| 摘要 |
<p>A combined top and bottom pincushion and gullwing distortion correction circuit uses a nonlinear reactor (T1) to introduce an appropriately modulated horizontal frequency (if) and second harmonic (i2f) of the horizontal frequency component into the vertical scanning current path. The nonlinear reactor (T1) is preferably a transformer with a secondary (W1, W2) that provides a correction voltage in series with the vertical scanning current path. The transformer effectively has two series opposing primary windings (W3, W4) magnetically coupled to the secondary (W1, W2). These primaries, energized by waves at the horizontal frequency and the second harmonic frequency, alternately predominate over each other to a variable degree, and in a manner determined by the vertical scanning current (iv), for inducing corresponding voltage at the secondary winding (W1, W2). In a preferred embodiment the secondary winding is coupled to a first tuned circuit (L4, 64) that generates a horizontal rate north-south pincushion correction component voltage of the total correction voltage. The secondary winding is also coupled to a second tuned circuit (L3, C4) that generates a horizontal frequency second harmonic rate gullwing correction component voltage of the total correction voltage.</p> |
