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An extremely low-frequency (ELF) magnetomechanical antenna with the size of one-millionth wavelength based on a three-phase induction motor is reported, whose working frequency is no longer limited by the resonant wavelength. The rotating three-phase induction motor with nonmagnetic material shell is just equivalent to a rotating magnetic dipole with 1.5 times magnetic dipole moment. It can transmit the modulated electromagnetic (EM) signal by modulating the rotating speed of the motor. A near-field ELF EM signal transmission experiment system is constructed based on the magnetomechanical antenna with $\Phi 10$ cm $\times50$ cm size, and the transmitted EM signals were received by a 200-turn coil, which is 10–200 m far away from the transmitter. The EM signal frequency is almost the same as the rotating speed of the motor, and it varies with the rotating speed too. With arbitrary waveform generator and variable-frequency drive (VFD) modulating the rotating speed of the motor, a near-field ELF transmitter with modulating EM signal is built, and the sawtooth wave (STW)-modulated EM signal was transmitted and received clearly during 10–200 m. The square wave (SW)-modulated EM signal was communicated too. The proposed magnetomechanical antenna has a compact size and is very suitable for ELF remote wireless communication.

International audience; The design and realization of a reconfigurable antenna array operating in the 3.4-3.8 GHz band is presented. Array synthesis methods are developed to reduce the power consumption and are experimentally validated by measurements. The array is composed of 16 dual-polarized dipoles whose excitations are provided by a baseband arbitrary waveform generator. The array is able to radiate simultaneously two or more focused beams in one plane over a scanning range of ±45°, these beams can be reconfigured at will. To achieve these radiation pattern requirements while reducing as much as possible the array power consumption, specific antenna array synthesis tools are developed. In particular, the way to synthesize two sparse arrays at two frequencies having common switched-off antennas is proposed and described. This strategy, together with the synthesis of uniform amplitude excitations, enables to harness the consumption characteristics of power amplifiers. This energy-efficient synthesis means that two mobile operators can share the same antenna array. Several representative measurement results of the array prototype validate the radiation performances and experimentally demonstrate the achieved reduction of power consumption.

We propose a photonic scheme to generate binary phase-coded microwave pulses and dual-chirp microwave waveforms without baseband-modulated signals (background noise) based on a dual-polarization dual-drive Mach-Zehnder modulator (DP-DDMZM) which contains x-DDMZM and y-DDMZM at two different polarization states. A radio frequency (RF) signal from a microwave source is transferred into two differential RF signals and employed into one arm of x-DDMZM and one arm of y-DDMZM, while a baseband signal from an arbitrary waveform generator is divided by an electronic coupler and then driven into the two other arms of DP-DDMZM. By adjusting the phase differences between the x-DDMZM and the y-DDMZM, binary phase-coded pulses and dual-chirp signals without baseband-modulated signals are generated. The proposed scheme can eliminate the interference caused by baseband-modulated signals, and satisfy different radar applications for different frequency bands. Experimental results show that phase-coded signals at 15 GHz with the bit rates of 1 Gb/s and 2 Gb/s and dual-chirp signals at 10 GHz and 15 GHz with the time durations of 0.5 μs are successfully generated. The reported scheme is well analyzed in theory and verified by experiment.

This article evaluates time-domain techniques for the applications of ultrawideband (UWB) chipless radio frequency identification (RFID) readers. In UWB time-domain readers, the chipless RFID tag response to a UWB pulse excitation is simultaneously measured in time domain and then the frequency-domain signature of the tag is calculated by a time-to-frequency conversion method such as fast Fourier transform. A 32-bit UWB chipless RFID tag is designed and three time-domain readers based on impulse radio UWB, chirped-pulse Fourier transform microwave (CP-FTMW), and dual-comb techniques are analyzed and implemented by using microwave equipment including arbitrary waveform generator, network analyzer, and high-speed oscilloscope. It is demonstrated that CP-FTMW reader is a fast, accurate with high signal-to-noise ratio, and high-frequency resolution time-domain technique. Dual-comb reader is slower, however, it offers a viable solution for a low cost and potentially miniaturized and portable chipless RFID readers.

We report programmable control of pulses from a quantum cascade laser. A programmable arbitrary waveform generator is used to control the emission of the lasers by gain-switching. Quantum cascade lasers with both multi-mode and single-mode emission are studied. Laser emission is coherently detected using a phase resolved injection seeding technique based on time domain spectroscopy. For the single mode laser, pulse widths of 500–4000 ps are demonstrated, with time-bandwidth products remaining close to, or below, unity for all pulse widths. Additionally, sequences of two pulses are demonstrated, where the pulse widths, delay, and amplitude of each of the pulses are programmed electronically. A range of pulse parameters are explored. This approach allows for the generation of arbitrary terahertz pulse sequences, which will enable coherent multidimensional spec-troscopy and applications requiring optimized pulse shapes.

