Patent ID: 6034736
Filing Date: 2000-03-07
Classification: H03L,H04N

Abstract:
A digital horizontal flyback control circuit comprising:a first input for receiving a horizontal drive signal comprising a series of pulses;a second input for receiving a flyback signal comprising a series of pulses generated when a video display beam is caused to move from an end of one line of a display to a beginning of a next line of the display by a predetermined edge of a horizontal drive signal pulse, the flyback pulse being delayed with respect to the horizontal drive signal pulse by a flyback delay period;a measuring circuit coupled to the first and second inputs for measuring the flyback delay period and producing a flyback delay value at an output thereof;a subtractor circuit coupled to the output of the measuring circuit for subtracting the flyback delay value from a set horizontal position value representing a desired delay between the flyback pulse and a reference pulse and producing a subtraction value at an output thereof;a comparator coupled to the output of the subtractor circuit for comparing the subtraction value with the value of a clock counter whose count value is reset by the reference pulse and producing a set signal at an output when the subtraction value and the clock count value are the same; anda control circuit having an input coupled to the output of the comparator for generating a control signal at an output thereof for controlling the horizontal drive signal such that the horizontal drive signal pulse is generated when the set signal is received from the comparator.