In this paper, we develop some methods to save the bandwidth required in the fractional domain. The fractional domain is the transformed domain of the fractional Fourier transform (FRFT). It is the intermediate of the time domain and the frequency domain. We find that, with the aid of the fractional Hilbert transform and other techniques, we can save 112 or 314 of the bandwidth in the fractiona...

A computationally eecient and accurate frequency estimation and tracking algorithm is proposed, based on the Adaptive Frequency Estimator (AFE) of Etter and Hush. A Lagrange interpolator (a fractional delay lter) is used to estimate the gradient of the performance surface of the adaptation, which enables highly accurate estimation. The performance of the new algorithm is demonstrated in the con...

An analysis of a discrete time-frequency distribution yields a new periodic wide band probing signal for use in unknown system identiication. The derivation is based on mathematical properties of the discrete Wigner distribution. Like the continuous distribution, the discrete version also sat-isses the covariance property, meaning transformations in the time-frequency plane are equivalent to tr...

Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date. Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present ...

In this paper a new time-frequency interference terms cancellation method will be presented. We will consider this problem in the multi-structure signal case, where this problem is often difficult to solve due to interference geometry, which can be superposed on the signal component. We propose a technique based on the atomic decomposition of the signal, in order to extract its components. A py...

Linear chirps, a special case of polynomial phase exponentials, have recently been proposed for digital watermarking. In this work, we propose a known-host-state methodology for designing image watermarks that are robust to compression. We use a two-dimensional frequencymodulated chirp as a spreading function in a block-based spatial watermarking scheme. In each block, the chirp is used to embe...

A moving target will cause changes in the chirp signal coefficients of signals received by synthetic aperture radar (SAR). By computing these coefficients, we can find the speed of a moving target speed. This paper describes a new approach for estimating the doppler coefficients. The approach uses the sub-aperture interferometry scheme to estimate the chirp signal coefficients. A closed-form ex...

In situations where the presence of a signal is to be detected in several noisy channels, often one channel will have higher signal-to-noise ratio (SNR) than the others. When the SNR on one channel is sufficiently high that the signal can be extracted from that channel, it may be possible to use the extracted signal to aid in detecting the presence of the signal on the other channels. In this p...

The design study of an FEL oscillator with a bandwidth of Aw/wo < 10has been carried out. In this conceptual design, a grating rhomb is used to suppress the sideband instability. The spectral evolution of the FEL has been simulated using a one-dimensional, time-dependent FEL code. The system parameters for the simulations are: electron beam energy 120MeV, current I = 50A, electron micropulse le...

Automatic Digital signal type classification (ADSTC) has many important applications in both of the civilian and military domains. Most of the proposed classifiers can only recognize a few types of digital signals. This paper presents a novel technique that deals with the classification of multi-user chirp modulation signals. In this paper, the peak of the bispectrum and its bi-frequencies are ...