This paper reports the development of a highly efficient, flexible hardware platform, which is suitable for the control of spin-based quantum systems including quantum computation and quantum metrology. A two-channel arbitrary waveform generator (AWG), an eight-channel pulse/sequence generator, a two-channel analog-to-digital converter (ADC), and a two-channel high-speed time-to-digital converter (TDC) are fully integrated on a printed circuit board (PCB). The AWG has a 1-GSa/s sampling rate and a 16-bit amplitude resolution. The pulse/sequence generator can continuously output pulse/sequence signals with a 50-ps time resolution and a dynamic range from 5 ns to 2 s. The ADC provides a 1-GSa/s sampling rate and a 12-bit amplitude resolution for analog signal acquisition. The TDC provides a 6-ps time resolution and a maximum sampling frequency of 125 MHz. All these modules are realized utilizing a field-programmable gate array (FPGA). Customized data calculation modules are also implemented with the FPGA logic. The hardware was tested and implemented in a pulsed electron spin resonance (ESR) spectrometer and an optically detected magnetic resonance (ODMR) spectrometer.

Scanning acoustic microscopy (SAM) finds use across many disciplines, e.g., biology, industrial quality control, and materials science, thanks to its unique ability to quantify mechanical sample properties combined with its high resolution. However, such imaging is often slow, especially if averaging is necessary. We present a Coded Excitation Scanning Acoustic Microscope (CESAM) that employs coded signals and show that it produces images of higher signal-to-noise ratios (SNRs) than the classical SAM in a comparable measurement time. The CESAM employs coded signals instead of the short bursts used in traditional SAMs, and we employ both linear and non-linear frequency modulation. Our results show that compared to the SAM approach, this modulation increases the SNR by 16.3 dB (from 39.9 to 56.2 dB) and reduces the echo duration by 26.7% when we employ a linear chirp to the transducer with a nominal bandwidth of 130-370 MHz. Driving the transducer with a broader bandwidth signal using non-linear chirps (100-450 MHz), we obtained a SNR increase of 10.3 dB and a reduced echo duration of 70.5%. The shorter echo duration increases z-resolution, whereas the lateral resolution remains limited by the wavelength. Finally, we show that by using these coded signals, one can obtain enhanced image quality relative to the standard actuation of the same measurement time. Our results have potential to invigorate the field of acoustic microscopy, especially with samples where the enhanced SNR and/or contrast-to-noise ratio is crucial for image quality.

An electron paramagnetic resonance (EPR) imaging system has been custom built for use in pre-clinical and, potentially, clinical studies. Commercial standalone modules have been used in the design that are MATLAB-controlled. The imaging system combines digital and analog technologies. It was designed to achieve maximum flexibility and versatility and to perform standard and novel user-defined experiments. This design goal is achieved by frequency mixing of an arbitrary waveform generator (AWG) output at the intermediate frequency (IF) with a constant source frequency (SF). Low noise SF at 250, 750, and 1000 MHz are available in the system. A wide range of frequencies from near-baseband to L-band can be generated as a result. Two-stage downconversion at the signal detection side is implemented that enables multi-frequency EPR capability. In the first stage, the signal frequency is converted to IF. A novel AWG-enabled digital auto-frequency control method that operates at IF is described that is used for automatic resonator tuning. Quadrature baseband EPR signal is generated in the second downconversion step. The semi-digital approach of mixing low-noise frequency sources with an AWG permits generation of arbitrary excitation patterns that include but are not limited to frequency sweeps for resonator tuning and matching, continuous-wave, and pulse sequences. Presented in this paper is the demonstration of rapid scan (RS) EPR imaging implemented at 800 MHz. Generation of stable magnetic scan waveforms is critical for the RS method. A digital automatic scan control (DASC) system was developed for sinusoidal magnetic field scans. DASC permits tight control of both amplitude and phase of the scans. A surface loop resonator was developed using 3D printing technology. RS EPR imaging system was validated using sample phantoms. In vivo imaging of a breast cancer mouse model is demonstrated.

The reflectometry on Experimental Advanced Superconducting Tokamak (EAST) is undergoing an upgrade for more comprehensive measurement of plasma density profile and fluctuation. The Data Acquisition and Control System (DACS) has been redeveloped to satisfy the requirements of the upgraded reflectometry. The profile reflectometry works in 30-110 GHz (X-mode) and 40-90GHz (O-mode), when the fluctuation reflectometry operates at 20 fixed frequency points in 50-110GHz (X-mode) and 20-60GHz (O-mode). The PXIe-based DACS includes two 8-channel 14-bit 250MSPS digitizers and ten 8-channel 12-bit 60MSPS digitizers. A self-developed 5-channel 250MSPS arbiter waveform generator (AWG) is used to control voltage control oscillators for frequency sweeping. A trigger and clock manger and a timing module receive the trigger and clock signal from central controller and synchronize all the digitizers and the AWG. The total data rate from digitizers is 2515 MB/S. The Data from digitizers is streamed to a disk array (RAID 0) with data throughput capacity of 3000 MB/S. Meanwhile, selected data is transported to a FPGA based real-time data processing module, which utilize a pre-trained neural network to calculate the plasma density profile. Now the new reflectometry is being installed on EAST, and its performance will be tested in experimental campaign after 2018., 21st IEEE Real Time Conference

