US2197900A - Fading regulation in television receivers - Google Patents

Description

April 23, 1940. K. SCHLESINGER FADING REGULATION IN TELEVISION RECEIVERS 2 Sheets-Sheet 1 Filed July 8, 1938 I Jm'enfop: v

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April 23, 1940.

K. 'SCHLESINGER FADING REGULATION IN TELEVISION RECEIVERS Filed July 8, 1938 2 Sheets-Sheet 2 III J17 venioz== Patented Apr. 23, 1940 Zflggfiflfl STATES PATENT @Fi' ifih'.

FADING REGULATION IN TELEVISION RECEIVERS Kurt Schlesinger, Berlin, Germany, assignor, by

mesne assignments, to Loewe Radio, Inc, a corporation of New York Application July 8, 1938, Serial No. 218,164 In Germany August 30, 1937 4 Claims. (01. 1787.5)

For regulating the sensitivity of reception in nected with the deflecting element of the Braun the case of television receivers methods are em tube. plcyed which differ considerably from those According to the invention, there is included usual in the radio art. For example, it has been in the anode circuit of the end tube i the priproposed by the applicant (application Ser No. mary coil of a transformer ii in parallel or in .3

53,534) to obtain the regulatin potential necesseries to the anode resistance. To the secondsary for the fading compensation from the synary coil there is connected the generator for obchronisation signals. This method, as comtaining the regulating potential. This transpared with other methods in which the reguformer is prefera y tuned to the frequency of lating potential is obtained from the carrier frethe image change signals. The potential tapped quency, possesses the advantage that the sensiin the secondary Coil Ch y W y Of a 6 8 tivity of reception is dependent solely on the 2 a condenser 3, with which there is connected field intensity at the place of reception and is in parallel a resistance l. The time constant of proportional to this field intensity, as the synthe elements 3 and isas large as. any image chronisation signals are always of constant size point- T e transformer Should be poled that 75 during the entire transmission and accordingly the negative impulses arrive at the cathode of also vary in the same proportion as the field the valve 2. The regulating potential is tapped intensity at the place of reception. The sensiat the terminals of the resistance i and is contivity of the reception is completely independent d c e o e a p e amplifying t b l0 of th t t of t image it m tubes of the intermediate-frequency amplifier.

It has been found that, in order to obtain a Th transformer 5 n be r p d y h h r proper regulation of the sensitivity of recepquency conde s uplin tion, and accordingly a proper image, it is neces- T0 the grid 5 0f the triode 3 there is pp sary to make the sensitivity of reception den he ne hand a pr f ably j able blockpendent solely on the synchronisation signals potential 8 and on the other hand the relaxafor the image change. tion potential for the image change. This ar- The object of the present invention i a oltrangement is such and is so dimensioned that age generating device for automatically fading he blockin f h rid 5 i in r p ed nly at compensating in a television receiver comprising the image relaxa moment! e d 5 is m an amplifier for amplifying the re eiv d signals connected with the lead traversed by the image and a relaxation oscillator for generating the relaxation DOT/911171911 p y y W y Of 2 011 frame deflecting voltage. According to the ind s vention said voltage generating device is con- By means of the blocking potential 8 there nected on the one hand to the output of said can be adjusted the duration of the release of 1:3 amplifier, and on the other hand to the output the tube 2 from the blocking effect and also the of said frame relaxation oscillator so that it is extent of the regulating potential.

controlled by said amplifier and said oscillator in The arrangement according to the invention such a manner that the voltage generated by can naturally also be employed in other fashion. said device is dependent only on the amplitude of For example, it is possible to give inductively ii) the frame synchronizing signals given from the the relaxation oscillation at the grid 5 of the tube transmitter. 2. In this case a transformer is used, which is Fig. l. discloses one embodiment of my inven- Combined Dmferamy'v'vith a p h-p ll transformer t for Obtaining automatic vomme Control to give the oscillation of relaxation generator at from the frame synchronizing sigmng the deflecting elements. This transformer is -13 Fig 2 discloses anothm. embodiment of Fig tuned to the period of return to give the relaxation oscillation at the grid 5 of the said tube 2. The regulating potential is connected preferably with any of the stages of the intermediate frequency amplifier.

I claim:

The operation of the method according to the invention will be described in a possible embodiment in conjunction with the drawings.

50 The anode of the end tube i of the receiver out- 15 t i m the known fashlon Wlth 1. In a television receiver for receiving image comm gnd of t B j tube signals, line synchronizing signals and frame The synchronisation impulses pass by way o synchronizing signals a voltage generating dea filter device 6 to the relaxation oscillation genvice for t ti lly fading compensating, an Erato? W the image Change, which is conamplifier for amplifying the received signals, 55

and a relaxation oscillator for generating the frame deflecting voltage controlled by the frame synchronizing signals, said voltage generating device being connected to said amplifier and to said relaxation oscillator in such a fashion that the voltage generated by said device is dependent only on the amplitude of the frame synchronizing signals.

2. In a television receiver for receiving image signals, line synchronizing signals and frame synchronizing signals, a voltage generating device for automatically fading compensating, an amplifier for amplifying the received signals, and a relaxation oscillator for generating the frame deflecting voltage controlled by the frame synchronizing signals, said voltage generating device consisting of condenser connected in series to a grid controlled tube and shunted by a re* sistance, the grid of said tube being coupled to the output of said relaxation oscillator in such a fashion that the tube is conductive only when a frame synchronizing impulse arrives.

3. In a television receiver for receiving image signals, line synchronizing signals and frame synchronizing signals, a voltage generating device for automatically fading compensating, an amplifier for amplifying the received signals, and a relaxation oscillator for generating the frame deflecting voltage controlled by the frame synchronizing signals, said voltage generating device consisting of a condenser shunted by a resistance and connected in series to the discharge of a grid controlled tube, the anode of which being coupled to the output of said amplifier the cathode of which being connected to said condenser and to the grid of said amplifier, the grid of said tube being coupled to the output of said relaxation oscillator in such a fashion that the tube is conductive only when a frame synchronizing impulse arrives.

4. In a television receiver for receiving image signals, line synchronizing signals and frame synchronizing signals, a voltage generating device for automatically fading compensating, an amplifier for amplifying the received signals, and a relaxation oscillator for generating the frame deflecting voltage controlled by the frame synchronizing signals, said voltage generating device consisting of a condenser shunted by a resistance and connected in series to the discharge way of a grid controlled tube, the anode of which being coupled by a transformer to the output of said amplifier, the cathode of which being connected to said condenser and to the grid of said amplifier, the grid of which being biased and coupled to the output of said relaxation oscillator in such a fashion that the tube is conducted only when a frame synchronizing impulse arrives.

KURT SCI-ILESINGER.

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