Narrow Pulse Generator Research Articles

A Digitally Controlled Multichannel Spectrally Efficient Low-Power Transceiver for Ultra-Wideband Cognitive Radio Applications

A multichannel transceiver design with low hardware complexity, flexibility and efficient spectrum use intended for Impulse Radio (IR) Ultra-Wideband (UWB) apertures, is proposed in this paper. The transceiver supports 14 channels and is implemented in TSMC CMOS process. The transmitter adopts a symmetrical triangular narrow pulse generator, a multiband LC-VCO, a mixer and a Variable-Gain Amplifier. A digital control of transmitter output power and carrier frequency is achieved by a current-steering Digital-to-Analog Converter (CS-DAC). The receiver follows the noncoherent Energy Detection (ED) scheme including Low-Noise Amplifier (LNA) which takes the benefits of the body biasing technique to further reduce power consumption, squarer and comparator. The LNA achieves high gain of up to 30[Formula: see text]dB allowing to enhance the receiver sensitivity which is [Formula: see text]83.7[Formula: see text]dBm at 25[Formula: see text]Mbps. The transmitter provides output pulses with a width of 3[Formula: see text]ns, a pulse repetition rate of 20[Formula: see text]ns and a maximum Power Spectral Density (PSD) of [Formula: see text]42[Formula: see text]dBm/MHz. The power consumptions of transmitter and receiver are 35.6[Formula: see text]pJ/bit and 0.207[Formula: see text]nJ/bit at 25[Formula: see text]Mbps, respectively. Maximizing utilization of the scarce wireless spectrum, enhancing spectral flexibility and efficiency and reducing power consumption are the main contributions brought by this work, enabling this transceiver to be able to deal with the current debate on producing single multifunctional Cognitive Radio (CR) UWB systems.

Design Pulse Source for TDR System with Large Deformation Distributed Measurement

Distributed measurement of rock-soil deformation is one of the important technologies for geological disaster monitoring. TDR combined with helical sensing cable enables large deformation distributed measurement. A TDR system for distributed measurement of large deformation combines narrow pulse generator circuit, helical sensing cable, reflected wave processing and sampling circuit. The current work mainly includes the design of narrow pulse generation circuit based on avalanche transistor and step recovery diode. The suitable parameters of the components are given, and the nanosecond pulse with larger amplitude, faster falling edge and rising edge is obtained.

A Multiband, Spectrally-Efficient Impulse Radio Transmitter Design with Low-Complexity CMOS Pulse Generator for IEEE 802.15.4a Application

A novel multiband impulse radio ultra-wideband (MB-IR-UWB) transmitter with an energy-efficient and low-complexity pulse generator design technique compliant with the IEEE 802.15.4a standard is investigated in this paper. This transmitter is made up of a new differential narrow triangular pulse generator, a new multiband voltage-controlled oscillator (VCO), an active mixer and a variable-gain power amplifier (PA). It operates at 14 UWB bands and generates an output signal with the duration of 3[Formula: see text]ns, more than 500[Formula: see text]MHz of channel bandwidth and more than 20[Formula: see text]dB of sidelobe suppression, while achieving an average energy efficiency of 51.36 pJ/pulse from 1.4-V supply. Improving spectral flexibility and worldwide compliance is the major contribution brought by this paper to make this circuit as a multifunction wireless device well suited for low-cost, low-power multiband applications.

超宽带窄脉冲产生方法比较

超宽带窄脉冲产生方法比较

Background-free microwave pulse generator based on both bright and dark temporal gate and a single photodetector

A novel approach to generating background-free microwave pulse based on both bright and dark temporal gate and a single photodetector is proposed and demonstrated. Incoherent wavelength-to-time conversion (WTTC) using only bright or dark gate renders the generation of positive or negative pulse separately. By using both gates simultaneously, background-free pulse is realized with enhanced amplitude compared with that obtained using only bright or dark gate. A dual-output intensity modulator functions as both the bright and dark gate. Narrow drive pulse is provided by the combination of two polarity-opposite electrical pulses with a relative time-delay, which releases the requirement of expensive narrow-pulse generator. Incoherent WTTC using dark gate is demonstrated experimentally. The system resolution remains the same as that using bright gate. Furthermore, UWB pulse with 10-dB bandwidth of 3.8-GHz is generated based on 1-Gb/s gate driven by 1-Gb/s data sequence. Several other background-free pulses are generated to verify the tunability of central frequency, pulse envelope, duty cycle, and repetition rate. In addition, the effect of gate width on WTTC is explored experimentally. With narrower gate width, higher system solution and maximum achievable frequency can be implemented. 10.4-GHz and 14.5-GHz background-free pulses are generated when using 1-Gb/s and 10-Gb/s gate respectively.