Due to the extensive applications of power electronic devices in power grids, many insulation components will be stressed by high voltage PWM, multilevel or even more complex waveforms. In this paper, a high voltage generator able to produce various waveforms is developed. The generator is based on cascade connected multilevel modular converter (MMC) topology, including 20 half bridge MMC cells with the capability of 21 output voltage levels. Half of the series-connected MMC cells are charged positively, while the other half are charged negatively. Each positive and negative half bridge MMC cell is connected alternately to optimize the insulation design. The power supply of the driving circuit for each MMC cell is provided by an individual fly-back converter fed by the cell capacitor to realize a compact design. On the basis of simulations, a multilevel arbitrary waveform generator prototype was constructed, with the maximum peak-to-peak voltage of ∼ 28 kV. A capacitor switching strategy is utilized to solve the voltage-imbalance problem resulted from the difference of the element parameters and other reasons. Finally, it was tested on a typical insulation with a simulated defect.

The arbitrary waveform generator is now commonly used to generate waveforms in many fields. The Nyquist sampling theorem only provides an open interval for the sampling rate selection, but how to determine a specific sampling rate within this open interval has not been discussed. In practice, the sample rate conversion is adopted to convert the arbitrarily selected sample rate to a safe one which keeps the mirror frequency out of a fixed passband of an anti-aliasing filter in an arbitrary waveform generator whose sample rate is variable. To select a safe sample rate with low computational cost and memory requirements for conversion, an algorithm, with fractional sample rate conversion in mind, is proposed in this paper to guarantee the safety of the target sample rate and the bound of resource cost. The experimental results show that not only the computational cost and memory requirements of sampling rate conversion but also the frequency stability and harmonics of the generated signal in the proposed algorithm overcome the method that arbitrary converts the sampling rate to a fixed maximum one.

This paper provides a comprehensive numerical and experimental analysis of 5G end-to-end systems resorting to the use of key features provided by MATLAB’s 5G toolbox. In this work, a 5G carrier fully complying with 3GPP requirements is generated and AWGN noise is added at baseband reception to study the impact of the different modulation formats on the symbol error rate (SER) and error vector magnitude (EVM). The developed simulator based on MATLAB’s 5G toolbox was then modified to incorporate the functionality of carrier aggregation. Finally, the signal generated with the simulator was loaded into an Arbitrary Waveform Generator (AWG) and propagated to an oscilloscope, first using a back-to-back electrical configuration and then using an optical link. The experimental 5G signal was received and processed by the developed MATLAB simulator, and then validated by direct comparison against theoretical and simulation results. The obtained results show that the developed end-to-end simulator is a powerful tool for the numerical and experimental analysis of high-capacity 5G transmission systems, enabling the embedded monitoring of SER and EVM.

We experimentally demonstrate a high-speed lateral PIN junction configuration germanium photodetector (Ge-PD) with 4-directional light input. The typical internal responsivity is about 1.23 A/W at 1550 nm with 98% quantum efficiency and dark current 4 nA at 1V reverse-bias voltage. The equivalent circuit model and theoretical 3-dB opto-electrical (OE) bandwidth of Ge-PD are extracted and calculated, respectively. Compared to the conventional lateral PIN Ge-PD with 1-directional light input, our proposed device features uniform optical field distribution in the absorption region, which will be benefit to realize high-power and high-speed operation. In particular, in the condition of 0.8 mA photocurrent, the measured 3-dB OE bandwidth is about 17 GHz at bias voltage of -8 V which is well matched to the theoretical estimated bandwidth. With additional digital pre-compensations provided by the Keysight arbitrary waveform generator (AWG), the root raised cosine (RRC) filter and roll-off factor of 0.65 are employed at transmitter (TX) side without utilizing any offline digital signal processing (DSP) at receiver (RX) side. The 50 Gbit/s, 60 Gbit/s, 70 Gbit/s, and 80 Gbit/s non-return-to-zero (NRZ), and 60 Gbit/s, 70 Gbit/s, 80 Gbit/s, and 90 Gbit/s four-level pulse amplitude modulation (PAM-4) clear opening of eye diagrams are realized. In order to verify the high-power handling performance in high-speed data transmission, we also investigate the 20 Gbit/s NRZ eye diagram variations with the increasing of photocurrent.

