Improvement of Dynamic Accuracy of a Low-Cost 10Msps 13-bit A/D Converter

摘要

After a DC-accuracy of 0.04% was obtained on a low cost 10-Msample/s (Msps) 13-bit A/D converter, the dynamic accuracy was investigated by means of the effective number of bits (ENOB), FFT analysis and the error-amplitude of the spurious data. The improvement of dynamic accuracy is made by using hardware method and software method. Experiments showed that the gain-bandwidth of the operational amplifier subtracting the high-3-bit D/A output voltage from the A/D input voltage is the key of the hardware method. Experiments showed that FFT filter smoothing is an effective software method for improvement of dynamic accuracy. However, the number of points set for FFT filter smoothing is crucial. Larger number of the FFT filtering points makes reduction of the amplitude of the smoothed data of sine wave. This makes the improvement of dynamic accuracy by FFT filter smoothing vary limited.