Low‐power implantable CMOS bipolar Gaussian monocycle pulse generator

A novel CMOS bipolar Gaussian monocycle pulse generator consisting of single to differential circuit, narrow pulse generator and Gaussian pulse-shaping circuit is presented. Without traditional LC filtering or multi-channel pulses combination, the proposed generator can be low power and low complexity. Fabricated in a 180 nm standard CMOS process, the test results show that the bipolar Gaussian monocycle pulse can be generated correctly, the power consumption is 1 mW at 200 MHz pulse repeating frequency and the chip core area is only 0.08 mm2under the power supply of 1.8 V, demonstrating the proposed generator with the advantages of low power and low complexity is suitable for implantable IR-UWB transmitter.

Fractal Based Triple Band High Gain Monopole Antenna

AbstractA novel triple-band microstrip fed planar monopole antenna is proposed and investigated. A fractal antenna is created by iterating a narrow pulse (NP) generator model at upper side of modified ground plane, which has a rhombic patch, for enhancing the bandwidth and gain. Three iterations are carried out to study the effects of fractal geometry on the antenna performance. The proposed antenna can operate over three frequency ranges viz, 3.34–4.8 GHz, 5.5–10.6 GHz and 13–14.96 GHz suitable for WLAN 5.2/5.8 GHz, WiMAX 3.5/5.5 GHz and X band applications respectively. Simulated and measured results are in good agreements with each others. Results show that antenna provides wide/ultra wide bandwidths, monopole like radiation patterns and very high antenna gains over the operating frequency bands.

Stimulated Raman scattering in the approximation of unidirectional propagation in a medium with static dipole moments

The evolution equations of two-frequency stimulated Raman scattering in a molecular quasithree- level medium with static dipole moments have been derived in the approximations of the nondepletion of the pump field and the unidirectional propagation of the Stokes field. Completely integrable particular cases of the resulting system of equations have been found. New mechanisms of controlling the parameters of microwave pulses generated in such a system have been studied within this model. The numerical analysis and particular exact solutions demonstrate the possibility of switch between the regimes of generation of narrow Stokes field pulses and nearly rectangular pulses.

Behavior of metals Induced by magnetic pulse loading

The investigation of copper and aluminum ring samples was carried out using magnetic pulse loading. Two modifications of the magnetic pulse technique were used. They were based on a GKVI-300 high-voltage narrow-pulse generator Morozov et al. (2011) [1]. It is possible using these two approaches to decrease the period of the harmonic load up to 100 ns. The study of fracture surfaces of aluminum and copper samples after the test was carried out on an optical microscope Axio-Observer-Z1-M in a dark field, and study of the cross sections structure – in the bright field or C-DIC. The structure has been studied in cross sections after appropriate etching. Grain size and the number of pores on the surface of cross sections were determined after etching. Microhardness was measured on a PMT-3 device with a load of 20 g. The optical micrographs of aluminum demonstrate that the long pulse causes almost fully ductile fracture. In the case of the short pulse, the number of fibers decreases: the fracture surface exhibits the signs of both ductile cup fracture and brittle crystalline fracture with cracks, which are sometimes rather deep. In addition, the short pulse results in twinning, which seems surprising for aluminum featuring a high stacking fault energy. It is seen that under short loading dynamic recrystallization occurs. As for copper samples before loading they were in the form of single crystal and after loading their structure due to dynamic recrystallization consists of small grain. The specimen with notch has more developed dynamic recrystallization shear bands.

A novel approach for the design of a modified excitation signal using a narrow pulse generator for high‐resolution time‐domain reflectometry applications

ABSTRACTIn this article, a novel modified stimulus signal is used to improve the accuracy of localizing discontinuities for time‐domain reflectometry (TDR) measurements. This pulse shaping puts more energy at higher frequencies in contrast with conventional step or impulse TDR. Hence, a wider bandwidth is available to achieve higher accuracy for precise spatial localization. The proposed modified TDR is less expensive than a vector network analyzer, very practical as it is based on more realistic signals rather than assuming ideal impulses or steps. Simulated and measured results are presented to validate the accuracy of the proposed approach. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2987–2990, 2014

A UWB wireless capsule endoscopy device.

Wireless capsule endoscopy (WCE) presents many advantages over traditional wired endoscopic methods. The performance of WCE devices can be improved using high-frequency communication systems such as Impulse Radio-Ultra-Wideband (IR-UWB) to enable a high data rate transmission with low-power consumption. This paper presents the hardware implementation and experimental evaluation of a WCE device that uses IR-UWB signals in the frequency range of 3.5 GHz to 4.5 GHz to transmit image data from inside the body to a receiver placed outside the body. Key components of the IR-UWB transmitter, such as the narrow pulse generator and up-conversion based RF section are described in detail. This design employs a narrowband receiver in the WCE device to receive a control signal externally in order to control and improve the data transmission from the device in the body. The design and performance of a wideband implantable antenna that operates in the aforementioned frequency range is also described. The operation of the WCE device is demonstrated through a proof-of-concept experiment using meat.

