeinflussung der Taströhre selbst. Die Änderung der Schirmgitterspamiung einer Tastpentode z. B. beeinflußt aber auch die Regelsteilheit. Schließlich ist es bekannt, den Kontrast durch unmittelbare Beeinflussung der Verstärkung der Video-Endröhre oder durch eine veränderbare Gegenkopplung zwischen der ao Kathode und der Steuerelektrode der Bildröhre zu regeln.In receivers with keyed gain control, it is also known to adjust the bias of To change high and intermediate frequency tubes by means of a potentiometer after the probe tube, but what a results in a certain narrowing of the control steepness. Furthermore, a change in the contrast is known Influence of the probe tube itself. B. influenced but also the steepness of the rules. After all, it is known to influence the contrast directly the amplification of the video output tube or a variable negative feedback between the ao To regulate the cathode and the control electrode of the picture tube.

Beim erfindungsgemäßen Verfahren wirkt die Kontrastregelung auf die Tastschaltung, von der die Gittervorspannung für die zu regelnden Stufen abgeleitet wird. Der Taströhre, die ein ein- oder mehrgittriges Röhrensystem darstellen kann, wird in bekannter Weise über die Kathode das demodulierte Bildsignal mit Gleichspannungskomponente zugeführt. Gleichzeitig liegen normalerweise an der Anode dieser Röhre die Vergleichsimpulse aus Zeilengenerator oder Zeilentransformator. Grundsätzlich könnte als Taströhre auch eine Diode oder ein Transistor Anwendung finden.In the method according to the invention, the contrast control acts on the key circuit from which the grid bias for the stages to be controlled is derived. The tactile tube, which is a single or multi-lattice Can represent tube system, the demodulated image signal is in a known manner via the cathode supplied with DC component. At the same time usually lie at the anode of this tube the comparison pulses from the line generator or line transformer. Basically it could be used as a tactile tube a diode or a transistor can also be used.

Es ist bekannt, als Vergleichsimpulse statt der ursprünglichen Zeilenimpulse vielmehr durch deren Differentiation an i?C-Gliedern gewonnene Stromstöße großer Flankensteilheit zu verwenden. Gemäß der Erfindung wird nun durch Beeinflussung des arithmetischen Mittelwertes dieses der Anode der Taströhre zugeführten differenzierten Rücklaufimpulses die erzeugte Regelspannung und damit der Verstärkungsgrad, also der Kontrast, geändert. Dieser arithmetische Mittelwert kann verändert werden durch das Maß der Differentiation als solches und damit Variation der Impulsbreite und auch Impulshöhe des Tastimpulses oder bei fest eingestellter Differentiation des Rücklauf impulses durch Abnahme einer veränderbaren Teilamplitude des differenzierten Impulses und Zuführung zur Anode der Taströhre.It is known to use the comparison pulses instead of the original line pulses Differentiation to use current impulses of large edge steepness obtained at i? C elements. According to the invention is now the anode of the probe tube by influencing the arithmetic mean supplied differentiated return pulse the generated control voltage and thus the gain, i.e. the contrast, changed. This arithmetic mean can be changed by the Degree of differentiation as such and thus variation of the pulse width and also the pulse height of the probe pulse or with a fixed differentiation of the return pulse by taking a changeable one Partial amplitude of the differentiated pulse and feed to the anode of the probe tube.

Die Erfindung sei durch zwei Abbildungen erläutert. The invention is illustrated by two figures.