In this paper, we propose an X-band photonic-based pulsed radar architecture with a high range resolution. The proposed architecture is operated as a pulsed radar by adding a Mach-Zehnder modulator (MZM) operating as an optical switch to a transmitter of a conventional photonic-based frequency-modulated continuous wave (FMCW) radar. In addition, a balanced photodetector (BPD) is employed to enhance the amplitude of the received signal and remove common-mode noise. A proposed photonic-based pulsed radar prototype is implemented to operate at a center frequency of 10 GHz, a bandwidth of 640 MHz, and a pulse repetition frequency (PRF) of 1 kHz considering the performances of an arbitrary waveform generator (AWG). The implemented prototype is verified through an indoor experiment. As a result, the positions of targets are detected in real-time with 1.6% error rates of a range accuracy and obtained the range resolution of 0.26 m.

9 pags., 7 figs., Dual frequency comb (DFC) spectroscopy using electro-optic comb generators stands out for its flexibility, easy implementation, and low cost. Typically, two combs with different line spacing are generated from a common laser using independent electro-optic comb generators. This approach minimizes the impact of laser phase noise; however, the distinct paths followed by the two combs ultimately limit the attainable signal-to-noise ratio and long-term stability of the system. In this work, a common-path DFC is generated using a single modulator driven by an arbitrary waveform generator, thus enabling a remarkable increase of the system stability (up to 0.8 s of integration time) while maintaining high flexibility. The proposed technique is experimentally validated by implementing a dual frequency comb with 3000 lines, covering an optical bandwidth of 4.5 GHz, and demonstrating an optical-to-radiofrequency compression factor of 7500. Our system is able to measure extremely narrowband optical features (in the MHz range) with an accuracy only limited by the master laser stability., MAS acknowledges AC3E Basal Project FB0008 and thanks “Becas Iberoamérica Santander Universidades Convocatoria 2018” for supporting his research stay at Universidad de Alcalá, Spain

On the basis of integrated radio-photonic technology, the possibility of constructing a high-frequency generator of an arbitrary waveform in a wide frequency range is shown.

International audience; A superheterodyne transmission scheme is adopted and analyzed in a 300 GHz wireless point-to-point link. This was realized using two different intermediate frequency (IF) systems. The first uses fast digital synthesis which provides an IF signal centered around a carrier frequency of 10 GHz. The second involves the usage of commercially available mixers, which work as direct up- and down-converters, to generate the IF input and output. The radio frequency components are based on millimeterwave monolithic integrated circuits at a center frequency of 300 GHz. Transmission experiments over distances up to 10 m are carried out. Data rates of up to 60 Gbps using the first IF option and up to 24 Gbps using the second IF option are achieved. Modulation formats up to 32QAM are successfully transmitted. The linearity of this link and of its components is analyzed in detail. Two local oscillators (LOs), a photonics-based source and a commercially available electronic source are employed and compared. This work validates the concept of superheterodyne architecture for integration in a beyond-5G network, supplying important guidelines that have to be taken into account in the design steps of a future wireless system.

This article describes the realization of a novel approach to short pulse (∼1 ns) reflectometry (SPR) recently implemented in the tokamak configuration variable tokamak. Taking advantage of a fast arbitrary waveform generator and vector-network-analyzer extension modules, the design offers flexibility regarding pulse output frequency, duration, and repetition rate. Such flexibility allows the instrument to overcome traditional SPR spatial sampling limitations while reducing hardware complexity. In order to measure the group-delay of nanosecond-scale pulses, both traditional analog and novel digital sampling techniques have been explored. A group-delay range resolution of 17 ps (2.6 mm) in average over the V-band has been achieved with both timing techniques against a waveguide mirror featuring 10 dB power fluctuations. Direct pulse sampling during L-mode plasmas shows that reflected pulse widths increase only by 4% in average. However, pulse width dispersion does occur in L-mode plasmas and leads to an increase in the group-delay uncertainty up to 40 ps (6 mm). Raw histograms of group-delay data show interesting qualitative changes from the L mode to the H-mode. Frequency spectra of group-delay data allow the identification of macroscopic density fluctuations as well as edge quasicoherent modes during edge-localized mode-free H-modes. Finally, fast changes to the density profile have been measured with microsecond time resolution and subcentimeter spatial resolution in both O and X-mode polarizations.

