±25 ppm repeatable measurement of trapezoidal pulses with 5 MHz bandwidth

Abstract

High-quality measurements of pulses are nowadays widely used in fields such as radars, pulsed lasers, electromagnetic pulse generators, and particle accelerators. Whilst literature is mainly focused on fast systems for nanosecond regime with relaxed metrological requirements, in this paper, the high-performance measurement of slower pulses in microsecond regime is faced. In particular, the experimental proof demonstration for a 15 MS/s, ±25 ppm repeatable acquisition system to characterize the flat-top of 3 µs rise-time trapezoidal pulses is given. The system exploits a 5 MHz bandwidth circuit for analogue signal processing based on the concept of flat-top removal. The requirements, as well as the conceptual and physical designs are illustrated. Simulation results aimed at assessing the circuit performance are also presented. Finally, an experimental case study on the characterization of a pulsed power supply for the klystrons modulators of the Compact Linear Collider (CLIC) under study at CERN is reported. In particular, the metrological characterization of the prototype in terms of bandwidth, repeatability, and linearity is presented.

Enhanced analogue front-end for the measurement of the high state of wide-band voltage pulses with 87 dB common-mode rejection ratio and ±0.65 ppm 1-day offset stability

“…15 For this measurement, the purpose of the front-end is to subtract the nominal DC value of the pulse's high state from the pulse (zero translation) and then amplify the result to adapt the full-scale of the acquisition board to the high state measurement. 10 The main feature of the measurement system presented in Ref. 10 was a very-low Power Spectral Density (PSD) of roughly 14 nV/…”

“…10 The main feature of the measurement system presented in Ref. 10 was a very-low Power Spectral Density (PSD) of roughly 14 nV/…”

“…• rejection of the common-mode voltage between the analogue front-end and the upstream voltage divider, 10 which could arise from the ground loop between the two different grounds, by means of another high-precision resistors network RN1 with 0.01% of relative tolerances; • complete decoupling of the voltage divider from the analogue front-end by means of two input buffers.…”

“…For this reason, an ultra-low noise acquisition system was designed and developed at CE RN. 10 It is composed by a high-voltage divider converting the initial highvoltage down to 10 V, a custom analogue front-end and the acquisition board NI-PXI 5922. This work focuses on the low-voltage section only; thus, the high-voltage divider is not discussed.…”

“…Moreover, after the proof-of principle demonstration reported in Ref. 10, a more comprehensive metrological characterization for assessing the most critical specifications of Common Mode Rejection Ratio (C M RR) 11 and temperature dependencies 12 needed to be performed. 13 In this paper, an analogue front-end with improved CMRR and thermal stability for characterizing the high states (nominally constant valued levels) of trapezoidal voltage pulses with transition durations of 3 µs is presented.…”