High-speed Pulse Research Articles

Prognostics of connection defects in electronics modules

Electrical connection anomalies are widely known as problems in industrial applications. In machinery these can occur in a printed circuit board, for instance in a control unit, in the interfacing connectors, or even in the inter-connections within a sensor or an actuator. Different methods have been proposed in the last decades to detect these anomalies. Most of these methods are working on non-powered systems for instance by measuring reflections of a high speed pulses (reflectometry principle). However, the most challenging connection anomalies have intermittent nature, often in applications where vibration stresses are dominant (e.g. automotive sector). In these cases, detecting these anomalies in a live (powered) system is needed. Although some methods exist which allow such a detection, they are expensive, limiting the targeted applications (e.g. aeronautics). We developed low-cost methods to detect connections anomalies in live systems. These methods use measured signals, for instance across a sensor, not only to detect a fault in its connections but also to localize the position of such a fault. The used ‘diagnostic’ systems will trigger a warning at a very early stage of the connection anomaly. The proposed methods have been applied and validated on different industrial cases and proved to be able to localize within 30 cm accuracy and to detect connection degradation before corrupting the operation of the system.

High-speed, high-voltage pulse generation using avalanche transistor.

In this work, the conduction mechanism of avalanche transistors was demonstrated and the operation condition for generating high-speed pulse using avalanche transistors was illustrated. Based on the above analysis, a high-speed and high-voltage pulse (HHP) generating circuit using avalanche transistors was designed, and its working principle and process were studied. To improve the speed of the output pulse, an approach of reducing the rise time of the leading edge is proposed. Methods for selecting avalanche transistor and reducing the parasitic inductance and capacitance of printed circuit board (PCB) were demonstrated. With these instructions, a PCB with a tapered transmission line was carefully designed and manufactured. Output pulse with amplitude of 2 kV and rise time of about 200 ps was realized with this PCB mounted with avalanche transistors FMMT417, indicating the effectiveness of the HHP generating circuit design.

The Research of Circular Interpolation Motion Control Based on Rectangular Coordinate Robot

The high-speed pulse outputs of PLC can control motion of stepper motor or servo motor. So PLC can complete interpolation function which CNC can do using a kind of simple algorithm. What’s more, the PLC can be developed to be a controller of economical CNC machine tools. Based on the experiment platform of modern robot industrial, the paper introduced how to control the motion of servo system by PLC in detail, and completed the two-dimensional interpolation program through PLC using the direct target tracking as interpolation algorithm. The direct target tracking algorithm could form a series of micro straight line segments approach the desired interpolation trajectory through directly calculating a series of minimum interval points on the interpolation line and connecting these points end to end. Compared to the single pulse interpolation, the direct target tracking algorithm simplified interpolation algorithm and adapted to the PLC program, so it is suitable to economical CNC system. By programming and running in the experimental platform, it can achieve better results using the direct target tracking method as interpolation procedures.

Low-reflectance laser-induced surface nanostructures created with a picosecond laser

Using high-speed picosecond laser pulse irradiation, low-reflectance laser-induced periodic surface structures (LIPSS) have been created on polycrystalline silicon. The effects of laser fluence, scan speed, overlapping ratio and polarization angle on the formation of LIPSS are reported. The anti-reflective properties of periodic structures are discussed, and the ideal LIPSS for low surface reflectance is presented. A decrease of 35.7 % in average reflectance of the silicon wafer was achieved over the wavelength range of 400–860 nm when it was textured with LIPSS at high scan speeds of 4000 mm/s. Experimental results of broadband reflectance of silicon wafers textured with LIPSS have been compared with finite difference time domain simulations and are in good agreement, showing high predictability in reflectance values for different structures. The effects of changing the LIPSS profile, fill factor and valley depth on the surface reflectance were also analyzed through simulations.