Biomedical applications often require high-performance power supplies for diagnosis and treatment systems. In particular, modern electroporation techniques for cancer treatment require high-voltage generators with versatile waveform generation. In this context, sinusoidal waveform generation has been recently identified as beneficial for electrochemotherapy cancer treatments. This paper proposes the design of a high-voltage high-frequency arbitrary waveform generator taking advantage of Gallium Nitride (GaN) devices. The proposed converter has been designed and implemented, achieving a 1-MHz 2000-V output voltage. It has been electrically tested and applied to electrochemotherapy treatments in mice, demonstrating the feasibility of this proposal. This work was supported in part by the Spanish Ministerio de economía y competitividad (MINECO) and Agencia Española de Investigación (AEI) under Project TEC2016-78358-R, in part by the Spanish Ministerio de Ciencia e Innovación (MICINN) under Project PIN2019, in part by the EU through the Fondo Europeo de Desarrollo Regional (FEDER) Program, in part by the Diputación General de Aragón-Fondo Social Europeo (DGA-FSE), and in part by the DGA under Project LMP106-18.

In many electromagnetic (EM) methods – such as magnetotelluric, spectral-induced polarization (SIP), time-domain-induced polarization (TDIP), and controlled-source audio magnetotelluric (CSAMT) methods – it is important to evaluate and test the EM receivers during their development stage. To assess the performance of the developed EM receivers, controlled synthetic data that simulate the observed signals in different modes are required. In CSAMT and SIP mode testing, the waveform generator should use the GPS time as the reference for repeating schedule. Based on our testing, the frequency range, frequency precision, and time synchronization of the currently available function waveform generators on the market are deficient. This paper presents a multifunction waveform generator with three waveforms: (1) a wideband, low-noise electromagnetic field signal to be used for magnetotelluric, audio-magnetotelluric, and long-period magnetotelluric studies; (2) a repeating frequency sweep square waveform for CSAMT and SIP studies; and (3) a positive-zero–negative-zero signal that contains primary and secondary fields for TDIP studies. In this paper, we provide the principles of the above three waveforms along with a hardware design for the generator. Furthermore, testing of the EM receiver was conducted with the waveform generator, and the results of the experiment were compared with those calculated from the simulation and theory in the frequency band of interest.

This paper demonstrates a phase switching algorithm for Interpolating Digital-to-Analog Converter (DAC) based Arbitrary Waveform Generator (AWG) that resides in Automated Test Equipment (ATE) to test semiconductor devices. This confirms a previous exercise that was made by experiment with different Intermodulation Distortion (IMD) suppression techniques and starting phase shifts to suppress IMD tones of the AWG with the interpolating DAC. We show that the poor performance of the AWG can be improved by using the phase switching algorithm over the installed base of a company’s tester platform. It is also shown that the IMD performance of AWGs across a company’s tester installed base can be equalized, and how it can be achieved using the phase switching technique. We describe how the IMD specifications of the instrument are much worse than those actually measured, and by using phase switching, better performance can be achieved than what would be possible under normal conditions. We present how this technique allows the use of a low-cost tester resource to test IMD products of such as communication application ADCs with a higher dynamic range than what was previously possible.

This paper describes the implementation of LabVIEW software to control instruments and acquire data from a piezoelectric energy harvesting test station which is based on a cantilever structure. The experiment is run in the Clean Energy Laboratory on the Ambient Energy Harvester Test Station. A digital multimeter, a programmable resistance selector, an arbitrary waveform generator, a shaker table, an accelerometer and a laser displacement sensor are used to control and acquire data in terms of harvested energy as a function of vibration frequency and load resistance. LabVIEW software is used to control the test station which makes near real-time data measurements, displays waveforms on a PC screen, and stores data for later analysis. Acquired waveforms are presented in terms of frequency versus voltage of the vibrating cantilever at preselected ranges of load resistances in terms of either AC or DC voltages. The vibration of the cantilever beam is measured with an accelerometer and beam movement is measured with a laser displacement meter. Test results are stored in a comma separated variable text file which can be imported into any data analysis software package. All experiments are performed on an isolated optical bench to avoid interference from mechanical noise that may exist in the surrounding environment. The system provides an integrated approach to characterize key performance indicators for energy harvesting materials and devices.

Background Ultrasound transient elastography technology has found its place in elastography because it is safe and easy to operate. However, it’s application in deep tissue is limited. The aim of this study is to design an ultrasound transient elastography system with coded excitation to obtain greater detection depth. Methods The ultrasound transient elastography system requires tissue vibration to be strictly synchronous with ultrasound detection. Therefore, an ultrasound transient elastography system with coded excitation was designed. A central component of this transient elastography system was an arbitrary waveform generator with multi-channel signals output function. This arbitrary waveform generator was used to produce the tissue vibration signal, the ultrasound detection signal and the synchronous triggering signal of the radio frequency data acquisition system. The arbitrary waveform generator can produce different forms of vibration waveform to induce different shear wave propagation in the tissue. Moreover, it can achieve either traditional pulse-echo detection or a phase-modulated or a frequency-modulated coded excitation. A 7-chip Barker code and traditional pulse-echo detection were programmed on the designed ultrasound transient elastography system to detect the shear wave in the phantom excited by the mechanical vibrator. Then an elasticity QA phantom and sixteen in vitro rat livers were used for performance evaluation of the two detection pulses. Results The elasticity QA phantom’s results show that our system is effective, and the rat liver results show the detection depth can be increased more than 1 cm. In addition, the SNR (signal-to-noise ratio) is increased by 15 dB using the 7–chip Barker coded excitation. Conclusions Applying 7-chip Barker coded excitation technique to the ultrasound transient elastography can increase the detection depth and SNR. Using coded excitation technology to assess the human liver, especially in obese patients, may be a good choice.

