| 摘要 |
A high voltage generator (50) of a television receiver includes a high voltage transformer (T1) having primary (W1) and high voltage (W2) windings. The high voltage winding (W2) is coupled to an ultor terminal (52) of a picture tube via a high voltage rectifier (D3). Retrace pulses (VR) applied to the primary winding (W1) are stepped up by the high voltage winding (W2) for generating an ultor voltage (Vhv). A source of supply voltage (+24V) is coupled to a current resupply terminal (51) of the high voltage winding (W2) and produces voltage pulses (Vrs) at the resupply terminal (51) having amplitudes which vary in accordance with ultor voltage loading. An envelope detector (10) is coupled to the resupply terminal (51) for envelope detecting amplitude variations of the voltage pulses (Vrs) to develop a size control signal (Ved) which follows loading induced variations in ultor voltage (Vhv). The size control signal (Ved) is coupled to a scanning current modulator, such as a diode modulator (30), for modulating the scanning current (ih) in a manner that regulates the raster size. |
