| 摘要 |
<p>PURPOSE:To simplify the hardware by applying the hierarchical approximate system in case the sine waveform is generated over a wide range of frequency featuring a constant phase difference. CONSTITUTION:V-f converter 1 generates the rectangular wave output featuring the frequency proportional to the input voltage, and the output is counted through binary counter 2a and 2b. For ROM3a and 3b, the output level approximate to the sine wave is set previously using the value of 2a and 2b as the addresses. D/A converter 4a and 4b generates the voltage corresponding to the weighting of the output of ROM, i,e., the signal approximated to the sine wave. In case the output of ROM3a is increased by one bit to feature a specified address, reset pulse 5 is generated to reset counter 2a. In other words, counter 2b is reset when the value of counter 2a reaches a specified value. Thus, the phase difference equivalent to the difference of the value between the two counters is given to output 6a and 6b. The same result can be obtained by presetting a certain value to the counter.</p> |
