Calibrated oscilloscopic system for RF time-domain characterization of non-linear devices

Abstract : This paper proposes a fully calibrated four channel high sampling rate oscilloscopic system based on the use of Track and Hold Amplifiers. The system achieves a high equivalent sampling rate (up to 1THz) using coherent interleaved sampling principle. An accurate calibration procedure allows a 10 kHz resolution over a 3 GHz bandwidth is applied. The capabilities of the system are presented and validated by characterizing a band-pass filter and an S-band 50 W GaN high power broadband amplifier under wideband CW pulsed signal excitation. S-parameters and power characteristics measurements are also presented. The fully calibrated system has the capability to give an accurate visualization of time-domain distortions of input/output voltage and current waveforms within the pulse. It also allows the determination of rising and falling transitions times of the pulse.