PARABOLIC CORRECTION SIGNAL AMPLITUDE CONTROL LOOP

摘要

A DEFLECTION WAVEFORM CORRECTION SIGNAL GENERATOR COMPRISES A MULTIPLYING CIRCUIT FOR GENERATING A PINCUSHION CORRECTION SIGNAL. A HORIZONTAL FREQUENCY RAMP IS GENERATED (Q 1, Q2, Q3) BY A CLIPPED RETRACE PULSE. THE RAMP GENERATOR HAS AN OUTPUT COUPLED TO AN INTEGRATING CIRCUIT FOR GENERATING A PARABOLIC SHAPED SIGNAL (P). THE RAMP GENERATOR AND RAMP INTEGRATOR ARE RESET AT A HORIZONTAL RATE BY RESET PULSES OF DIFFERING DURATION. THE DIFFERENT DURATION OF RESET PULSES RESULTS IN THE PARABOLIC SIGNAL HAVING REGIONS OF NON-PARABOLIC SHAPE. THE PARABOLIC SHAPED SIGNAL IS COUPLED TO AN INPUT OF THE MULTIPLYING CIRCUIT. A CONTROL CIRCUIT IS COUPLED TO THE PARABOLIC SHAPED SIGNAL (P) FOR MAINTAINING A PEAK AMPLITUDE THEREOF BY CONTROLLABLE COUPLING TO THE RAMP GENERATOR. A CONTROL LOOP IS COUPLED TO THE INTEGRATOR (VI) FOR CONTROLLING AN INTEGRATOR INPUT BIAS CURRENT TO GENERATE THE PARABOLIC SHAPED SIGNAL AT A PREDETERMINED TIME INTERVAL.FIG. 2