Coded modulation is a bandwidth efficient schemes that combines the function of coding and modulation. In this paper a comparative study of various modulation techniques such as Trellis coded modulation(TCM),Turbo Trellis coded modulation(TTCM),Bit-Interleaved Coded Modulation(BICM) ,Iterative Decoding Bit-Interleaved Coded Modulation(BICM-ID) and Superposistion Coded Modulation schemes over Ga...

A modulated holding beam shining a VCSEL above threshold can improve modulation bandwidth by adjusting the semiconductor laser’s relaxation oscillation frequency. The improved modulation characteristics are accompanied by reduced damping rate. By choosing correct parameters, dynamical behavior of system and cavity solitons is changed.

Abstract For pulse compression characteristics and not easily affected by noise, linear frequency modulation signal are widely used in underwater acoustic communication. This paper analyzes the characteristics of hyperbolic frequency modulation signal over underwater acoustic channels. Compared with linear frequency modulation signal, hyperbolic frequency modulation has the same performance of ...

This report presents the need for embedded multiresolution (MR) modulation, specifically in broadcast scenarios. Existing modulation schemes, based on MR-QAM, are not bandwidth-efficient. Efficient layered or multiresolution data transmission over bandwidth-efficient CPFSK modulation scheme has been proposed. Superiority of the proposed embedded multiresolution CPFSK (MRCPFSK) over existing met...

the modulation response, relative intensity noise and frequency noise characteristics of qd lasers are investigated theoretically, in presence of an additional optical pumping. it is revealed that the modulation response of qd laser enhances under additional optical beam. by small signal analysis of the carriers' and photons' rates, it is proposed that by injecting excess carriers to ...

This paper proposes the virtual flux based direct power control for Vienna rectifier. No need for the input voltage sensors, the current regulation loop and PWM voltage modulation block along with the active and reactive power decoupling are some of the salient advantages of this method that make it suitable for controlling the conventional active rectifiers. However, due to the three-level nat...

In this work the performance of a wavelength division multiple access (WDMA) system with direct detection receiver is investigated. For this purpose, the probability of error in a WDMA network with OOK modulation considering crosstalk, ISI, photo detector noise and thermal noise is calculated and the effect of each on system performance is investigated. The system performance in presence of PIN...

The present endeavor is meant (a) to provide a direct comparison between first- and second-order temporal modulation and, by so doing, (b) to eliminate all spatial clues that might have contaminated previous assessments of the second-order temporal modulation transfer function (TMTF). The second aim was achieved by means of the temporal modulation of a purely temporal white noise, a stimulus us...

In this paper, we present new dynamic features derived from the modulation spectrum of the cepstral trajectories of the speech signal. Cepstral trajectories are projected over the basis of sines and cosines yielding the cepstral modulation frequency response of the speech signal. We show that the different sines and cosines basis vectors select different modulation frequencies, whereas, the fre...