| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously and appropriately control a control range and a resolution even in the case where a range of an oscillation frequency is wide, in an oscillator which performs digital control of range control and precise control.SOLUTION: The oscillation frequency of an oscillator is controlled by a control value, and the oscillation frequency is specified by a primary function of the control value. For the primary function, a slice and an inclination are specified by digital values and the slice and the inclination can be set. The slices and the inclinations to be set in a plurality of frequency ranges are set to be the same ratio as each other, such that a change amount of the oscillation frequency by 1LSB of precise control can be made geometrical to the frequency in the range. Therefore, it is not necessary for a DAC for control to have bits more than needed.SELECTED DRAWING: Figure 1 |
