PINCUSHION CORRECTED VERTICAL DEFLECTION CIRCUIT

• US 3,760,222 A
• Filed: 02/07/1972
• Issued: 09/18/1973
• Est. Priority Date: 05/15/1970
• Status: Expired due to Term

• Current Assignee: RCA Corporation (General Electric Company)
• Original Assignee: Lawrence Edward Smith
• Inventors: Smith, Lawrence Edward
• Primary Examiner(s): Quarforth, Carl D.
• Assistant Examiner(s): Nelson, P. A.
• Application Number:
  US05/224,191
• Time in Patent Office: 589 Days
• Field of Search: 315/13C,27TD,27GD,27R,28,29
• US Class Current: 315/371
• CPC Class Codes: H03K 4/71 with negative feedback through a capacitor, e.g. Miller-integrator

Abstract

Transistorized vertical deflection circuit employs output stage of class B, push-pull, complementary symmetry configuration with vertical yoke winding halves serially connected in output circuit. Miller integrator approach is used for sawtooth wave generation, with feedback waveform derived from yoke current sampling resistor. Discharge transistor is responsive to feedback of flyback pulses developed across serially connected yoke winding halves. Apparatus disposed between winding halves introduces modulated horizontal deflection frequency current components in winding halves for pincushion correcting purposes. One winding half of vertical deflection yoke is shunted by a capacitor of a value selected to introduce cancellation of horizontal deflection frequency components across yoke/pincushion circuitry, in order to minimize feedback of interlace-disturbing horizontal components in pincushion corrected vertical deflection circuit.

Claims

1. In a color television receiver, a vertical deflection circuit subject to introduction of a horizontal deflection frequency component for dynamic top-and-bottom pincushion correction of a displayed raster, said vertical deflection circuit including a vertical deflection winding having symmetrical halves traversed serially by a vertical deflection current;

a parallel resonant network serving as a source of said horizontal deflection frequency correction component and tuned to a frequency in the immediate vicinity of said horizontal deflection frequency, said network being interposed between said deflection winding halves for traversal by said vertical deflection current;

a pair of similarly valued resistors connected in series between respective end terminals of said deflection winding halves remote from said resonant network, the junction of said series connected resistors being connected to an intermediate point in said parallel resonant network; and

means, comprising a capacitor shunted across one of said winding halves, for providing substantial cancellation of horizontal deflection frequency voltage components between said end terminals.

2. In a color television receiver, a vertical deflection circuit subject to introduction of a horizontal deflection frequency component for dynamic top-and-bottom pincushion correction of a displayed raster, said vertical deflection circuit including a vertical deflection winding having symmetrical halves traversed serially by a vertical deflection current;

a parallel resonant network serving as a source of said horizontal deflection frequency correction component and tuned to a frequency in the immediate vicinity of said horizontal deflection frequency, said network being interposed between said deflection winding halves for traversal by said vertical deflection current;

a pair of similarly valued resistors connected in series between respective end terminals of said deflection winding halves remote from said resonant network, the junction of said series connected resistors being connected to an intermediate point in said parallel resonant network; and

a capacitor shunted across one of said winding halves, said capacitor having a capacitance value such that said capacitor presents an impedance at said horizontal deflection frequency approximately half the value of impedance presented at said horizontal deflection frequency by said one winding half.

3. In a television receiver, a vertical deflection circuit comprising the combination of:

vertical deflection wave generating means;

a deflection yoke having a pair of vertical deflection winding sections;

a vertical deflection wave amplifier having an input circuit coupled to said vertical deflection wave generating means and an output circuit in which said pair of vertical deflection winding sections are serially connected;

feedback means coupled between said output circuit and said deflection wave generating means for rendering said generating means responsive to the voltage appearing across said serially connected vertical deflection winding sections;

dynamic pincushion correcting means disposed in series with said vertical deflection winding sections for causing the flow of horizontal deflection frequency current components in said winding sections; and

means for protecting said generating means from disturbance by feedback of horizontal deflection frequency voltage components, said last-named means comprising a capacitor shunted across one of said vertical deflection winding Sections.

4. Apparatus in accordance with claim 3 wherein said capacitor has a capacitance value of such a magnitude that siaid capacitor presents an impedance at said horizontal deflection frequency approximating half the value of impedance presented at said horizontal frequency by said one vertical deflection winding section.