In this paper the mode-locking of an erbium-doped fiber ring laser with frequency shifted feedback is described. We use the configuration with an acousto-optical modulator inserted in the laser cavity that produces 1.7 ps pulses with a 40 MHz repetition frequency. The corresponding optical frequency comb has a bandwidth of more than 10 nm, centered at 1558 nm. The laser operates with external i...

To signal processing precision of parametric sound source, the theoretical formula is derived in this paper used to calculate self-demodulated signal when dual-frequency signals taken as input of parametric sound source. And some experiments are done to verify the derived formula. This paper analyzes mainly the influences of amplitude changes of input signal frequency components on sound pressu...

Traditional lumped small signal equivalent circuit models of AlGaN/GaN metal oxide semiconductor high electron mobility transistors (MOS-HEMTs) are made up constant valued elements. Such unable to capture the frequency behavior (above 20 GHz) device. In this work, a modified model MOS-HEMTs is presented. The key feature proposed that values different elements in considered be dependent nature a...

A dual-ring injection-locked fiber laser consisting of a ring of optoelectronic oscillator (OEO) and a ring of fiber laser is proposed and demonstrated for tunable millimeter-wave (mm-wave) generation. The approach combines the advantages of mm-wave generation based on OEOs and fiber lasers, which can generate a high-frequency, low-phase-noise, and a mode-hopping-free mm-wave signal with a larg...

This study focuses on investigation of the method of identifying injector faults in a JCB 444T2 diesel engine using acoustic emission (AE) technique. Different kinds of injector faults were seeded in the four-cylinder, four-stroke, and turbo-engine. Then, faulty injectors are tested to evaluate AE based injection fault detection. The AE signals recorded from the tests were processed in the angu...

A novel optical millimeter-wave generation using sideband injection locking is demonstrated using monolithic two-section DFB lasers. The tunable millimeter-wave is generated by adjusting the RF-modulation frequency and bias currents. Summary The optical generation of millimeter-wave has been demonstrated and attracted much attention because of its flexibility and applicability in broadband mobi...

We have developed the effective algorithm for detecting digital binary phase-shift keyed signals. This algorithm requires a small number of arithmetic operations over the signal period. It can be relatively easy implemented based on the modern programmable logic devices. It also provides high interference immunity by identifying signal presence when signal-to-noise ratio is much less that its w...