High-speed Sampling Oscilloscope Research Articles

Accurate calculation and shaping of the voltage pulse waveform applied to a voltage-controlled magnetic random access memory cell

This paper presents procedures for calculating and shaping the voltage pulse waveform applied to a voltage-controlled magnetic random access memory (VC-MRAM) cell, which are indispensable experimental steps for studying the dynamic toggle switching of the VC-MRAM cell driven by the application of a high-speed voltage pulse. The calculation of the voltage waveform starts from the detailed characterization of each part of the pulse propagation path using a vector network analyzer. The obtained S-parameters are used to calculate the frequency response of the entire path. Next, the output waveform of the signal source is captured using a high-speed sampling oscilloscope, which is Fourier transformed, multiplied with the frequency response of the pulse propagation path, and inverse Fourier transformed to calculate the time domain voltage waveform applied to the device under test. We also present a procedure to shape the voltage waveform as desired by taking the reverse calculation process. The calculated and observed waveforms showed close agreement in both the waveform calculation and shaping.

Reconstruction of dynamical pulse trains via time-resolved multiheterodyne detection

A multiheterodyne technique is presented which can accurately measure the complex spectrum and temporally reconstruct certain dynamic pulse trains. This technique is applied to periodic pulses formed in a LiNb0₃ Mach Zehnder modulator. The spectral amplitude and phase of 20 GHz 66% return-to-zero (RZ) pulses and 10 GHz 50% RZ pulses are measured, and compared to independent measurements from a high resolution optical spectrum analyser. The temporal pulse shape and phase is reconstructed and compared to high speed sampling oscilloscope measurements. This technique is applied to sections of a large single acquisition, allowing the reconstruction of frequency and amplitude modulated pulse trains.

Time-domain multimode dispersion measurement in a higher-order-mode fiber

We present a new multimode dispersion measurement technique based on the time-of-flight method. The modal delay and group velocity dispersion of all excited modes in a few-mode fiber can be measured simultaneously by a tunable pulsed laser and a high speed sampling oscilloscope. A newly designed higher-order-mode fiber with large anomalous dispersion in the LP(02) mode has been characterized using this method, and experimental results are in good agreement with the designed dispersion values. The demonstrated technique is significantly simpler to implement than the existing frequency-domain or interferometry-based methods.

超電導デジタルエレクトロニクスの最近の進展―低消費電力型超電導ネットワークデバイスの開発の現状―

In recent years, the development of superconducting digital electronics has been making rapid progress. A variety of digital circuits based on Single-Flux Quantum (SFQ) device technology such as high-speed switching circuits for router systems and high-speed sampling oscilloscope systems have been demonstrated. These achievements have been mainly based on the NEDO project, “Development of Low-power Superconducting Network Devices”. This paper describes these recent progress and future prospects of superconducting digital electronics.

Uncertainty of oscilloscope timebase distortion estimate

We study several problems related to the characterization of the timebase in high-speed sampling oscilloscopes. First, we examine the bias of using the method of the first-order approximation to estimate the additive and time jitter noises, and present a procedure to adjust for the bias in the estimates. We then study the bias and variance of a least-squares timebase distortion estimate that uses multiple sets of waveforms. Based on simulations, a method for calculating the uncertainty of the timebase distortion estimate is proposed. We also study the effects of amplitude and phase drifts, as well as jitter error on the estimation of timebase distortion. Results are shown using simulations with parameters that are closely related to those we observe in our laboratory.

Design and performance of an inductive current probe for integration into the trace suspension assembly

A low-cost, inductive current probe designed for integration into a disk drive trace suspension assembly is described. The main consideration for this design was to use the same materials currently found in trace suspension assemblies, and thus reducing costs, while at the same time providing a drive characterization tool capable of measuring 100 ps head field rise times. The inductive current probe consists of a pair of differential copper conductors fabricated adjacent to the write driver interconnects and magnetically coupled via a Ni-Fe thin film placed on top of these conductors. The differential conductor pair is connected to a high-speed sampling oscilloscope to measure the speed of the write current pulse and thus infer the write head field rise time. Data are shown for high-speed pulses generated with rise times of less than 100 ps.

Generalized coupled interconnect transfer function and high-speed signal simulations

A new expression for the coupled interconnect system transfer function has been derived under general linear generator and uncoupled load conditions, i.e., without any restrictions in circuit load impedance. High-speed-signals on coupled interconnects have been simulated using this transfer function. The simulation uses generalized interconnect circuit model parameters in which all line parameters are frequency dependent. The validity of the interconnect circuit parameters was confirmed previously using s-parameter measurements. High-speed signal simulation using this novel interconnect transfer function has been verified with time-domain measurements using an HP54121T high-speed sampling oscilloscope. This work accurately predicts coupled interconnect circuit responses. With this transfer function, signal integrity problems of high-performance VLSI circuits can be predicted in the design stage.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High-frequency periodic time-domain waveform measurement system

A system is presented for the accurate measurement of high-frequency periodic time-domain voltage and current waveforms of a nonlinear microwave device. The measurements are performed in the time domain using a high-speed sampling oscilloscope. The results are Fourier-transformed into the frequency domain for error correction and then back into the time domain. An error-correction algorithm is presented that makes it possible to obtain accurate waveforms in spite of nonideal system components. Practical difficulties in measurement-system characterization are also discussed. An accurate circuit model for the measurement fixture is developed and its element values are determined. Measurement results are given showing the waveforms in a microwave transistor operated in the nonlinear region. The errors caused by signal processing are discussed. >

Pulsed laser caliper for noncontact dimensional measurement

A new optical device for making caliperlike noncontact dimensional measurements on macroscopic objects is described. The device called a pulsed laser caliper, consists of a picosecond pulse laser, an ultrafast detector, various optical components, and a time-interval counter or high-speed sampling oscilloscope. Basically, a dimensional measurement is made by determining the time-of-flight difference between a reference laser pulse and another pulse which reflects off both sides of an object. Accuracy and limitations of the device are discussed briefly. Experimental results using a mode-locked argon laser and a sampling oscilloscope for pulse timing gave an accuracy of 0.075 cm in dimensional measurements of five gauge blocks with lengths from 1.9 to 10.2 cm.