Study of multiplexer based on surface plasmon-polaritons for communication devices

Surface plasmon-polaritons provide a unique opportunity to create devices for signals localization and control on an optical subwavelength scale. They can be used as promising data carriers in highly integrated nanooptical transmission systems. Dielectric waveguides based on surface plasmon-polaritons (SPP) arise a particular interest in devices that will run in ultra high-speed data transmission ranges. The paper demonstrates the samples of the four-channel multiplexer based on SPP that works with ultra high-speed pulses. The multiplexer samples are developed using quite simple, but an extremely accurate method of phased optical lithography (POL). For excitation of the SPP, the 800 nm Ti: sapphire laser with a pulse frequency of 27 fs is used. We have shown the ultra high-speed distribution of SPP on the 10×5 µm multiplexer. Experimental studies are tested in the simulation by a finite difference method in the time domain. Good agreement between the experimental results and numerical simulation is obtained.

Two-Volt Josephson Arbitrary Waveform Synthesizer Using Wilkinson Dividers.

The root-mean-square (rms) output voltage of the NIST Josephson arbitrary waveform synthesizer (JAWS) has been doubled from 1 V to a record 2 V by combining two new 1 V chips on a cryocooler. This higher voltage will improve calibrations of ac thermal voltage converters and precision voltage measurements that require state-of-the-art quantum accuracy, stability, and signal-to-noise ratio. We achieved this increase in output voltage by using four on-chip Wilkinson dividers and eight inner-outer dc blocks, which enable biasing of eight Josephson junction (JJ) arrays with high-speed inputs from only four high-speed pulse generator channels. This approach halves the number of pulse generator channels required in future JAWS systems. We also implemented on-chip superconducting interconnects between JJ arrays, which reduces systematic errors and enables a new modular chip package. Finally, we demonstrate a new technique for measuring and visualizing the operating current range that reduces the measurement time by almost two orders of magnitude and reveals the relationship between distortion in the output spectrum and output pulse sequence errors.

New Design of Scan Flip-Flop to Increase Speed and Reduce Power Consumption

In this paper, a novel low-power and high-speed pulse triggered scan flip-flop is presented, in which short circuit current is controlled. Switching activity is decreased to reduce the consumed power of the scan flip-flop. Also, the total number of transistors through the path from input to the output is reduced and so the delay of the proposed scan flip-flop is decreased. Simulation results show 12% and 29% reduction in power consumption and delay of the proposed scan flip-flop, respectively. The results are given by comparison of our work with other scan flip-flops at 50% data switching activity.

Multiwavelength 25-GHz picosecond pulse generation with phase modulation and double-side Mamyshev reshaping.

We demonstrate a simple, robust, and cost-effective method of generating high-speed multiwavelength picosecond optical pulses. This method is based on chirp compression of phase-modulated light, followed by nonlinear pulse compression and reshaping with a double-side Mamyshev reshaper. We show that this method becomes power efficient when the repetition rate is increased to 25GHz. Wavelength-tunable optical pulses with a repetition rate of 25GHz and pulse width of ∼2 ps, which can be temporally multiplexed to 100GHz, are experimentally obtained over a large spectral range with moderate electrical and optical power. Simultaneous pulse generation on four wavelengths is demonstrated.

On Laser Ranging Based on High-Speed/Energy Laser Diode Pulses and Single-Photon Detection Techniques

This paper discusses the construction principles and performance of a pulsed time-of-flight (TOF) laser radar based on high-speed (FWHM $\sim$ 100 ps) and high-energy ( $\sim$ 1 nJ) optical transmitter pulses produced with a specific laser diode working in an “enhanced gain-switching” regime and based on single-photon detection in the receiver. It is shown by analysis and experiments that single-shot precision at the level of 2…3 cm is achievable. The effective measurement rate can exceed 10 kHz to a noncooperative target (20% reflectivity) at a distance of $> 50 \hbox{m}$ , with an effective receiver aperture size of $2.5 \hbox{cm}^{2} $ . The effect of background illumination is analyzed. It is shown that the gating of the SPAD detector is an effective means to avoid the blocking of the receiver in a high-level background illumination case. A brief comparison with pulsed TOF laser radars employing linear detection techniques is also made.