In Abb. (a) wird der Vergleichsimpuls nach Zuführung über den Kondensator 1 über einen Konden-Kontrastregelung bei einem FernsehgerätIn Fig. (A) the comparison pulse is supplied via the capacitor 1 via a condenser contrast control on a television set

Anmelder:
Transformatoren- und Apparate-FabrikApplicant:
Transformers and apparatus factory

Paul Metz,
Fürth (Bay.), Ritterstr.5Paul Metz,
Fürth (Bay.), Ritterstrasse 5

Claus-Arno Höh, Fürth (Bay.),
ist als Erfinder genannt wordenClaus-Arno Höh, Fürth (Bay.),
has been named as the inventor

sator 2 und einen veränderbaren Reihenwiderstand (Potentiometer 3) differenziert. Je nach dem arithmetischen Mittelwert (Impulsbreite und -höhe) des differenzierten1 Impulses ergibt sich am Arbeitswiderstand 5 der Taströhre 4, deren Kathode das Videosignal von der Videoröhre 6 zugeführt wird, die Höhe der Regelspannung für die Hoch- und Zwischenfrequenzstufen. Sator 2 and a variable series resistance (potentiometer 3) differentiated. Depending on the arithmetic mean value (pulse width and height) of the differentiated 1 pulse, the level of the control voltage for the high and intermediate frequency stages results at the working resistor 5 of the probe tube 4, the cathode of which is supplied with the video signal from the video tube 6.

Eine andere Anwendung des Erfindungsgedankens zeigt Abb. (b). Der Vergleichsimpuls wird über Kondensator 7 und Widerstand 8 mehr oder minder differenziert. Über den verstellbaren Kontakt 9 des als Potentiometer ausgebildeten Widerstandes 8 erfolgt der Abgriff der Tastspannung. Die Amplitude der abgegriffenen Impulsspannung bestimmt die Höhe der abgegebenen Regel spannung.Another application of the inventive concept is shown in Fig. (B). The comparison pulse is made via a capacitor 7 and resistance 8 more or less differentiated. About the adjustable contact 9 of the as Potentiometer trained resistor 8 is the tapping of the touch voltage. The amplitude of the tapped The pulse voltage determines the level of the control voltage output.

Diese Kontrastregelung hat ganz allgemein den Vorteil, daß die Regel steilheit nahezu unverändert bleibt, da auf der Gleichstromseite keine Änderung vorgenommen wird. Eine Änderung auf der Gleichstromseite wäre gleichbedeutend mit einem Eingriff in das Spannungsteilungsverhältnis. Die Lösung nach Abb. (a) hat noch einen weiteren1 Vorzug: Bei schwach einfallendem Signal an der Antenne ist es notwendig, kräftig zu verstärken, um das Bild entsprechend auszuzeichnen. Der Bedarf an Regel vorspannung ist gering. Die Impulsbreite des stark differenzierten Tastimpulses wird damit besonders klein, die Dauer der Störmöglichkeit durch Störimpulse also gleichzeitig noch geringer als sonst.This contrast control generally has the advantage that the rule slope remains almost unchanged, since no change is made on the direct current side. A change on the direct current side would be equivalent to an intervention in the voltage division ratio. The solution according to Fig. (A) has another 1 advantage: If the signal at the antenna is weak, it is necessary to amplify it strongly in order to highlight the image accordingly. The need for control preload is low. The pulse width of the strongly differentiated key pulse is thus particularly small, the duration of the possibility of interference from interference pulses is thus at the same time even shorter than usual.

Claims (3)

