Abstract: In a horizontal deflection and EHT generator circuit, the supply line is connected directly to one end of the primary winding of the EHT transformer through a series switching element, and a unidirectional element connects that end of the primary winding to the supply line to enable energy recovery to the supply line through the unidirectional element during and following retrace.
Type:
Grant
Filed:
May 9, 1990
Date of Patent:
April 30, 1991
Assignee:
Microvitec plc
Inventors:
John Butterfield, Stephen Moorhouse, Stewart Marlow
Abstract: A horizontal deflection stage for a raster scan device (e.g. a television receiver or a monitor) comprises a deflection generator, a d.c. supply regulator for the deflection generator, a voltage controlled oscillator providing drive pulses to the deflection generator, a phase detecting circuit for locking the oscillator to applied horizontal synchronizing pulses, and a sweep circuit for sweeping the oscillator through a range of frequencies until it achieves phase and frequency lock with the applied horizontal synchronizing pulses. An input to the regulator serves to control the output voltage of the regulator in accordance with the frequency to which the oscillator is locked. Thus the horizontal deflection stage automatically adjusts the horizontal timebase, and the regulated voltage supply of the deflection generator, in accordance with the frequency of the applied horizontal synchronizing pulses, without any operator adjustment being required.