Low Distortion Sinusoidal Signal Generator with Harmonics Cancellation Using Two Types of Digital Predistortion

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Keno Sato, Takayuki Nakatani, Takashi Ishida, Toshiyuki Okamoto, Tamotsu Ichikawa, Shogo Katayama, Daisuke Iimori, Misaki Takagi, Yujie Zhao, Shuhei Yamamoto, Anna Kuwana, Kentaroh Katoh, Kazumi Hatayama, Haruo Kobayashi

Published: 2023, Last Modified: 15 Jan 2026ITC 2023EveryoneRevisionsBibTeXCC BY-SA 4.0
Abstract: This paper describes two harmonics cancellation techniques using digital predistortion (DPD) for low-distortion sinusoidal signal generation with direct digital synthesizer; it is targeted for the dynamic characteristic testing of 14-bit and 16-bit 1MS/s ADCs and their testing sinusoidal wave frequencies are around 100kHz. (i) The first one is an analog-intensive DPD method for the 16-bit ADC testing. The HD2 and HD3 of the original sinusoidal signal are measured with FFT method, and then their 180-degree phase-shifted signals are generated with an auxiliary DAC and added to the original signal to cancel the HD2 and HD3. Our experiments show that −120dBc of HD2 and HD3 can be achieved. (ii) The second one is a digital-intensive DPD method for the 14-bit ADC testing. The digital data of the 180-degree phase-shifted signals of the measured HD2 and HD3 are added to the original digital data of the direct digital synthesizer. The circuit is simple, and our experiments show that −92dBc of HD2 can be achieved. Their details of analysis, simulation and experimental results are shown.