Picosecond Soliton Pulse Generation Using a PANDA System for Solar Cells Fabrication

A proposed system of extremely narrow multisoliton pulse generation is presented. A PANDA system can be used to create signals in the form of chaotic noise inserted into an add/drop system. The capacity of the output signals can be improved by generation of multisoliton pulses with pulse width (FWHM) and free spectrum range (FSR) of picometres and picoseconds size. Multisoliton of dark and bright can be generated and propagated within the system. This system can be used to improve the scribing of the micro channels or the solar cell thin films. Using the ultra-short laser pulses, the micro channels with exact depths and well-defined outlines can be generated and fabricated without causing any damage to the ultra-thin-film solar cells. Results obtained show that controlling of the signals can be performed when the additional Gaussian laser pulse is used in the add port of the nonlinear system. In this work high capacity of narrow spatial and temporal multisoliton pulse with FWHM of 5 pm and 2.6 ps and FSR of 190 pm and 101 ps were simulated respectively where the central wavelength of the input power was selected to 1.55m.

Metallic Ring Fracture Induced by Magnetic Pulse Loading of Short Duration

The investigation of copper and aluminum ring samples was carried out using magnetic pulse loading. Two modifications of the magnetic pulse technique were used. They were based on a GKVI-300 high-voltage narrow-pulse generator Morozov et al.(2011). It is possible using these two approaches to decrease the period of the harmonic load up to 100 ns. The study of fracture surfaces of aluminum and copper samples after the test was carried out on an optical microscope Axio-Observer-Z1-M in a dark field, and study of the cross sections structure - in the bright field or C-DIC. The structure has been studied in cross sections after appropriate etching. Grain size and the number of pores on the surface of cross sections were determined after etching. Microhardness was measured on a PMT-3 device with a load of 20g. The optical micrographs of aluminum demonstrate that the long pulse causes almost fully ductile fracture. In the case of the short pulse, the number of fibers decreases: the fracture surface exhibits the signs of both ductile cup fracture and brittle crystalline fracture with cracks, which are sometimes rather deep. In addition, the short pulse results in twinning, which seems surprising for aluminum featuring a high stacking fault energy. It is seen that under short loading dynamic recrystallization occurs. As for copper samples before loading they were in the form of single crystal and after loading their structure due to dynamic recrystallization consists of small grain. The specimen with notch has more developed dynamic recrystallization shear bands.

A 3–5 GHz low-power high-speed radiated power tuning UWB transmitter

To satisfy the different radiated power requirements for the ultra-wideband (UWB) data transmitting in the implantable electronic devices or the wireless component interconnections, a novel low-power high-speed UWB transmitter with radiated power tuning was proposed. The tunable radiated power is achieved by a UWB RF buffer with a peak value controller. The designed low-complex narrow pulse generator and digital ring on–off VCO ensure a high speed transmitting. The low power is realized by using a subtractor to eliminate the base-band component from the output of the VCO and making the UWB RF buffer and the VCO operating in standby mode. The design was fabricated by a standard 0.18μm CMOS technology. The test results show that the design can achieve maximum data-rate of 250Mbps, frequency bandwidth from 3 to 5GHz, radiated power tuning from −40dBm to −60dBm, low-power of 8pJ/bit, and small circuit area of 0.18mm2.

20-pJ/Pulse 250 Mbps Low-Complexity CMOS UWB Transmitter for 3–5 GHz Applications

This letter presents a CMOS on-off keying 3-5 GHz ultra-wideband (UWB) transmitter with low complexity, low power and high speed. In the transmitter, a new differential narrow triangular pulse generator using push and pull integrating technique was designed for reducing quiescent current and common-mode interference, and a new complementary switch mode on-off voltage controlled ring oscillator (VCRO) was proposed by breaking the oscillation loop instead of breaking the power to avoid base-band energy without extra shaping filter. Without using delay resistor and capacitor in the VCRO, the transient response speed of the transmitter can be increased by only utilizing the parasitic resistances and capacitances. The design was successfully implemented with a 0.18 μm CMOS technology. The test results show that the new UWB transmitter can obtain a sidelobe rejection of more than 20 dB, a low energy consumption of 20 pJ/pulse at 250 Mbps, and a small core chip size of 0.08 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Generation of tunable narrow bandwidth nanosecond pulses in the deep ultraviolet for efficient optical pumping and high resolution spectroscopy

