Linearization of vertical reference ramp

Abstract

A vertical deflection ramp voltage is generated by the charge and discharge of a resistor capacitor combination. The voltage ramp is coupled to an amplifier which drives a current through a deflection coil producing a magnetic deflection field. The ramp voltage produced by the resistor capacitor combination has an inherent exponential shape which is linearized to prevent vertical linearity errors in the deflected electron beam. Linearization is achieved by multiple feedback paths which couple the amplifier output voltage and a voltage sample of the deflection coil current to the ramp forming resistor. These feedback signals are of a polarity such to establish a constant voltage across the resistor which consequently produces a constant current flow through the resistor. Hence with constant current flow in the resistor, a linear voltage ramp is produced across the capacitor and exponential deflection cramping is avoided. The voltage sample of the deflection coil current is coupled from the wiper of a potentiometer, which by other coupling produces degenerative feedback and provides control of deflection amplitude or height.

Dependencies are inferred from the claim text.