Output 2 sine wave and 2 square wave; AD9850: 0~40MHz compatible with AD9851; After the 20~30MHz frequency harmonic wave increases the waveform will be less and less clean; Square Wave: 0~1MHz; adopt low-pass filter with 70MHz so the waveform is better than SN; DA produced the benchmark pin (PIN12) leads for easy adjustment of the range of the output waveform; Reference input voltage of comparator generated by the variable resistor; 125MHz crystal oscillator modules