Query: Oscilloscope

title: Terahertz Oscilloscope for Recording Time Information of Ultrashort Electron Beams.
abstract: We propose and demonstrate a terahertz (THz) oscilloscope for recording time information of an ultrashort electron beam. By injecting a laser driven THz pulse with circular polarization into a dielectric tube, the electron beam is swept helically such that the time information is uniformly encoded into the angular distribution that allows one to characterize both the temporal profile and timing jitter of an electron beam. The dynamic range of the measurement in such a configuration is significantly increased compared to deflection with a linearly polarized THz pulse. With this THz oscilloscope, nearly 50 fold longitudinal compression of a relativistic electron beam to about 15 fs (rms) is directly visualized with its arrival time determined with 3 fs accuracy. This technique bridges the gap between streaking of photoelectrons with optical lasers and deflection of relativistic electron beams with radio frequency deflectors, and should have wide applications in many ultrashort electron beam based facilities.

title: The complete optical oscilloscope
abstract: Observing ultrafast transient dynamics in optics is a challenging task. Two teams in Europe have now independently developed 'optical oscilloscopes' that can capture both amplitude and phase information of ultrafast optical signals. Their schemes yield new insights into the nonlinear physics that takes place inside optical fibres.

title: VS oscilloscope: A new tool to parameterize tree radial growth based on climate conditions
abstract: It is generally assumed in dendroecological studies that annual tree ring growth is adequately determined by a linear function of local or regional precipitation and temperature with a set of coefficients that are temporally invariant. However, various researchers have maintained that tree ring records are the result of multivariate, often nonlinear biological and physical processes. To describe critical processes linking climate variables with tree ring formation, the process based tree ring Vaganov Shashkin model (VS model) was successfully used. However, the VS model is a complex tool requiring a considerable number of model parameters that should be re estimated for each forest stand. Here we present a new visual approach of process based tree ring model parameterization (the so called VS oscilloscope) which allows the simulation of tree ring growth and can be easily used by researchers and students. The VS oscilloscope was tested on tree ring data for two species (Larix gmeliniiand Picea obovata) growing in the permafrost zone of Central Siberia. The parameterization of the VS model provided highly significant positive correlations (p 0.0001) between simulated growth curves and original tree ring chronologies for the period 1950 2009. The model outputs have shown differences in seasonal tree ring growth between species that were well supported by the field observations. To better understand seasonal tree ring growth and to verify the VS model findings, a multi year natural field study is needed, including seasonal observation of the thermo hydrological regime of the soil, duration and rate of tracheid development, as well as measurements of their anatomical features.

title: Analysis of arc welding process using Digital Storage Oscilloscope
abstract: During welding, random variations in current and voltage occur, which cannot be recorded with ordinary ammeter and voltmeter. Acquisition of voltage and current signals while welding is in progress at a very high speed using Digital Storage Oscilloscope (DSO) and subsequent analysis of the stored data can be very useful to understand the arc welding process. In the present study, welding data were acquired for two inverter and two generator power sources while welding with two different electrodes using a DSO at the sampling rate of 40,000 samples/s. This data was filtered using the Fast Fourier Transform (FFT) low pass filter and subjected to time domain and statistical analysis. Probability Density Distributions (PDDs) were used to evaluate performance of power sources and consumables. Results clearly differentiate between the arc characteristics for different power sources and consumables.

title: Petahertz optical oscilloscope
abstract: The time dependent field of an electromagnetic pulse can be measured if there is a fast enough gate. For terahertz radiation, femtosecond photoinjection of free carriers into a semiconductor in the presence of the terahertz radiation can serve as the gate1. For visible or infrared radiation, attosecond photoionization of a gas target in the presence of the optical field is a direct analogue2,3,4,5,6,7,8. Here, we show that nonlinear optical mixing9,10,11,12,13 in a medium in which attosecond pulses are being generated can also be used to measure the time dependent field of an optical pulse. The gate is the phase accumulated by the recollision electron during the subcycle time interval between ionization and recombination. We show that the instantaneous field of an unknown pulse is imprinted onto the deflection of the attosecond extreme ultraviolet pulse using an all optical set up with a bandwidth up to 1 PHz. A new laser field measurement technique is demonstrated that exploits nonlinear optical mixing in a gas in which attosecond pulses are being generated. The instantaneous field of an unknown pulse is imprinted onto the deflection of an attosecond pulse using an all optical set up with a bandwidth of up to 1 PHz.

title: An Oscilloscope Correction Method for Vector Corrected RF Measurements
abstract: The transfer characteristics of the RF front end circuitry of a real time oscilloscope (RTO) are not only frequency dependent and nonlinear with signal amplitude but also dependent on the voltage range setting of the oscilloscope. A correction table in the frequency domain is proposed to account for the additional gain and delay introduced when switching between different voltage ranges. The table was extracted from the measured data in which a continuous wave signal source was connected to the oscilloscope ports, whereas the input power, the frequency, and voltage ranges were varied. The importance of the corrections is demonstrated by its use in an RTO based two port vector corrected measurement system. Measurements from the oscilloscope based system are compared with a vector network analyzer (VNA) leading to less discrepancy in the measured S parameters of two amplifiers when using the proposed correction technique.

