CRT pincushion distortion corrector for AF receiver - has double resonant circuit driving vertical deflection coil

摘要

The correction circuit is for north-south pin cushion distortion in magnetic deflection CRT's. A distortion correction signal is derived from the fly-back pulse and provides a current maximum when the line sweep voltage is a maximum. The circuit is in three basic sections, a modulator (Md), a double resonance circuit (A2) directly coupled to the modulator and itself transformer coupled into the vertical deflection coil (Lv) and a series resistor (Rv) and parallel capacitor (Cv). The double resonance circuit is fed from a potentiometer (P) in parallel with an inductance (L3), the second resonant circuit using the output transformer primary as its inductor.