| 摘要 |
PURPOSE:To obtain a frequency with high accuracy proportional to a digital data in average as an output as the result of addition by adding digital set data representing a desired frequency to an optional initial value at a prescribed period. CONSTITUTION:A digital adder 21 adds a data theta1 to a set data (fs) and outputs an output theta2. A data storage circuit 22 holds the output theta2 at the leading edge of a pulse having a reference frequency (fc) and outputs it. As a result, the output data theta2 of the digital adder 21 is increased in the rate of (fc)X(fs) at each second and the output data theta2 is outputted as the output theta1 via the data storage circuit 22. A specific bit digit thetam of the output data theta1 is proportional to the frequency represented by the set data (fs).
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