The nonlinear dynamic behavior of a direct frequency-modulated diode laser with strong optical feedback is examined and compared to a laser diode subject to electro-optically modulated, strong optical feedback. Direct modulation is achieved by sinusoidal modulation of the diode laser injection current. Electro-optic modulation is achieved by applying a sinusoidal voltage to an intracavity phase...

this paper presents a novel control method to improve the efficiency of low-voltage dc-dc converters at light loads. pulse width modulation (pwm) converters have poor efficiencies at light loads, while pulse frequency modulation (pfm) control is more efficient for the same cases. switching losses constitute a major portion of the total power loss at light loads. to decrease the switching losses...

With more and more developments in wireless communication, spread spectrum modulation techniques have been widely used in various modulation systems. Frequency hopping technique is one of the types of spread spectrum system. In this paper, frequency hopping techniques are compared in a DBPSK modulation system which employs non coherent reception. Fast frequency hopping and multicarrier frequenc...

For high-frequency sinusoidal carriers, the threshold for detecting sinusoidal amplitude modulation increases when the signal modulation frequency increases above about 120 Hz. Using the concept of a modulation filter bank, this effect might be explained by (1) a decreasing sensitivity or greater internal noise for modulation filters with center frequencies above 120 Hz; and (2) a limited span ...

The parameter estimation of the frequency agility (FA) signal using the coding Nyquist folding receiver (CNYFR) is presented. The estimation algorithm adopting linear frequency modulation (LFM) as the local analogue modulation is derived. The Nyquist zone is estimated by the pseudo Wigner-Ville distribution (PWVD) and the hopping frequencies are calculated by the maximum likelihood (ML) method....

This paper proposes a Flexible Power Electronic Transformer (FPET) for the application in the micro-grids. The low frequency transformer is usually used at the Point of Common Coupling (PCC) to connect the low voltage grid and utility network to each other. The conventional 50Hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. In this pap...

introduction: the nucleus paragigantocellularis lateralis (lpgi) is involved in the descending pain modulation. the neurostreoid, 17β-estradiol found in the pgi nucleus and modulates nociception by binding to estrogen receptors and also by allosteric interaction with nmda receptors. in this study, the role of nmda receptors in the 17β-estradiol-induced pain modulation was investigated by assess...

In this contribution, we consider the effect of a carrier frequency offset on the performance of MC-CDMA and MC-DS-CDMA, which are both a combination of the multicarrier transmission technique and the CDMA multiple access technique. We show that both systems strongly degrade in the presence of a carrier frequency offset. Furthermore, we show that, for given spreading factor, the MC-DS-CDMA syst...