One fundamental issue in designing a good radar system is it’s capability to resolve two small targets that are located at long range with very small separation between them. Pulse compression techniques are used in radar systems to avail the benefits of large range detection capability of long duration pulse and high range resolution capability of short duration pulse. In these techniques a lo...

The properties of ultrashort gaussian pulse propagation in a dispersive, attenuative medium are reviewed with emphasis on the pulse velocity. Of particular interest is the group velocity whose physical interpretation loses meaning in causally dispersive materials as the temporal pulse width decreases into the ultrashort pulse regime. A generalized definition of the group velocity that applies t...

In typical chirped pulse amplification (CPA) laser systems, scanning the grating separation in the optical compressor causes the well know generation of linear chirp of frequency vs. time in a laser pulse, as well as a modification of all the higher order phase terms. By setting the compressor angle slightly different from the optimum value to generate the shortest pulse, a typical scan around ...

The problems in Harold Walker’s latest essay, amusingly titled “The Facts of Life”, start with his very first line: Digital Modulation is usually a form of pulse modulation, of which, there are two types-Pulse Width and Pulse position. What about pulse amplitude modulation (PAM), phase shift keying (PSK) and frequency shift keying (FSK), just to mention a few others? All pulses are analyzed by ...

Marx modulators operated by solid-state switches (e.g. MOSFET, IGBT) offer an alternative to traditional high voltage (HV) modulators for rf power sources. They have the merits of compact size, high-energy efficiency, high reliability, pulse width control and cost reduction. However, Marx modulators need a complex voltage compensation circuit if they are employed in long pulse applications such...

In this paper, a 7-level Diode Clamped Multilevel Inverter (DCMLI) is simulated with three different carrier PWM techniques. Here, Carrier based Sinusoidal Pulse Width Modulation (SPWM), Third Harmonic Injected Pulse Width Modulation (THIPWM) and Modified Carrier-Based Space Vector Pulse Width Modulation (SVPWM) are used as modulation strategies. These modulation strategies include Phase Dispos...

We introduce and experimentally validate a pulse picking technique based on a travelling-wave-type acousto-optic modulator (AOM) having the AOM carrier frequency synchronized to the repetition rate of the original pulse train. As a consequence, the phase noise characteristic of the original pulse train is largely preserved, rendering this technique suitable for applications requiring carrier-en...

The numerical modeling of actively Q-switched fiber lasers is systematically presented. On the basis of typical Q-switched ytterbium-doped double-clad fiber lasers under forward and backward pump, the dynamic characteristics of pulse energy, pulse width, population inversion, and stored energy at tens-of-kilohertz repetition rates are studied by using the traveling-wave method. The laser perfor...

This paper proposed the comparison made between Multi-Carrier Pulse Width Modulation, Sinusoidal Pulse Width Modulation and Selective Harmonic Elimination Pulse Width Modulation technique for minimization of Total Harmonic Distortion in Cascaded H-Bridge Multi-Level Inverter. In Multicarrier Pulse Width Modulation method by using Alternate Position of Disposition scheme for switching pulse gene...

A real-time eye diagram monitoring method for optical signals is proposed and experimentally demonstrated based on sampling. In the system, under test are directly sampled by an sampling pulse train with a narrow width high repetition frequency. The achieved in Mach-Zehnder modulator (MZM), gated on-off electrical pulse. then broadened detected photodetector (PD). low-speed analog-to-digital co...