Monocycle Pulse Generator Research Articles

Photonic ultrawideband monocycle pulse generation using a single electro-optic modulator

A compact approach to photonic-assisted ultrawideband (UWB) monocycle pulse generation is proposed and experimentally demonstrated based on the wavelength dependence of the half-wave voltage of a Mach-Zehnder modulator (MZM). By employing a single MZM with dual-wavelength injection at around 1310 and 1550 nm, a pair of polarity-reversed monocycle pulses with the full width at half-maximum of about 80 ps and the fractional bandwidth of greater than 160% can be generated. The experiment results agree well with the theoretical prediction. The simple setup and the convenience to control the monocycle pulse polarity are favorable for future applications.

An Electrically Switchable Optical Ultrawideband Pulse Generator

A novel electrically switchable optical ultrawideband (UWB) pulse generator that is capable of generating both Gaussian monocycle and Gaussian doublet pulses by using a polarization modulator (PolM) and a fiber Bragg grating is proposed and experimentally demonstrated. The polarity and the shape of the generated UWB pulses can be electrically switched by adjusting the voltages applied to two arbitrary wave plates (AWPs), which are incorporated at the input and the output of the PolM to adjust the polarization state of the lightwaves. The key component in the UWB pulse generator is the PolM, which is a special phase modulator that can support both transverse electric and transverse magnetic modes but with opposite phase modulation indexes. Depending on the polarization state of the incident lightwave to the PolM that is linearly polarized and aligned to one principle axis of the PolM or circularly polarized, UWB monocycle or doublet pulses are generated. The polarity of the UWB pulses can be electrically switched by adjusting the voltages applied to the AWPs. The proposed system is implemented, and the generation of UWB monocycle and doublet pulses is experimentally demonstrated. Gaussian monocycle and doublet pulses with a fractional bandwidth of about 150% and 160% are experimentally generated. The proposed electrically switchable optical UWB pulse generator has the potential for applications in UWB communications and radar systems that employ pulse polarity modulation and pulse shape modulation schemes.

Switchable optical UWB monocycle and doublet generation using a reconfigurable photonic microwave delay-line filter

Optically switchable Ultra-Wideband (UWB) monocycle and doublet pulse generation using an optically reconfigurable photonic microwave delay-line filter is proposed and demonstrated. The microwave filter can be reconfigured as a two- or three-tap microwave filter with coefficients of (1, -1) or (1, -2, 1). The function of the two- or three-tap microwave filter is equivalent to an operation of a first- or second-order difference, which can be approximated as a first- or second-order derivative. When a Gaussian pulse is inputted to the two- or three-tap microwave delay-line filter, a Gaussian monocycle or doublet pulse is generated. The proposed photonic microwave delay-line filter is implemented using a polarization modulator (PolM), a length of polarization maintaining fiber (PMF), and a balanced photo-detector (BPD). In the experiment, Gaussian monocycle and doublet pulses with a fractional bandwidth of about 170% and 130% are generated. The switchability of the proposed UWB pulse generator in pulse shape and polarity is also experimentally demonstrated.

UWB monocycle pulse generation by optical polarisation time delay method

A novel method to generate ultra-wideband (UWB) monocycle pulses based on birefringence time delay in polarisation-maintaining fibre (PMF) is proposed and experimentally demonstrated. Two polarity-reverse pulses are generated by polarisation modulation using a single phase modulator. They are delayed in PMF with enough time to generate monocycle pulse.

Ultrawideband monocycle pulse generator with dual resistive loaded shunt stubs

AbstractAn ultrawideband (UWB) monocycle pulse generator with dual resistive loaded shunt stubs is present in this article. The proposed pulse generator consists of a step recovery diode (SRD), a Schottky diode, a pair of resistive loaded stubs, and a pair of short‐circuited stubs. By introducing an additional resistive loaded stub between the SRD and the Schottky diode, the ringing tail of the impulse waveform can be substantially suppressed and the resultant monocycle pulse is well‐behaved with very low ringing level. The measurement result demonstrates a monocycle pulse with peak‐to‐peak amplitude of 550 mV, pulsewidth of 320 ps, ringing level of as low as −22 dB, and good pulse symmetry. This pulse generator is suitable for various UWB applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 459–462, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22145

Optical ultrawideband monocycle pulse generation based on cross-gain modulation in a semiconductor optical amplifier

A novel method for generating ultrawideband (UWB) monocycle pulses based on cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. Thanks to the XGM in the SOA, a pair of polarity-reversed optical Gaussian pulses is generated at the output of the SOA, to which a Gaussian pulse pump and a continuous-wave probe are applied. The two polarity-reversed optical pulses are then time delayed by two cascaded fiber Bragg gratings to introduce a time delay difference. A UWB monocycle pulse with a full width at half-maximum of 48 ps and a fractional bandwidth of 188% is generated at the output of a high-speed photodetector.