A Reconfigurable 50-Mb/s-1 Gb/s Pulse Compression Radar Signal Processor With Offset Calibration in 90-nm CMOS

This paper presents a reconfigurable mixed-signal-processing circuit for high-speed pulse compression radar (PCR). Mixed-signal design techniques incorporate calibration and adaptation to improve the performance of a PCR receiver. Adaptive bandwidth PCR is an important feature for maximizing the dynamic range of a low-power radar system. The baseband signal processor includes a variable gain amplifier, 4-bit digital-to-analog converter, high-speed analog correlator, passive integrator, a 4-bit flash analog-to-digital converter, and a multi-range delay-locked loop. This proposed system is fabricated in 90-nm CMOS and can be configured to work from 50 Mb/s to 1 Gb/s with 2/3/5/7-bit Barker codes. The proposed calibration techniques improve the sidelobe reduction to 15.6 dB at 1 Gb/s. The total power consumption is 42 mW at the peak rate of 1 Gb/s for 15-cm range resolution.

Two novel low power and very high speed pulse triggered flip‐flops

SummaryTwo novel low power and high‐speed pulse triggered flip‐flops were presented in this paper. Short circuit current was controlled, and race condition between pull‐up and pull‐down branches was removed, which caused reduction of power consumption. On the other hand, the number of stack transistors in the discharging path was reduced which decreased delay of the flip‐flops. The first proposed flip‐flop reduced the number of transistors and the second proposed flip‐flop used conditional data mapping and removed floating node of the first flip‐flop. Post‐layout simulation result showed that the first proposed flip‐flop reduced 21% of power delay product and the second proposed flip‐flop reduced 16% of power delay product in comparison with other flip‐flops in 50% of data switching activities. Copyright © 2014 John Wiley & Sons, Ltd.

A low-power photonic quantization approach using OFDM subcarrier spectral shifts.

Photonic analog-to-digital conversion and optical quantization are demonstrated, based on the spectral shifts of orthogonal frequency division multiplexing subcarriers and a frequency-packed arrayed waveguide grating. The system is extremely low-energy consuming since the spectral shifts are small and generated by cross-phase modulation, using a linear-slope high-speed and low-jitter pulse train generated by a mode locked laser diode. The feasibility of a 2, 3 and 4-bit optical quantization scheme is demonstrated.

High-speed odor transduction and pulse tracking by insect olfactory receptor neurons.

Sensory systems encode both the static quality of a stimulus (e.g., color or shape) and its kinetics (e.g., speed and direction). The limits with which stimulus kinetics can be resolved are well understood in vision, audition, and somatosensation. However, the maximum temporal resolution of olfactory systems has not been accurately determined. Here, we probe the limits of temporal resolution in insect olfaction by delivering high frequency odor pulses and measuring sensory responses in the antennae. We show that transduction times and pulse tracking capabilities of olfactory receptor neurons are faster than previously reported. Once an odorant arrives at the boundary layer of the antenna, odor transduction can occur within less than 2 ms and fluctuating odor stimuli can be resolved at frequencies more than 100 Hz. Thus, insect olfactory receptor neurons can track stimuli of very short duration, as occur when their antennae encounter narrow filaments in an odor plume. These results provide a new upper bound to the kinetics of odor tracking in insect olfactory receptor neurons and to the latency of initial transduction events in olfaction.

Repetition-Rate Multiplication of a 10-GHz Mode-Locked Laser via Coding the Spectral Intensity and Phase

We report high-speed pulse train generation from a relatively low-speed 10-GHz mode-locked laser by means of line-by-line spectral coding. To increase the pulse repetition rate multiplication (RRM) factor, we combine coding schemes for both spectral intensity and phase by placing a simple mask at the coder focal plane. The resulting RRM factor, determined by multiplying the RRM factors of the individual coding schemes, rises as high as 16. To verify the generated pulses, the optical spectra and autocorrelation traces are examined.

Fabrication and Characterization of a Vacuum Encapsulated Curved Beam Switch for Harsh Environment Application

A vacuum-encapsulated silicon switch with a curved electrode is characterized for operation in harsh environments. An ultraclean vacuum encapsulation process (episeal) seals the switch after release, providing a pristine operating environment for switching operations. In these devices, the curved beam of the actuator enhances the overdrive voltage tolerance to be more than 100 V. The ON/OFF cycle tests were carried out up to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> cycles at room temperature, and at least 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> cycles under an elevated temperature of 300°C. Throughout the 300°C tests, an average contact resistance of ~ 28 kΩ is measured, demonstrating the stability of the contact. Finally, high speed pulse I-V monitoring unit was used to observe 13-μs switching speed.

