the design circuit is shown in figure 1. [Analysis ][ Analysis ][ Analysis ]-The control terminal of the waveform I I control the output of the waveform and connect the phase I I﹣ to the indicator light on the POI I. The signal data is output by the POI I, and finally by the low speed D /A、 amplifier circuit and the filter circuit. frequency regulation signal is input by the p2i, and the frequency of the output waveform is changed by changing the corresponding delay subroutine, and the phase regulation signal is input by the p2i. amplitude of the signal is achieved by changing the sliding rheostat connected to the D /A and changing the reference voltage of the D /A.