| 摘要 |
<p>A gamma correction circuit is usually employed in a TV signal transmission end so as to adjust the output of a TV camera to fit the characteristics of typical picture tube at a receiving end.</p><p>The gamma correction circuit according to the invention comprises a first buffer amplifier (32) for producing a non-gamma corrected signal (y = 1), a second buffer amplifier (33) combined with a variable impedance circuit (34) having diodes (D31, D32) for producing gamma corrected signal (y = 2.2 for example) having an exponential characteristic curve, and a double balance type adder circuit (35) in which the gamma corrected signal can be added to the non-gamma corrected signal at a desired adding ratio with keeping their signal levels coincident by adjusting gains of the both signals.</p> |
