Abstract: A power supply for a travelling-wave tube (TWT) includes a beam power supply (14) connected to the cathode and collector of the TWT, and a further power supply (20) connected to ground and to the collector for establishing the cathode-to-body voltage. A feedback cathode voltage regulator includes a transresistance arrangement (31) connected between ground and a terminal of the further power supply which, in one version, includes a cascade of a control transresistance device (32) with a plurality of further transresistance devices (234s) for reducing the voltage to which the control device is subjected. In another version, a plurality of such transresistance arrangements (A,B) are paralleled for reducing the power which any one device must handle. In a preferred embodiment, a current equalizer (240) equalizes the load carried by each of the transresistance arrangements (A,B).

Abstract: A plurality of comparators are used to compare first, second, and third input signals against a first and second predetermined signal level threshold. The outputs of the comparators are combined to ascertain the difference in signal amplitude between the first, second, and third input signals with respect to the first and second predetermined signal thresholds. If the amplitude deviation of the first, second, and third signals are within the threshold limits, a control signal adjusts the characteristics of the first and second signal channels to match the amplitude of the first and second signals to the amplitude of the third signal to make the three input signals equal. If the first, second, and third input signal deviation is without the threshold limits, the input signals are assumed correct, and no adjustment is made.

Abstract: A sync regenerator is provided which regenerates synchronizing information signals having a varying amplitude and width by comparing the sync signals in a comparator circuit to which a source of reference potential is applied. The comparator output signal of fixed amplitude is pulse width detected and the value of the detector output voltage is coupled by a feedback circuit to the reference potential source to vary the reference potential so as to maintain the width of the comparator output signal constant. The regenerated sync output signal is of constant amplitude and constant width.

Abstract: A video blanking circuit is provided which inserts a system blanking interval signal having controlled leading and trailing edges into a video signal. The blanking signal is combined with a clamped video signal in a first non-additive mixer which also provides a white clip level. The output of the first non-additive mixer is further coupled to a second non-additive mixer in which black level excursions are clipped so as to provide an output video signal having a proper system blanking interval into which synchronizing information may be added to complete the composite video waveform.

Abstract: A plurality of comparators are used to compare the red, blue and green color signals of a color television camera against a first and second predetermined signal level threshold corresponding to selected values of grey scale. The outputs of the comparators are combined to ascertain the difference in signal amplitude between the red, blue and green signals with respect to the first and second predetermined signal thresholds which represent grey. If the amplitude deviation of the red, blue and green color signals is within the threshold limits, a control signal adjusts the gamma characteristics of the blue and red color channels to match the amplitude of the red and blue color signals to the amplitude of the green color signal to correct to grey. If the red, blue and green color signal deviation is without the threshold limits, the color signal is assumed correct and no adjustment is made.

Abstract: A push-pull common emitter deflection output stage energized by a relatively low direct voltage includes zener diode drive coupling to its input circuit for reducing crossover distortion. A diode in series with a deflection winding disconnects the output stage from the winding during a portion of the retrace interval to allow the retrace pulse voltage to rise to a relatively high direct voltage supplied through a switched transistor only during the retrace interval to reduce power dissipation in the output stage. Current feedback from the deflection winding to a driver stage during trace and retrace intervals accurately determines the retrace duration.

Abstract: An electronic signal mixer is provided for combining first and second signals by additively (or differentially) combining the first and second signals to provide a first output signal. The first and second signals are further combined in a multiplier circuit to provide an output signal which is a differential (or additive) combination of the first and second signals multiplied by a coefficient determined by a control voltage applied to the multiplier. The first combined signal and the product output of the multiplier are further combined to provide a resultant signal comprised of any proportionality of the first and second signals in accordance with the value of the control voltage.