Dynamic Brillouin optical fiber sensors based on fast scanning of Brillouin gain spectrum (BGS) are one of the most promising techniques to measure dynamic strains, where an ~11-GHz bandwidth arbitrary waveform generator (AWG) or a vector microwave generator is essential for frequency agility. A dynamic Brillouin optical fiber sensor based on dual-modulation is proposed here, which aims to realize dynamic sensing via a low-bandwidth AWG. In this protocol, the scanning of BGS is implemented by the combination of a single-frequency modulation and a frequency-agility modulation. The frequency of the single-frequency modulation is slightly lower than the Brillouin frequency shift of the fiber under test so that the tuning range of the frequency-agility modulation is required to cover only several-hundred MHz for the scanning of the BGS, which significantly reduces the bandwidth requirement for the AWG. In experiment, an 11.8-Hz strain is measured with a 30-m fiber, where the spatial resolution and the sampling rate are 1 m and 200 Hz, respectively. Furthermore, by tracking the damping vibration of the optical fiber, its resonant frequency is measured with a sampling rate of 100 Hz.

In this paper, a systematic and statistical calibration technique was implemented to calibrate a high-speed signal converting system containing multiple digital-to-analog converters (DACs). The systematic error (especially the imbalance between DACs) in the current combining network of the multi-DAC system was modeled and corrected by calculating the path coefficients for individual DACs with wideband reference signals. Furthermore, by applying a Kalman filter to suppress noise from quantization and clock jitter, accurate coefficients with minimum noise were identified. For correcting an arbitrary waveform generator with two DACs, a co-simulation platform was implemented to estimate the system degradation and its corrected performance. Simulation results showed that after correction with 4.8 Gbps QAM signal, the signal-to-noise-ratio improved by approximately 4.5 dB and the error-vector-magnitude improved from 4.1% to 1.12% over 0.96 GHz bandwidth.

High-performance optical pulse shaping is paramount to photonics and laser applications for which high-precision optical waveforms must be generated. We investigate the design and performance of a time-multiplexed pulse-shaping (TMPS) system in which optical waveforms from a single pulse-shaping unit are demultiplexed and retimed before being sent to different optical systems. This architecture has the advantages of low cost and low relative jitter between optical waveforms because a single pulse-shaping system, e.g., a high-performance arbitrary waveform generator driving a Mach–Zehnder modulator, generates all the waveforms. We demonstrate an eight-channel TMPS system based on a 1 × 8 LiNbO3 demultiplexer composed of four stages of 1 × 2 Δ β phase-reversal switches. It is shown that optimal demultiplexing, i.e., low insertion loss and high extinction ratio between channels, requires optimization in dynamic operation because of the slow component of the switches’ response. We demonstrate losses lower than 5 dB, extinction ratios of the order of 70 dB for a four-channel system and 50 dB for an eight-channel system, and jitter added by the demultiplexer smaller than 0.1 ps.

In this paper, we describe how a phase switching technique is used to control the harmonic contents of a generated sinusoidal signal using digital signal processing techniques. We will describe how this technique equalizes the harmonic performance of arbitrary waveform generators installed in a large scale integration test system, allowing extended performance testing of the total harmonic distortion of an analog-to-digital converter that ordinarily would be possible only using more advanced test equipment. Once a device has been characterized and correlated to the bench, a test engineer is required to release the product into production. One of the major issues surrounding this exercise is the difference in the obtained results between testers of the same manufacture for parameters sensitive to harmonics, noise, and spurious components such as total harmonic distortion. By using the techniques developed in this paper, the user will be able to deploy an academic solution to an industrial problem and extend the range of test equipment that ordinarily would need to be discarded for such test requirements. We will then show the gauge repeatability and reproducibility between two testers of the same manufacture, and how using the described technique produces a better correlation, thus allowing less stringent guard-bands to guarantee the performance of those devices that have performance criteria close to the device specification. This work also goes some way to proving previous papers’ works on distortion shaping testing to enhance the spectral performance of arbitrary waveform generators.

