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We present a novel timing recovery scheme based on a Gardner phase detector performing excellently in spectrally efficient Nyquist coherent optical systems. Good clock tone performance is obtained for QAM modulation formats and roll-off factor (ROF) values close to 0.
Using a highly efficient (74%) PPKTP source of narrowband polarization entangled photon pairs (as measured with TES detectors) together with a fast polarization modulator (11 ns) we should be capable of a loophole free Bell test.
For wireless applications, an OFDM-based system can be of interest because it gives greater immunity to impulse noise, multi-path fading and eliminates necessity of equalizers. High PAPR is one of the critical problems in OFDM modulation. There are large numbers of techniques for reduction of PAPR. Selections of any method depend on PAPR Reduction performance, Data Rate loss and transmit signal power...
This work examines the idea of dislocating the carrier transmission from the tag-modulated carrier reception, i.e. bi-static rather than mono-static backscatter radio. In that way, more than one carrier transmitters can be distributed in a given geographical area and illuminate a set of RF tags/sensors that modulate and scatter the received carrier towards a single software-defined receiver. The increased...
This paper proposes a simple multi-cycle cyclostationary based signal detection (spectrum sensing) algorithm for Orthogonal Frequency Division Multiplexed (OFDM) signals in cognitive radio networks. We assume that the noise samples are independent and identically distributed (i.i.d) random variables all with unknown (imperfect) variance. Our detection algorithm employ the following three steps. First,...
Gaussian minimum shift keying (GMSK) is known to be a bandwidth efficient modulation scheme. In this paper we introduce the quadrature multiplexed GMSK (QM-GMSK) which improves GMSK's bandwidth efficiency further. A coherent orthogonal detector is presented to achieve a bit error performance comparable to that of coherent FSK.
Presented in this paper are the specific conducted EMI related issues accompanying the application of Power Electronic Interfaces (PEI) in Smart Grids such as the flow of EMI currents in extensive circuits and aggregation of the interferences introduced. Compensation of the voltage interference sources inside of the converters has been recommended as suitable side effects mitigating technique.
Multi-h continuous-phase modulation (CPM) has been used in telecommunication and aeronautical telemetry system due to its high power and spectral efficiency. Nonetheless, the optimum MLSE receiver suffers from high implementation complexity. One-symbol differential trellis detector with Viterbi algorithm for multi-h CPM signal is proposed in this article, we derives a simple trellis to reduce the...
This paper presents the channel capacity and capacity-achieving input distribution of an energy detection receiver structure. A proper statistical model is introduced which makes it possible to treat the energy detector as a constrained continuous communication channel. To solve this non-linear optimization we used the Blahut-Arimoto algorithm extended with a particle method, so that also continuous...
Recently, a turbo-coded noncoherent space-time modulation scheme, which is aimed at providing both a high data transmission rate and a low receiving complexity, was proposed for noncoherent block fading channels. However, in cases where a large number of transmit antennas exist, the turbo code does not match well with the noncoherent space-time modulation scheme, and results in performance degradation...
Recently, the concept of the cooperative communications has been applied extensively for the ultra-wideband (UWB) system. In this paper, the cooperative scheme of the noncoherent UWB impulse radio system with block-coded modulation (BCM) having a codeword matching and signal aggregation (CMSA) detection is discussed under different fading environments, which has not been studied yet. To enlarge the...
In Fourier transform spectroscopy, there is a wave distortion of the optical system, and it has a greater impact on the data obtained by equipment. With analysis for the basic principle of the Fourier transform spectroscopy, we give the interferogram mathematical model of wave distortion. By using this model and the computer simulation method, we simulate with the distortion value 60nm, give the recovery...
This paper presents a new iterative multiuser (MU) detection algorithm for asynchronous spectrally-efficient continuous-phase modulation in additive white Gaussian noise. The proposed detector is derived from the sum-product (SP) algorithm and the factor graph (FG) framework, and performs approximate maximum a posteriori bit detection. A convenient FG of the actual MU detection problem is considered,...
A cognitive radio should be able to detect unused spectrum band and to change its transmission parameters in order to transmit within these free bands. To achieve this, reliable detection of incumbent signals as well as of other opportunistic signals that are using the said spectrum, is necessary. Generalized Frequency Division Multiplexing (GFDM) is a recent multicarrier modulation technique with...
The purposes of this paper are to present a new user-friendly software package intended for evaluating the performance of dental digital radiography systems, and to study the effect of the radiation dose on the resolution and noise properties of photo-stimulable-phosphor-layer (PSPL) detectors. The modulation transfer function (MTF) was measured using the edge method and the noise power spectrum (NPS)...
We investigate non-coherent FH/BFSK detection in band multitone jamming when Bayesian detection is unfeasible due to lack of knowledge on a priori jamming state probabilities. We derive joint-suboptimal decision metrics of jamming states under Minimax hypothesis testing in band multitone jamming and AWGN. A sub-optimal generalized likelihood ratio test is also explored. Simulation results demonstrate...
We investigate modulation and coding techniques that approach the fundamental limits of communication and key distribution over optical channels, in the regime of simultaneously high photon and bandwidth efficiencies. First, we develop a simple and robust system design for free-space optical communication that incorporates pulse-position modulation (PPM) over multiple spatial degrees of freedom in...
By combing ultra-fast photonic-transmitter-mixers and envelop detectors with record-high modulation (26 GHz) and video bandwidths (37 GHz), respectively, error-free on-off-keying wireless transmission at W-band with data rate as high as 25 Gbit/sec can be achieved.
Cone-beam CT has a lot of advantages such as short time reconstruction, high spatial resolution, broad irradiation and computational efficiency and so on. However, because of large area of irradiation, cone-beam CT data may process very high scatter-to-primary ratios (SPR>2), which will result in severe cupping artifacts, streaks and CT number inaccuracies in reconstructed images. It remains difficult...
Integrating optical interconnects into the next-generation multi-/many-core architecture has been considered a viable solution to addressing the limitations in throughput, latency, and power efficiency of electrical interconnects. Optical interconnects also allow the performance growth of inter-core connectivity to keep pace with the growth of the cores' processing ability. However, variations in...
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