As data acquisition systems' performance continues to increase, so does the need for a test and characterization solution to have an input test signal with purity that exceeds what is currently available in state of the art instruments. This paper presents a new method for generating ultra-pure sine wave that can be used in such applications. The pure sine wave is generated by readily available DACs with distortions that could be thousands time worse than the required system purity. Readily available ADC with similar purity as the DAC is used to measure the distortions generated by the DAC. Innovative algorithm is used to iteratively remove distortions present in the generated sine wave. Simulation results verified the proposed method by generating a −140dB ultra-pure sine wave using two DACs and an ADC with −85dB THD. A test board has been designed and measurement results demonstrated that generated sine wave has the high purity that is capable of testing an ADC with −120dB THD accurately.
['Yuming Zhuang', 'Akhilesh Kesavan Unnithan', 'Arun Joseph', 'Siva Sudani', 'Benjamin Magstadt', 'Degang Chen']
Low cost ultra-pure sine wave generation with self calibration