Abstract: Apparatus for adjusting the black image current bias of a kinescope in a video signal display system includes means for developing a control signal representative of the black current bias condition of the kinescope. The control signal is developed in response to a sample of an integrated group of sensed bias representative signals developed over several horizontal line intervals which are significant in number relative to the number of horizontal line intervals associated with a vertical field interval. In the case of a color kinescope having plural electron guns, plural groups of signals respectively representative of the black current bias of each electron gun are developed. The plural signal groups exhibit a mutually time sequential relationship and are processed by a common signal processor to develop an integrated version of each of the bias representative signal groups.

Abstract: An interface circuit in a kinescope bias control system includes a transistor with a base electrode coupled to the output of a kinescope drive amplifier in a television receiver, an emitter electrode coupled to a kinescope cathode, and a collector output coupled to an output circuit which provides signals to signal processing circuits. A current related to the kinescope black current level is applied to the emitter electrode. The signal gain from the base electrode to the output circuit is significantly less than the signal gain from the emitter electrode to the output circuit. Spurious signals including noise from the output of the kinescope driver are thereby significantly attenuated at the output circuit, preventing distortion of black current representative signals provided from the output circuit.

Abstract: A side pincushion correction circuit is coupled to a horizontal resonant retrace circuit which includes a retrace capacitor and a horizontal deflection winding. The correction circuit includes an inductance and a controllable switch which is turned on during each horizontal retrace interval. A compensating circuit comprising secondary winding of a flyback transformer is coupled to the inductance and reflects the inductance onto the primary winding side in series with the deflection winding when the switch is open circuited and reflects the inductance in parallel with the deflection winding when the switch is conducting. The on-off ratio of the switch during horizontal retrace is modulated at a vertical parabolic rate to achieve side pincushion correction. The turns ratio of the flyback transformer is selected to adjust the resonant frequency and the retrace time modulation created by the correction circuit.