INTRODUCTION OF A FOREIGN CONTROL SYSTEM

摘要

A video signal image reproducing system including a video signal processing channel, a kinescope driver for supplying amplified video signals to an image reproducing kinescope, a source of potential to which signals processed by the kinescope driver are referenced, and an adjustable brightness control network which provides a range of brightness reference voltages including a given voltage corresponding to a threshold conduction condition of the kinescope driver. The brightness network is biased from a voltage source from which the signal reference potential is derived. The signal reference potential is coupled to the kinescope driver, and to the brightness network such that the given voltage is produced when the brightness control is at a mid-range setting. A comparator compares a brightness reference voltage from the brightness control with a periodic blanking level of the video signal to provide an output control voltage, which is applied to the video channel for translating the blanking level in a direction to minimize the difference between the compared signals.