title: Detection capability of a pulsed Ground Penetrating Radar utilizing an oscilloscope and Radargram Fusion Approach for optimal signal quality
abstract: In scientific research pulsed radars often employ a digital oscilloscope as sampling unit. The sensitivity of an oscilloscope is determined in general by means of the number of digits of its analog to digital converter and the selected full scale vertical setting, i.e. the maximal voltage range displayed. Furthermore oversampling or averaging of the input signal may increase the effective number of digits, hence the sensitivity. Especially for Ground Penetrating Radar applications high sensitivity of the radar system is demanded since reflection amplitudes of buried objects are strongly attenuated in ground. Hence, in order to achieve high detection capability this parameter is one of the most crucial ones. In this paper we analyze the detection capability of our pulsed radar system utilizing a Rohde Schwarz RTO 1024 oscilloscope as sampling unit for Ground Penetrating Radar applications, such as detection of pipes and cables in the ground. Also effects of averaging and low noise amplification of the received signal prior to sampling are investigated by means of an appropriate laboratory setup. To underline our findings we then present real world radar measurements performed on our GPR test site, where we have buried pipes and cables of different types and materials in different depths. The results illustrate the requirement for proper choice of the settings of the oscilloscope for optimal data recording. However, as we show, displaying both strong signal contributions due to e.g. antenna cross talk and direct ground bounce reflection as well as weak reflections from objects buried deeper in ground requires opposing trends for the oscilloscope's settings. We therefore present our Radargram Fusion Approach. By means of this approach multiple radargrams recorded in parallel, each with an individual optimized setting for a certain type of contribution, can be fused in an appropriate way in order to finally achieve a single radargram which displays all contributions occurring originally at different strengths in an equalized and normalized way by means of appropriate digital signal post processing.

title: Optoelectronic time domain characterization of a 100 GHz sampling oscilloscope
abstract: We have carried out an optoelectronic measurement of the impulse response of an ultrafast sampling oscilloscope with a nominal bandwidth of 100 GHz within a time window of approximately 100 ps. Our experimental technique also considers frequency components above the cut off frequency of higher order modes of the 1.0 mm coaxial line, which is shown to be important for the specification of the impulse response of ultrafast sampling oscilloscopes. Additionally, we have measured the reflection coefficient of the sampling head induced by the mismatch of the sampling circuit and the coaxial connector which is larger than 0.5 for certain frequencies. The uncertainty analysis has been performed using the Monte Carlo method of Supplement 1 to the 'Guide to the Expression of Uncertainty in Measurement' and correlations in the estimated impulse response have been determined. Our measurements extend previous work which deals with the characterization of 70 GHz oscilloscopes and the measurement of 100 GHz oscilloscopes up to the cut off frequency of higher order modes.

title: A seamless acquisition digital storage oscilloscope with three dimensional waveform display.
abstract: In traditional digital storage oscilloscope (DSO) sampled data need to be processed after each acquisition. During data processing, the acquisition is stopped and oscilloscope is blind to the input signal. Thus, this duration is called dead time. With the rapid development of modern electronic systems, the effect of infrequent events becomes significant. To capture these occasional events in shorter time, dead time in traditional DSO that causes the loss of measured signal needs to be reduced or even eliminated. In this paper, a seamless acquisition oscilloscope without dead time is proposed. In this oscilloscope, three dimensional waveform mapping (TWM) technique, which converts sampled data to displayed waveform, is proposed. With this technique, not only the process speed is improved, but also the probability information of waveform is displayed with different brightness. Thus, a three dimensional waveform is shown to the user. To reduce processing time further, parallel TWM which processes several sampled points simultaneously, and dual port random access memory based pipelining technique which can process one sampling point in one clock period are proposed. Furthermore, two DDR3 (Double Data Rate Three Synchronous Dynamic Random Access Memory) are used for storing sampled data alternately, thus the acquisition can continue during data processing. Therefore, the dead time of DSO is eliminated. In addition, a double pulse test method is adopted to test the waveform capturing rate (WCR) of the oscilloscope and a combined pulse test method is employed to evaluate the oscilloscope's capture ability comprehensively. The experiment results show that the WCR of the designed oscilloscope is 6,250,000 wfms/s (waveforms per second) the highest value in all existing oscilloscopes. The testing results also prove that there is no dead time in our oscilloscope, thus realizing the seamless acquisition.

title: A low cost portable oscilloscope for educational platforms using a Programmable System on Chip
abstract: This paper discusses the design and implementation of a portable oscilloscope using a Programmable System on Chip (PSoC) The main aim of this paper is to highlight the use and need of a low cost system for student applications. The system was implemented using a PSoC 4 device and a Nokia 5110 LCD screen. Performance metrics were measured and compared to show tradeoffs between cost and performance.