Frequency dependent gamma correction circuit - uses double superimposition to provide wide frequency range correction for TV signals

摘要

The gamma correction circuit is for TV signals, using a mixture of corrected and uncorrected signals to obtain the desired quality, and operative over a wide frequency range without the need for transit time correction in the LF region. The signal at the input (Vi) is connected to a gamma corrector circuit (2) and thence to the non-inverting input of a differential amplifier (3) operating as a superposition circuit, the inverting input being connected to the input (Vi) directly. The superimposed signals are passed to a low pass filter (4) and one input of a superposition circuit (5) for superimposition on the original input signal (Vi).