Driver for Diode Modulated Line Oscillator
Original Publication Date: 1980-Mar-01
Included in the Prior Art Database: 2005-Feb-13
A fast low power pin-cushion correction driver circuit for a diode modulated line oscillator for a CRT (cathode ray tube) is shown in the figure. A standard line oscillator circuit 1 functions in a conventional manner to drive line deflection coil Lm of the CRT. Line-width modulation is achieved by varying the voltage Vm at node A between 0 volts and some percentage of the supply voltage Vs. A requirement of the driver circuit is its ability to source and sink peak current of typically 2 amps at the source voltage Vm and at the line repetition rate. Further, in systems where the raster skips lines or does not have the start and finish of the raster symmetrical about the center of the screen, the correction waveform derived from the CRT frame scan waveform inevitably contains high frequency components.