Nanosecond optical pulses with high power and spectral brightness in the deep ultraviolet (UV) region have been produced by sum frequency mixing of nearly transform-limited-bandwidth IR light originating from a home-built injection-seeded ring cavity KTiOPO(4) optical parametric oscillator (OPO) and the fourth harmonic beam of an injection-seeded Nd:YAG laser used simultaneously to pump the OPO with the second harmonic. We demonstrate UV output, tunable from 204 to 207 nm, which exhibits pulse energies up to 5 mJ with a bandwidth better than 0.01 cm(-1). We describe how the approach shown in this paper can be extended to wavelengths shorter than 185 nm. The injection-seeded OPO provides high conversion efficiency (>40% overall energy conversion) and superior beam quality required for highly efficient downstream mixing where sum frequencies are generated in the UV. The frequency stability of the system is excellent, making it highly suitable for optical pumping. We demonstrate high resolution spectroscopy as well as optical pumping using laser-induced fluorescence and stimulated emission pumping, respectively, in supersonic pulsed molecular beams of nitric oxide.

Multi-wavelength generation of an extremely narrow pulse using a ring resonator system for bio-cells microscopy

We propose a new system of an extremely narrow light pulse generation for optical microscopy applications using a nonlinear ring resonator system. The system consists of one nano and three micro-optical ring resonators, which can be used to generate the 50 fm (10 −15 m) optical spectral width at the broad wavelength spectrum. By using a soliton pulse with a pulse width of 50 ps, peak power of 1 W, center wavelength at 550 nm, and after the soliton pulse is launched into the first ring device, the chaotic pulses are generated within the first ring. The chaotic filtering behaviors are performed by using the second and the third ring devices, whereas the extremely short pulse, i.e. narrow spectral width, can be generated by using the extended nano-ring device. The broad spectrum of the harmonic waves is generated and filtered, which is of use in optical tomography. Results obtained have shown that the generation of the broad spectrum of short pulse with width 100 fm and peak power 60 mW is achieved. The possibility of using such a system for nondestructive bio-cells microscopy, for visualizing bio-cells and for bio-cells tomography is also discussed in detail.

An extremely narrow UV pulse generation using a micro- and nano-ring system for pico-lithographic resolution

We propose a new technique of an extremely narrow ultraviolet (UV) pulse width generation for pico-lithography technology using a nonlinear ring resonator system. A system consists of three micro- and a nano-optical ring resonators, which can be used to generate the 50 pm (10 −12 m) optical spectral width at the ultraviolet wavelength. By using a soliton pulse with a pulse width of 50 ns, 1 W peak power, center wavelength at 1550 nm, after the soliton pulse is launched into a first ring device, the chaotic pulses are generated within the first ring. The chaotic filtering behaviors are performed by using the second and third ring devices, whereas the extremely short pulse, i.e. narrow spectral width, can be generated by using the extended nano-ring device. The broad spectrum of the harmonic waves is generated and filtered, especially the generation of third harmonic wave, which is known as the ultraviolet wavelength, is achieved, which is capable of forming pico-lithographic resolution. Results obtained have shown that the generation of the spectral width of 50 pm at a wavelength of 511.125 nm, with peak power at 35 mW is achieved.

Generalized optical filters using a nonlinear micro ring resonator system

We present the interesting results of nonlinear behaviors of a soliton pulse within a nonlinear micro ring resonator system, where the optical filter characteristics in terms of frequency, wavelength and time can be functioned by using the chaotic filter within the micro ring resonator system. There are three forms of applications using the chaotic soliton behaviors and optical filter characteristics presented. Firstly, the simultaneous up-link and down-link frequency bands can be filtered and the required frequency bands obtained. Secondly, we propose the simple system of an extremely narrow light pulse generation over the spectrum range, where the required wavelengths can be filtered and obtained. Finally, a simple system of fast light generation by using a soliton pulse circulating in the integrated micro ring devices is proposed. Using such a system, an attosecond pulse and beyond can be easily filtered and obtained.

Wide Pulse Combined With Narrow-Pulse Generator for Food Sterilization

This paper proposes a wide pulse combined with a narrow-pulse generator for solid-food sterilization. The proposed generator is composed of a full-bridge converter in phase-shift control to generate a high dc-link voltage and a full-bridge inverter associated with an L-C network and a transformer to generate wide pulses combined with narrow pulses. These combined pulses can prevent undesired strong air arcing in free space, reduce power consumption, and save power components, while sterilizing food effectively. The converter and inverter can be operated at high frequencies and with pulse width-modulation control; thus, its weight and size can be reduced significantly, and its efficiency can correspondingly be improved. Experimental results obtained from a prototype with plusmn10-kV wide pulses combined with plusmn10-kV narrow pulses and with 10- to 50-kW peak output power, depending on pulsewidth of the output pulses, have demonstrated its feasibility.