Mobile communication system uses Quadrature Phase Shift Keying (QPSK) as one of the efficient digital modulation techniques. Pulse-shaping technique plays an important role in digital transmission. Root-Raised Cosine (RRC) and Raised Cosine (RC) filters are two important pulse-shaping filters used in mobile communication system. In this paper we have presented the study of some useful parameter...

We propose a locomotion technique for a legged robot that is high-centered, i.e., a robot stuck on a block with its legs dangling in air. By using its legs as reaction masses, the robot might be able to rock and roll on its stomach and incrementally move forward off the block, a form of legless locomotion using halteres. With locomotion of high-centered robots using body attitude oscillations a...

Chorin's vortex blob method has been proposed as a way to extend vortex sheet motion past the singularity formation time, into the physically important roll-up regime. Basic questions are: 1. Does the vortex blob method converge to an infinite spiral as the smoothing parameter tends to zero? 2. Do vortex blob computations approximate real fluid motion? This paper will present and discuss three ...

In this paper, a robust tracking control method for automatic take-off and trajectory tracking of a quadrotor helicopter is presented. The designed controller includes two parts: a position controller and an attitude controller. The attitude controller is designed by using the sliding mode control (SMC) method to track the desired pitch and roll angles, which are the output of position controll...

Organic light emitters based on multiresonance-induced thermally activated delayed fluorescent materials have great potential for realizing efficient, narrowband organic light-emitting diodes (OLEDs). However, at high brightness operation, efficiency roll-off attributed to the slow reverse intersystem crossing (RISC) process hinders use of in practical applications. Here we report a heavy-atom ...

Good tracking requires that the quintessence energy fraction slowly increase while the roll λ ≡ −d lnV/κdφ slowly decreases, but is not yet truly slow-rolling. The supernova bound on the present quintessence equation of state requires either (1) a cosmological constant or other finetuned ”crawling quintessence” or (2) ”roll-over quintessence” that tracked until recently, but now became slow rol...

We report a large aperture PPMgLN based OPO generating 21W of average output power at a slope efficiency of 45%, pumped by the output from a polarization maintaining Ytterbium doped fiber MOPA operating at 1060nm producing 58W of average output power and 20ns pulses at a repetition rate of 100kHz. A maximum of 5.5W of optical power was recorded at the idler wavelength of 3.82μm without thermal ...

We demonstrate a novel wavelength-comb-swept laser based on two intra-cavity filters: an acousto-optic tunable filter (AOTF) and a Fabry-Pérot etalon filter. The AOTF is used for the tunable selection of the output wavelength with time and the etalon filter for the narrowing of the spectral linewidth to extend the coherence length. Compared to the conventional wavelength-swept laser, the acoust...

An effective technique to design compact low pass filter has been proposed in this paper. The proposed method is highly effective for L-band applications. Low impedance microstrip lines are arranged such that they work as open stubs to increase the selectivity of the filter. Using the proposed technique about 57% size reduction has been realized with sharper roll off characteristics. An empiric...

Interpolators have found widespread applications in communication systems such as multimedia. In this paper, the interpolated timing recovery employing raised cosine pulse for digital magnetic recording channel is investigated. This study indicates that the raised cosine interpolator with rolloff factor β between 0.4 and 0.6 is shown to have less aliasing effect and achieve better MSE performan...