| 摘要 |
<p>1475609 Gamma correction circuits TOKYO SHIBAURA ELECTRIC CO Ltd 6 June 1974 [12 June 1973] 25189/74 Heading G4G A gamma correction circuit for a television system comprises an amplifier, transistors 13, 17, receiving a D.C. video signal E i at least one diode, or diode-connected transistors 21 to 23, connected to the amplifier output at one end and to the output of an emitter follower circuit, in this case a cascade of such circuits 24 to 26, at the other end, the output E 0 being taken from the collector of transistor 17. The form of the exponential function generated is determined by a control voltage E 3 on the base of transistor 26. Transistors 21 to 23 and 24 to 26 have complementary temperature variations to provide a temperature-compensated circuit. Transistor 16 and its associated components constitute a clamping circuit to provide the D.C. input signal E i . In Fig. 1, (not shown) a single transistor (1) constitutes the amplifier and across the output thereof are resistors (3, 4) in series with diodes (5,6) connected to the emitters of emitter-follower transistors (7, 8) each having a respective control signal (E 1 , E2) connected to its base.</p> |
