Zhengguang Xu

An alternative envelope approach for empirical mode decomposition

The paper proposes an alternative envelope approach for empirical mode decomposition. Different from the existing envelope interpolation in the literature available, the new envelope has a simple analytical expression, by which the variations of the extrema in the iterative procedure are investigated in detail to reveal the nature of the sifting process. A comparison of the proposed envelope with the traditional cubic spline interpolation is made in the numerical simulation under a two-tone signal model, which shows that the proposed envelope approach has the fast convergence rate and the higher separation degree in the two-tone signal decomposition.

Identification of Individual Radio Transmitters Based on Selected Surrounding-line Integral Bispectra

A novel method of identifying individual radio transmitters with the same model is proposed in this paper. The selected surrounding-line integral bispectra are utilized as the main feature parameters, and they are interfused with parameters significant for classification of the received signal to form the identification feature vector. A support vector machine (SVM) based on Gaussian core-function is implemented to realize the individual identification. Experimental results demonstrate that the method is able to classify the same model radio transmitter with an accuracy rate under the environment where there is low SNR.

Radio Transmitter Classification using a New Method of Stray Features Analysis Combined with PCA

This paper introduces an efficient technique to design a classifier for identifying radio transmitters with the same model. A new method, square integral bispectra(SIB), is used to extract the unique stray features of individual transmitted signal, and the principal component analysis(PCA) method is utilized further to extract a low-dimensional classification vector. Then,the modulation parameters of individual transmitter significant to classification are combined with the low-dimensional stray features to form a single characteristic feature vector that can effectively represent the target of concern over a broad range of sample data. A support vector machine(SVM) based on Gaussian kernel-function is implemented to realize the individual transmitter classification. The experiments on FSK radio transmitters demonstrate that the suggested technique is highly accurate and robust even in the presence of excessive noise and can solve the problem of identifying individual transmitters with the same model and manufacturing lot.

Individual radio transmitter identification based on spurious modulation characteristics of signal envelop

This paper introduces a novel and efficient technique to identify individual radio transmitters with the same model and manufacturing lot. The spurious modulation characteristic of individual radio transmitted signal is used to reflect the unique stray features of individual transmitters, and fractal dimensions of individual signal envelop are utilized to extract the identification feature vector. The experiments on FM radio transmitters demonstrate that the suggested technique is more accurate than conventional methods such as high-order moments. Also, the new method is computationally efficient and robust in the presence of excessive noise.

On Fourier Interpolation Error for Band-Limited Signals

Fourier interpolation is a useful tool to reconstruct continuous signals from discrete samples. This correspondence derives Fourier interpolation expression from Fourier series for periodic signals and investigates its error expression and upper bound for general band-limited signals. Two numerical examples are given to interpret the meaning of the formulas.

A novel approach for optical minimum shift keying signal generation

A novel approach for the generation of optical minimum shift keying (MSK) signals is presented. The transmitter is based on merely one phase modulator (PM), which is driven by a phase controller. The receiver uses direct detection based on the Mach-Zehnder delay interferometer (MZI) and optical balanced receiver. In this paper, firstly the detailed principle on optical MSK generation and detection is derived and analyzed. Then, 40Gb/s optical MSK signal based on this scheme is successfully generated and transmitted over several fiber links (SMF+DCF) with only the first order dispersion compensation. Finally, the performance of the MSK based on PM is compared with that of the MSK based on other two known schemes, in terms of waveform, phase and spectrum. Simulation results show that not only this approach has a simpler architecture for the optical MSK transmitter, and but also the optical MSK generated has better performance.

Non-data-aided timing recovery scheme for MSK signals

This paper analyzes the signal decomposition expression for Minimum Shift Keying (MSK) signals. The Phase of MSK signal with real parts and imaginary parts is recovered from discrete-Fourier-transform of signal appropriate parts, and then Phase is translated into time. Based on this, a non-data-aided timing recovery is proposed for MSK signals by absolute algorithm. Compared with the existing algorithm, the proposed scheme is more superior in performance and is close to Modified Cramer-Rao Bound (MCRB).

A robust timing recovery algorithm with frequency offset for MIL-STD SOQPSK

A robust timing recovery algorithm for military standard (MIL-STD) shaped-offset quadrature phase-shift keying (SOQPSK) is presented and this scheme can be used in the signal with frequency offset. The new algorithm is based on the correlation calculation, and the timing offset information is extracted by the absolution operation to the correlation function. The theoretical analysis and the simulation result both show that the provided scheme can work well to the MIL-STD SOQPSK signal with frequency offset.

Performance of DP-QDQ compared with DP-16QAM, DP-64QAM and DP-256QAM

DP-QDQ is a partial-response shaping modulation based on 16QAM, which has been proposed in our previous research paper. In this paper, the power spectral density (PSD) of the DP-QDQ signal is analyzed and compared with DP-16QAM, DP-64QAM, and DP-256QAM signals, and the simulation setup is presented. The analysis results show the DP-QDQ signal has high spectral efficiency. In addition, the optical coherent DP-QDQ system is discussed in compared with DP-16QAM, DP-64QAM, and DP-256QAM systems in terms of the tolerance to optical signal to noise ratio (OSNR), transmission distance at 100G/s by simulations. It is revealed that DP-QDQ not only achieves high spectral efficiency, but also obtains a good compromise of the performances on spectral efficiency, OSNR tolerance and transmission distance.

Optical CPFSK with an arbitrary modulation index

This paper proposes an optical continuous-phase frequency shift keying (CPFSK) modulation scheme with an arbitrary modulation index. Simulations on the performances of CPFSK and differential phase shift keying (DPSK) show that CPFSK of modulation index is 2/3 performs best on receiver sensitivity, dispersion penalty and nonlinearity in the balanced receiving system of 40G.