| 摘要 |
PROBLEM TO BE SOLVED: To make a drive circuit for vibrating actuator resistant against temperature fluctuations and to improve the frequency resolution of the circuit, by outputting the delay signal pulse corresponding to a pulse selected based on delay data, which shift by each unit time to a ring oscillator in a frequency signal generating circuit. SOLUTION: When a frequency command which indicates the frequency in the one-period time of a required pulse is inputted to an arithmetic means 3, a number of frequency dividing times is set as the frequency dividing factor of a frequency dividing means 4. When the number of frequency dividing times is set, a pulse P0 is outputted from the means 4. Furthermore when a delaying means 5 outputs a delayed pulse P1 by delaying the pulse P0, the first one of the pulse P1 is outputted from the time when the first one of the pulse P0 is outputted from the means 4. When it is set that delay time is accumulated, whenever the pulse P0 is outputted from the means 4, the frequency can be set with a resolution finer than the resolution of clocks. A ring oscillator, which is a kind of VCO, controls the individual delay time by changing a power source, because its inversion element is connected in an annular state and its oscillation frequency is changed by the output signal of a low-pass filter. |
