Патент USA US2407655код для вставки
sept. 17, 1946. R DESERNO _ Y 2,407,654- TELEVI S ION RECEIVER Filed March '29, 1940 fmfen?ar: ' ' ` Feier ßesezwo 4 Patented Sept. 17, 1946 1 2,407,654 UNITED STATES PATENT OFFICE 2,407,654 TELEVISION RECEIVER Peter Deserno, Berlin, Germany; vested in the Alien Property Custodian Application March 29, 1940, Serial No. 32.6,565 In Germany March 17, 1939 3 Claims. 1 (Cl. 178-7.3) 2 In television receivers the automatic amplitude regulation meets with diñiculties. The simple An electron tube H, Fig. l, is the last stage of the intermediate frequency amplifier of a tele vision receiver. To this tube a ñnal tube G1 is connected through a transformer T. Tube G1 expedient of forming a mean value of the high frequency energy in order to produce the regu lating voltage is not possible because the mean value changes in accordance with `the luminosity values of the picture. In the case of bright pic tures the mean value would be greater than Iwith is arranged to act as a rectifier in known man ner. The potential arising at a resistance W and a condenser K acts to control the anode cur rent of tube Gi by means of a control grid thereof, dark ones. as will be seen in Fig. 1. In the cathode lead of Transmitting arrangements are known which the tube Gi a coupling resistance A is included 10 are based on the so-called gap synchronization, which is grounded in unipolar fashion. At re that is, a synchronizing method in which the pic sistance'A a voltage arises that corresponds to ture signals increase toward positive values from the rectified frequency mixture containing pic an amplitude that corresponds to the black value ture and synchronizing signals. The curve UA of the incoming signal voltage, while the syn of this voltage is illustrated in Fig. 2. chronizing signals are extended from the black 15 A choke coil D acts to cut off all those fre value in the reverse direction toward the zero quencies which are above line frequency. At value. With these transmitting arrangements a points P, Q a voltage UPQ, Fig. 3, is effective which regulating voltage may be obtained by taking has the synchronizing impulses segregated. 'I‘he from the frequency mixture the amplitude which maximum value of this voltage hence equals the is equivalent to the black value. This amplitude 20 black Value of the incoming voltage, as will be merely depends upon the magnitude of the re understood from Fig. 3. Condenser C thus ceived high frequency energy, being independ charges to acquire a potential Uc that corre ent of the luminosity values of the picture. According to the invention, in order to pro duce the regulating voltage equivalent to the black value the synchronizing signals are ñltered out from the rectified frequency mixture, which sponds to the black value. Rectiñer G2 prevents the condenser from dis charging through resistance A. Condenser C discharges over resistance R. whenever the dark value changes. The dimensions are such that condenser and resistance shall afford a time con stant of about a second. contains the picture and synchronizing signals, by means of a choke device while the remainder of this mixture is conveyed to a condenser in 30 The regulating voltage is derived from con such manner that its potential shall rise to be denser C, as indicated by the arrowed line QC, come equal to the black value. To such end the in order to be conveyed to a control tube or sev voltage supplied to the condenser passes through a rectifier which prevents back discharge of the condenser over the feeding source, such as a cou 35 pling" resistance. The condenser is thus always charged to the maximum value of the feeding voltage. The voltage supplied to the condenser is applied to it with such ,a polarity that its po tential increases whenever the arriving voltage varies toward the black value. Thel choke device by which the synchronizing 40 eral such tubes. What is claimed is: 1. A device for regulating the amplitudes in television receivers by a voltage equivalent to the black value of the incoming signal voltage, which comprises means for rectifying a frequency mix ture containing picture and synchronizing sig nals, said means including an output resistor having a positive and a negative terminal,` a rec tilier having an anode connected to said positive signals are filtered out from the rectified fre terminal and a cathode, a storage circuit com quency mixture is dimensioned to cut off all such frequencies as are above line frequency. The 45 bination comprising a resistance and a condenser connected in parallel, connections from one end Voltage at the condenser will hence not be able of said combination to said cathode and from the to increase beyond the black value, the synchro other end of said combination to said negative nizing impulses having been segregated. terminal, and a choke device for removing the In order to enable the potential at the con denser to decrease in accordance with the black 50 synchronizing signals from said frequency mix ture, whereby the condenser is charged to a po value whenever the receiving amplitude increases, tential corresponding to said black value.. a resistance is connected in parallel with this 2. A device according to claim 1, wherein said condenser. Such resistance and condenser are choke device is adapted to cut olf all frequencies calculated to afford a time constant that accords with the duration of several picture periods, such 55 above line frequency. as a second. 3. A device according to claim 1, wherein said In the accompanying drawing, Fig. 1 is a cir resistance and condenser combination is adapt cuit diagram showing one embodiment of the ed to aüord a time constant defined by the du invention, while Figs. 2 and 3 illustrate curves ration of a number of picture periods. ` referred to in explaining the function of this em 60 bodiment. PETER DESERNO.