Raster distortion correction circuit

A television deflection apparatus, comprising:

• a source of a first switching signal at a frequency that is related to a first deflection frequency;
• a retrace resonant circuit, including a deflection winding and a first retrace capacitance;
• a source of an input supply voltage;
• a flyback transformer having a winding that is coupled to said source of input supply voltage for developing, during a retrace interval, a flyback pulse voltage in said transformer that is coupled to an ultor terminal, such that a current that is indicative of a beam current is generated in said winding, during a trace interval;
• first switching means responsive to said first switching signal and coupled to said retrace resonant circuit for generating a deflection current in said deflection winding and for developing a first retrace pulse voltage in said retrace resonant circuit, during said retrace interval of a given deflection cycle;
• second switching means responsive to a switching control signal and coupled to said winding of said transformer and to said retrace resonant circuit for decoupling said transformer winding from said retrace resonant circuit, during a controllable first portion of said first retrace pulse voltage;
• and
• means responsive to said current in said transformer winding that is generated during said trace interval for generating said switching control signal that varies during said retrace interval to vary an amplitude of said deflection current in accordance with said transformer winding trace current.

A deflection apparatus with beam positioning error correction, comprising:

• a source of a first input signal at a frequency that is related to a horizontal deflection frequency;
• a retrace resonant circuit including a deflection winding and a retrace capacitance;
• a first transistor switch responsive to said first input signal and coupled to said retrace resonant circuit for generating a horizontal deflection current in said deflection winding and a retrace pulse voltage in said retrace resonant circuit;
• a flyback resonant circuit including a supply inductance for generating a flyback pulse voltage in said supply inductance;
• a source of a second input signal at a frequency that is related to a vertical deflection frequency;
• a second transistor switch, coupled in series with said first transistor switch during a trace interval of a given cycle of said horizontal deflection current, said second transistor switch coupling said resonant circuits during a first period of said deflection cycle and decoupling said resonant circuits during a second period of a retrace interval of said deflection cycle that varies in accordance with a control signal, such that during said second period, said flyback pulse voltage is developed at a first main current conducting terminal of said second transistor switch and said retrace pulse voltage is developed at a second main current conducting terminal of said second transistor switch;
• and
• means responsive to said retrace pulse voltage and to said second input signal for generating said control signal such that said control signal is obtained from said retrace pulse voltage by time-shifting a transition edge of said retrace pulse voltage via a signal path that excludes said supply inductance.