| 摘要 |
PURPOSE:To provide a pulse width modulator in which the ratio between 'H' level interval and 'L' level interval of output waveform varies relatively gently as compared with the variation of the set value of register for setting the 'H' level and 'L' level intervals of a pulse width modulated waveform. CONSTITUTION:The pulse width modulator comprises a reload register 8 for storing data D1 being set as an initial value of data D and loading a waveform timer 3 every time when the time of one waveform period is measured, and a circuit 10 for comparing the data DL with a modified data D2. The pulse width modulator further comprises an incrementer/decrementer 9 which functions as an incrementer if the data D2 is larger than D1 otherwise functions as a decrementer and increments or decrements the data D1 being held in the waveform timer 3 every time when a period timer 7 measures the time of one waveform period. |