A New Design of Laser Pulse Receiver in the Automatic Control System

The existing problem of current laser pulse receiving system is that the laser pulses width is too narrow to be directly collected. And the consistency of the four signals acquisition is very strict. To deal with these problems, a new design of laser pulse receiver will be introduced in this article. This laser pulse receiving system includes the following structures: new high-speed laser pulse receiving hardware based on CPLD and Four-Quadrant Detectors, new peak-hold circuit of laser pulse, high-speed parallel ADC system, and processing data with fast interpolation algorithm in a Floating-Point DSP. Through the new design of high-speed parallel ADC system, the receiving system is able to simultaneously complete the timing of four high-speed laser pulse signals acquisition and the storing of data. The new construction of high-speed parallel acquisition is a core module in this design. And a new flow how to the DSP handle the data with fast interpolation algorithm will also be introduced in this article.

Influence of pre-injection control parameters on main-injection fuel quantity for an electronically controlled double-valve fuel injection system of diesel engine

A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment. The accuracy of the model is validated through comparison with experimental data. The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed. In the spill control valve mode, main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time. In the needle control valve mode, main-injection fuel quantity increases with rising multi-injection dwell time; this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths. Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes; the variation in main-injection quantity is in the range of 1 mm3.

Plasmodynamic synthesis of ultradispersed iron oxides

Results of a pilot study of direct plasmochemical synthesis of ultradispersed crystalline iron oxide phases in a high-speed pulse jet of iron-containing electrodischarge plasma that effluxes into a closed volume with the air atmosphere are presented. The synthesized powder contains all main oxide phases, including magnetite Fe3O4, maghemite γ-Fe2O3, and hematite α-Fe2O3. An important feature of the method is the formation of the metastable e-Fe2O3 phase under normal conditions. The minimum average size of coherently diffracting domains (CDD) (particles) of the magnetic phases is observed when they are synthesized at air pressure of 1.0 atm. The powders have high magnetic properties comparable with those of compact iron oxides.

A Comprehensive Study of Actively Mode-Locked Fiber Optical Parametric Oscillators for High-Speed Pulse Generation

We perform a comprehensive study on the implementation of active harmonic and rational harmonic mode-locking of a fiber optical parametric oscillator (FOPO). In particular, the effect of pump parameters and cavity designs on the characteristics of the generated pulses are analyzed. Two methods of frequency multiplication in FOPOs are discussed and compared and we show that we can generate optical pulses with very high-repetition-rate (up to 240 GHz) using rational harmonic mode-locking. We find that optical pulses with short duration can be obtained using pump pulses with small duty cycle, large pump power, and an intra-cavity optical filter with proper bandwidth. In addition, optical pulses with low root-mean-square timing jitter are achievable when no pump phase modulation is applied and hybrid gain of erbium-doped fiber amplifier and parametric amplifier is used. High supermode noise suppression ratio is achieved by taking advantage of the fast parametric gain and the combined effect of self-phase modulation and spectral filtering. We conclude that synchronous-pumping of an actively mode-locked FOPO offers many advantages in terms of reducing the cavity loss, increasing the modulation frequency, enabling rational harmonic mode-locking, and applications to all-optical clock recovery.

A FET Structure Field Emission Device With High-Speed Pulse Signal Control

In this letter, a current driving method by using a field-effect transistor (FET)-modulated structure for a carbon-nanotube field emission device (FED) is reported. This device can obtain a stable large emission current modulated value by tunneling the gate voltage of the metal-oxide-semiconductor FET, i.e., from 2 to 128 μA (the anode voltage is 1000 V). Moreover, a subpixel FED and a periphery circuit are also designed. This device can dramatically produce a working pulse emission current (peak current: 350 μA) by controlling a low-voltage high-speed pulse signal (peak: 22.5 V). Compared with the previous triode FEDs, this FET-modulated device has more advantages in driving circuit design. If the integrated process for this device can be realized, it will promote the FED's application to launch on the market.