Spectroscopic gas analysis for monitoring transient events in fast processes requires high spectrum acquisition rate with low uncertainty; however, so far high-speed spectroscopic gas detection with sufficient spectral resolution and spectral span is still challenging. Here, we propose an innovative method based on optical linear chirp chain (OLCC) for rapid acquisition of high-resolution gas spectra with a rate up to the order of MHz with 100% duty cycle, spectral resolution at 10-MHz level and spectral span > 20 GHz. The OLCC is generated by high-speed optical modulation driven by a digital arbitrary waveform generator in combination with a four-wave-mixing process, exhibiting a highly linear frequency chirp (linearity error of ~10-4) and low level of residual amplitude modulation (

The DEER (double electron-electron resonance, also called PELDOR) experiment, which probes the dipolar interaction between two spins and thus reveals distance information, is an important tool for structural studies. In recent years, shaped pump pulses have become a valuable addition to the DEER experiment. Shaped pulses offer an increased excitation bandwidth and the possibility to precisely adjust pulse parameters, which is beneficial especially for demanding biological samples. We have noticed that on our home built W-band spectrometer, the dead-time free 4-pulse DEER sequence with chirped pump pulses suffers from distortions at the end of the DEER trace. Although minor, these are crucial for Gd(III)-Gd(III) DEER where the modulation depth is on the order of a few percent. Here we present a modified DEER sequence&mdash, referred to as reversed DEER (rDEER)&mdash, that circumvents the coherence pathway which gives rise to the distortion. We compare the rDEER (with two chirped pump pulses) performance values to regular 4-pulse DEER with one monochromatic as well as two chirped pulses and investigate the source of the distortion. We demonstrate the applicability and effectivity of rDEER on three systems, ubiquitin labeled with Gd(III)-DOTA-maleimide (DOTA, 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid) or with Gd(III)-DO3A (DO3A, 1,4,7,10-Tetraazacyclododecane-1,4,7-triyl) triacetic acid) and the multidrug transporter MdfA, labeled with a Gd(III)-C2 tag, and report an increase in the signal-to-noise ratio in the range of 3 to 7 when comparing the rDEER with two chirped pump pulses to standard 4-pulse DEER.

Low frequency electron paramagnetic resonance imaging is a powerful tool to non-invasively measure the physiological status of tumors. Here, we report on the design and functionality of a rapid scan and pulse table-top imaging spectrometer based around an arbitrary waveform generator and 25mm cross-loop resonator operating at 700 MHz. Two and four-dimensional rapid scan spectral-spatial images are presented. This table-top imager is a prototype for future pre-clinical imagers.

This paper describes a design approach to a control system of power supply for high-voltage electrochemical processes such as plasma electrolytic oxidation (PEO) or high-voltage anodising (HVA), which require alternating polarisation pulses up to 750 V and a typical current density of 50&ndash, 500 mA/cm2. Complex characteristics of the electrochemical system response on applied polarisations (positive or negative) cause necessity of precise control of polarising pulse shapes for better process operation and its understanding. A device performs cycle-by-cycle pulse-width modulation (PWM) control, including feedback based on digital analysis of the instantaneous current and/or voltage output, and the desired pulse waveform stored in memory for each output polarity. The output stage has four states corresponding to positive or negative pulses, as well as open- or short-circuit conditions, with respect to an electrochemical cell. A fully programmable controller allows one to generate arbitrary waveforms, as well as their sequences, by means of &ldquo, regime designer&rdquo, software. Moreover, a smart feedback system can provide adaptation of the next pulse parameter from analysis of the process prehistory. For instance, this approach allows one to separate main electrochemical process (coating formation) and diagnosis of the phenomenon through introduction of high-voltage triangular voltage sweep pulse within a pause of the main process, which is normally carried out under a current control.

A photonics-based wideband distributed coherent aperture radar (DCAR) system is proposed and experimentally demonstrated. In the proposed system, the central controlling system and several spatially dispersed remote transceivers are connected by the optical fiber-based time synchronization network. In the central controlling system, the optical-carried orthogonal/coherent linear frequency modulated waveforms (LFMWs) are generated by a reconfigurable multi-channel optical arbitrary waveform generator (RMOAWG), and the signal processing for the echo waves is also implemented there. While in the remote transceivers, only the optical/RF and RF/optical conversions are carried out. Benefitting from the use of photonics-based methods, bandwidths of the generated radar signals can be large, improving the detection resolution of the system. Due to the centralized signal generation and processing, the remote transceivers can be simplified, reducing the system complexity. Moreover, the fiber-based distribution ensures low loss, good transportability, and great flexibility. Experimentally, a two-unit DCAR system operating in X-band with a bandwidth of 3 GHz is presented. When full coherence is achieved, signal-to-noise ratio (SNR) gains of 8.3 dB and 8.33 dB are obtained over a single radar for radar 1 and radar 2, respectively. Results are in good agreement with theoretical prediction. Theoretically, with such SNR gain, the range detection precision can be improved to about 2.6 times that of a single radar.