On the Development of an Integrated CMOS-Based UWB Tunable-Pulse Transmit Module

A novel low-cost low-power fully integrated tunable transmit module composed of a tunable CMOS monocycle pulse generator and compact uniplanar antenna was designed, built, and tested for ultra-wideband (UWB) impulse systems. The CMOS tunable pulse generator integrates a tuning delay circuit, square-wave generator, impulse-forming circuit, and pulse-shaping circuit in a single chip using a standard low-cost 0.25-mum CMOS process. It can generate a monocycle pulse and Gaussian-type impulse (without the pulse-shaping circuitry) signals with tunable pulse duration. A compact uniplanar UWB antenna was also developed and integrated directly with the CMOS pulse generator chip to form the complete integrated tunable UWB transmit module. Measured results show that the CMOS tunable pulse generator can produce a 0.3-0.6-V peak-to-peak monocycle pulse with 140-350-ps tunable pulse duration and a 0.5-1.3-V peak-to-peak impulse signal with 100-300-ps tunable pulse-duration, and the uniplanar antenna has less than a 18-dB return loss and is suitable for transmitting/receiving UWB time-domain impulse signals covering the entire UWB bandwidth of 3.1-10.6 GHz. Good agreement between measured and calculated performance is also achieved. The UWB transmit module was experimentally characterized and its performance is verified. This UWB module finds applications in various time-domain UWB systems including wireless communications and radar

A 2.4 GHz Differential Wavelet Generator in 0.18 µm Complementary Metal–Oxide–Semiconductor for 1.4 Gbps Ultra-Wideband Impulse Radio in Wireless Inter/Intra-Chip Data Communication

Ultra-wideband impulse based radio systems use Gaussian monocycle pulses as transmitted signals at the transmitting end and as template signals at the receiving end. In this paper we present a new fully integrated differential Gaussian monocycle pulse generator in 0.18 µm complementary metal–oxide–semiconductor (CMOS) technology. Here the Gaussian monocycle pulse is generated from triangular shaped pulse by a single differentiator circuit and it is then converted into differential form by using a single input to dual output amplifier. The developed circuit occupies a small area of 0.06 mm2 and consumes a total power of 44 mW at 1.8 V. The transmission of the generated differential Gaussian monocycle pulse at a rate of 1.4 Gbps through integrated dipole antenna in the same Si-substrate for intrachip communication in future ultralarge scale integrated circuit (ULSI) is verified by simulation and results are presented here.

An Ultrawideband System Architecture for Tag Based Wireless Sensor Networks

With the latest improvements in device size, power consumption, and communications, sensor networks are becoming increasingly more popular. There has also been a great increase in the popularity of commercial applications based on ultrawideband (UWB). Impulse radio (IR) based UWB technology utilizes noise-like signal, has potentially low complexity and low cost, is resistant to severe multipath, and has very good time domain resolution allowing for location and tracking applications. In this paper, the architecture and performance of a noncoherent low complexity UWB impulse radio based transceiver designed for low data rate, low cost sensor network applications is presented. The UWB-IR transmitter is based on a delay locked loop (DLL) and UWB monocycle pulse generator. The UWB-IR receiver utilises a noncoherent, energy detection based approach, which makes it largely independent of the shape of the transmit waveform and robust to multipath channels. The test circuits are designed for 0.35 /spl mu/m SiGe BiCMOS technology. This paper presents system simulations results as well as the performance of key functional blocks of the designed UWB application specific integrated circuit (ASIC) transceiver architecture. The simulated power consumption of UWB-IR transceiver circuits is 136 mW with 100% duty cycle with a 3.3 V power supply.

A new ultra-wideband, ultra-short monocycle pulse generator with reduced ringing

We introduce a new ultra-wideband (UWB), ultra-short, step recovery diode monocycle pulse generator. This pulse generator uses a simple RC high-pass filter as a differentiator to generate the monocycle pulse directly. The pulse-shaping network employs a resistive circuit to achieve UWB matching and substantial removal of the pulse ringing, and rectifying and switching diodes to further suppress the ringing. An ultra-short monocycle pulse of 300-ps pulse duration, -17-dB ringing level, and good symmetry has been demonstrated. Good agreement between the measured and calculated results was achieved.

New uniplanar subnanosecond monocycle pulse generator and transformer for time-domain microwave applications

This paper presents the development of a new monocycle pulse generator and pulse-to-monocycle-pulse transformer operating in the subnanosecond regime. These circuits employ Schottky diodes, step recovery diodes, and simple charging and discharging circuitry, and are completely fabricated using coplanar waveguides. Simple transient analysis and design of the circuits are presented along with their operating principles. The pulse-to-monocycle-pulse transformer converts a 1 V 300 ps pulse into a 0.7-V 350 ps monocycle pulse. The monocycle pulse generator produces a monocycle pulse having 333 ps pulsewidth and more than 2 V from an input square wave of 10 MHz repetition rate. The generated monocycle pulses have very symmetrical positive and negative portions and low ringing level.

Ultrashort Light Pulse Generation with Cerenkov Radiation.

In this paper the generation of ultrashort light pulses with Cerenkov radiation (CR) is reviewed. We discuss the pulse width of CR from a point-charged particle, and introduce a technique of pulse compression using conical and cylindrical gratings. It is shown theoretically that subfemtosecond pulses can be generated with this CR compression technique. To increase the intensity of coherent CR pulses, a bunched pulse electron beam containing a large number of electrons is useful. A system of intense far-infrared monocycle pulse generation from a photoelectron beam pulse is also introduced. This system can be used to generate megawatt, femtosecond pulses.