Accuracy and Stability of Sinusoidal Signal Generated using DDS-9910 and TCXO as Reference Clock

Stability and accuracy of the signal generator is a critical parameter for impedance analyzer to be used for measuring Quartz Crystal Microbalance. A sinusoidal signal generator for a portable and compact impedance analyzer system can be developed using a Direct Digital Synthesizer (DDS) chip. The stability and accuracy of the generated signal from the DDS mainly depended on the signal quality and the frequency of the reference clock. The experiment showed that the output quality of the generated signal from DDS AD9910 using reference clock of TCXO at 100MHz fitted well with a sinusoidal model. A small residual value between the measured signal and the sinusoidal model was found. The stability of the generated signal was good. The frequency change resolution was 1 Hz. The generated signal frequency was highly correlated with the set frequency, but having an offset value. The standard deviation of the generated signal was less than 0.5 Hz for the generated signal frequency around 10 MHz.