Moving trapped-ion qubits in a microstructured array of radiofrequency traps offers a route toward realizing scalable quantum processing nodes. Establishing such nodes, providing sufficient functionality to represent a building block for emerging quantum technologies, e.g., a quantum computer or quantum repeater, remains a formidable technological challenge. In this review, the authors present a holistic view on such an architecture, including the relevant components, their characterization, and their impact on the overall system performance. The authors present a hardware architecture based on a uniform linear segmented multilayer trap, controlled by a custom-made fast multichannel arbitrary waveform generator. The latter allows for conducting a set of different ion shuttling operations at sufficient speed and quality. The authors describe the relevant parameters and performance specifications for microstructured ion traps, waveform generators, and additional circuitry, along with suitable measurement schemes to verify the system performance. Furthermore, a set of different basic shuttling operations for a dynamic qubit register reconfiguration is described and characterized in detail. Fil: Kaushal, V.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Lekitsch, B.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Stahl, A.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Hilder, J.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Pijn, D.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Schmiegelow, Christian Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Bermudez, A.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Müller, M.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Schmidt-kaler, Ferdinand. Johannes Gutenberg University Mainz. Institute of Physics; Alemania Fil: Poschinger, U.. Johannes Gutenberg University Mainz. Institute of Physics; Alemania

Numerically optimised microwave pulses are used to increase excitation efficiency and modulation depth in electron spin resonance experiments performed on a spectrometer equipped with an arbitrary waveform generator. The optimisation procedure is sample-specific and reminiscent of the magnet shimming process used in the early days of nuclear magnetic resonance -- an objective function (for example, echo integral in a spin echo experiment) is defined and optimised numerically as a function of the pulse waveform vector using noise-resilient gradient-free methods. We found that the resulting shaped microwave pulses achieve higher excitation bandwidth and better echo modulation depth than the pulse shapes used as the initial guess. Although the method is theoretically less sophisticated than simulation based quantum optimal control techniques, it has the advantage of being free of the linear response approximation; rapid electron spin relaxation also means that the optimisation takes only a few seconds. This makes the procedure fast, convenient, and easy to use. An important application of this method is at the final stage of the implementation of theoretically designed pulse shapes: compensation of pulse distortions introduced by the instrument. The performance is illustrated using spin echo and out-of-phase electron spin echo envelope modulation experiments. Interface code between Bruker SpinJet arbitrary waveform generator and Matlab is included in versions 2.2 and later of the Spinach library.

We demonstrate the mitigation of stimulated Brillouin scattering (SBS) in a double-clad single mode Yb-doped optical fiber amplifier through external phase modulation of narrow linewidth laser radiation using optimized periodic waveforms from an arbitrary waveform generator. Such optimized phase modulation waveforms are obtained through a multi-objective Pareto optimization based on a comprehensive model for SBS in high power narrow linewidth fiber amplifiers using Brillouin parameters determined from controlled measurements. The ability of our approach to mitigate SBS is tested experimentally as a function of RMS linewidth of the modulated optical radiation, and we measure an enhancement in SBS threshold with respect to optical linewidth of ∼ 10 GHz−1. Furthermore, we discuss the dependence of the SBS threshold enhancement on key parameters such as the amplifier length and the period of the optimized waveforms. Through simulations we find that waveforms of sufficiently long periods and optimized for a relatively long fiber (10 m) are effective for SBS suppression for shorter fibers as well. We also investigate the effect of increase in the bandwidth and amplitude of the modulation waveform on the SBS threshold enhancement observed at higher optical linewidth.

Combining with the IP core advantage of FPGA, a signal generator which can generate arbitrary waveform is designed on the basis of direct digital synthesis technology in this paper. The INTEL company’s Cyclone IV series EP4CE6F17C8N is used as the control core and the front-end interface design is carried out by XMAL. The software control operation of the logical processing interface is realized through C#. The signal generator has the characteristics of single cycle waveform with 256 sampling points, clear spectrum analysis, higher purity and high precision. The arbitrary waveform displayed on oscilloscope is wonderful after filtering out high frequency signal by seven order butter worth filter.

In this paper a digital architecture for generating piecewise-linear arbitrary waveforms is presented. The proposed design is able to generate a piecewise-linear periodic signal by only using a minimum number of input data (breakpoints). The generator circuit implements a hybrid scheme which takes advantage of two methods: the purely piecewise-linear interpolation and the lookup-table structure. From the piecewise-linear method exploits the characteristic of a reduced memory requirement as well as the capability of automatically construct a waveform by repetitive (iterative) function evaluations. From lookup-table makes use of the simplicity in hardware implementation and the higher processing speed. In order to verify the performance of this proposal, three piecewise-linear waveforms have been successfully implemented in a ATMEGA32 microcontroller. Experimental results show a fast execution speed and a reduced memory demand in the proposed circuit realization.