| 摘要 |
PURPOSE:To reduce secular change due to a capacitor by generating a satisfactory sawtooth wave with linearity. CONSTITUTION:A horizontal synchronizing signal (a) and a vertical synchronizing signal (b) are inputted to a phase locked loop(PLL) circuit 1, and a clock pulse signal (c) and a reset pulse signal (d) are obtained, then, they are inputted to a counter 2. The counter 2 inputs output (g) to a ROM 3, and the field signal (e) of the PLL circuit 1 is inputted to the least significant bit of the ROM 3. Data of sawtooth wave is written on the ROM 3, and output data (h) is outputted as a step shape sawtooth wave via a D/A converter 4. At a first field and a second field, step shape waves with different size only by one LSB can be obtained by reading out the data of the odd address of the ROM 3 at a first field and the data of the even address at a second field with the field signal (e) to be inputted to the ROM 3. |
