DDS Signal Generator Module Development Board The module can output two sine waves and two square waves. Frequency coverage: 040 MHz with AD9850, and 070 MHz with AD9851. After about 2030 MHz, harmonics increase and waveform cleanliness degrades. Square wave output is available up to 1 MHz. Compatibility: designed for use with AD9850 and AD9851 DDS interfaces. Improved signaltonoise ratio Equipped with a 70 MHz lowpass filter to improve the signaltonoise ratio and overall waveform quality. Adjustable amplitude and duty cycle An A pin is provided for convenient amplitude adjustment of the output waveform. The comparator reference input voltage is generated by a variable resistor, enabling different duty cycles for square waves. Crystal oscillator stability AD9850 variant uses a 125 MHz crystal oscillator for stable operation. AD9851 variant uses a 30 MHz crystal oscillator for stable and reliable performance.