Time-Domain Interleaved High Sampling Rate System for Large Signal Characterization of Non-Linear Devices

Abstract — This paper proposes a high sampling rate, 4-channel Track and Hold Amplifier based time-domain measurement setup. It achieves an equivalent high sampling rate using Coherent Time Interleaved Sampling (CTIS) technique to accurately characterize high Power amplifiers driven by repetitive pulsed RF large signal. The acquired samples are the combination of non-sequential sub-sampling technique and the measurement system based on the use of Track and Hold amplifiers to avoid Intermediate Frequency (IF) aliasing and IF filtering. This principle is applied to the large signal pulsed characterization of S-band 50 W GaN amplifier. Fully calibrated acquired time-domain waveforms and power characteristics under varying load conditions are presented. To the authors knowledge the transients at the beginning and end of pulses are measured and exhibited for the first time. Index Terms — Time-domain measurements, Track and hold amplifier, virtual sampling Frequency, Non-Linear devices