Patentansprüche:Patent claims: 1. Kontrastregelung bei einem Fernsehgerät mit getasteter Verstärkungsregelung, dadurch gekennzeichnet, daß der arithmetische Mittelwert des differenzierten Rücklaufimpulses, der der Anode1. Contrast control in a television set with keyed gain control, characterized in that that the arithmetic mean of the differentiated return pulse, that of the anode 809 560/156809 560/156 PII|iHIPII | iHI der zur Erzeugung der automatischen Regelspannung dienenden Taströhre (4) als Betriebsspannung zugeführt wird, veränderbar ist.the probe tube (4) used to generate the automatic control voltage as the operating voltage is supplied, is changeable. 2. Anordnung zur Kontrastregelung nach Anspruch 1, dadurch gekennzeichnet, daß mit Hilfe eines Regel Widerstandes (3) im DifFerenzierkreis {2, 3) die Differenzierung als solche geändert und damit im wesentlichen die Impulsbreite des Tastimpulses variiert wird.2. Arrangement for contrast control according to claim 1, characterized in that the differentiation as such is changed with the aid of a rule resistor (3) in the DifFerenzierkreis {2, 3) and thus essentially the pulse width of the probe pulse is varied. 3. Anordnung zur Kontrastregelung nach Anspruch 1, dadurch gekennzeichnet, daß der Rücklaufimpuls in einer Kondensator-Widerstandsschaltung (7j 8) differenziert und eine über einen verstellbaren Abgriff (9) am Widerstand (8) entnommene Teilamplitude des differenzierten Impulses der Anode der Taströhre (4) zugeführt wird.3. Arrangement for contrast control according to claim 1, characterized in that the return pulse differentiated in a capacitor-resistor circuit (7j 8) and one via a adjustable tap (9) on the resistor (8) extracted partial amplitude of the differentiated pulse the anode of the probe tube (4) is fed. In Betracht gezogene Druckschriften:
Deutsche Patentschrift Nr. 1006 460; ,
Auslegeschriften E 9438 VIII a/21 a1 (bekanntgemacht am 8. 11. 1956), N 11268 VIIIa/21ai (bekanntgemacht am 22. 11. 1956);Considered publications:
German Patent No. 1006 460; ,
Auslegeschriften E 9438 VIII a / 21 a 1 (published on November 8, 1956), N 11268 VIIIa / 21 a i (published on November 22, 1956); österreichische Patentschrift Nr. 181 882.Austrian patent specification No. 181 882. Hierzu 1 Blatt Zeichnungen1 sheet of drawings
DET13645A 1957-05-25 1957-05-25 Contrast control in a television set Pending DE1033704B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DET13645A DE1033704B (en) 1957-05-25 1957-05-25 Contrast control in a television set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DET13645A DE1033704B (en) 1957-05-25 1957-05-25 Contrast control in a television set

Publications (1)

Publication Number Publication Date
DE1033704B true DE1033704B (en) 1958-07-10

Family

ID=7547402

Family Applications (1)

Application Number Title Priority Date Filing Date
DET13645A Pending DE1033704B (en) 1957-05-25 1957-05-25 Contrast control in a television set

Country Status (1)

Country Link
DE (1) DE1033704B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1256681B (en) * 1959-06-09 1967-12-21 Fernseh Gmbh Control circuit for a television signal to automatically compensate for rapid changes in level which occur during the standard conversion of television signals with different vertical frequencies, preferably at 10 Hz difference frequency

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT181882B (en) * 1952-05-06 1955-05-10 Int Standard Electric Corp Keyed automatic gain control system
DE1006460B (en) * 1954-06-18 1957-04-18 Loewe Opta Ag Contrast regulator for television receivers
DE962975C (en) * 1953-08-18 1957-05-02 Emi Ltd TV receiver with automatic gain control
DE971393C (en) * 1954-10-08 1959-01-22 Philips Nv Circuit arrangement in a television receiver for generating a control voltage for automatic loss compensation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT181882B (en) * 1952-05-06 1955-05-10 Int Standard Electric Corp Keyed automatic gain control system
DE962975C (en) * 1953-08-18 1957-05-02 Emi Ltd TV receiver with automatic gain control
DE1006460B (en) * 1954-06-18 1957-04-18 Loewe Opta Ag Contrast regulator for television receivers
DE971393C (en) * 1954-10-08 1959-01-22 Philips Nv Circuit arrangement in a television receiver for generating a control voltage for automatic loss compensation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1256681B (en) * 1959-06-09 1967-12-21 Fernseh Gmbh Control circuit for a television signal to automatically compensate for rapid changes in level which occur during the standard conversion of television signals with different vertical frequencies, preferably at 10 Hz difference frequency

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