| 摘要 |
PURPOSE: An apparatus and a method for converting scanning is provided to adjust the horizontal size without degrading the quality of a display screen. CONSTITUTION: In an A/D(Analog/Digital) converter(6), an input video signal is digitalized by a clock pulse(53) from a VCO(Voltage Controlled Oscillator)(4) of a PLL(Phase-Locked Loop) circuit(1). The frequency of the clock pulse is fixed. In a preprocessing circuit(7), after the number of scanning lines are changed, a digital video signal is recorded in a field memory(10). A video signal is read from the field memory by a second clock pulse(63) generated in the PLL circuit. The dividing ratio of a divider(15) of the PLL circuit is varied by a control signal. By that, the frequency of the clock pulse is varied and the number of sampling in 1H section of the read video signal of the field memory is varied. Since the number of pixels in an effective video section of the recorded video signal, according as the reading part changes the number of sampling in 1H section, the ratio between 1H section and effective video section can be changed, the horizontal size can be adjusted.
|
