Multipath propagation causes the transmitted signal to take numerous, time-varying different-length paths to receiver. Exploitation of conventional frequency-constant carrier signals for communication over underwater acoustic channels typically shows that intricate mutual time variations of multipath arrivals create a serious problem for equalizers to compensate for non-stable interferences. Co...

Interrupted-sampling repeater modulation (ISRM) can generate multiple virtual target images by sampling and forwarding radar signals to confront the inverse synthetic aperture (ISAR). However, repeating delay is unavoidable system complex. Moreover, numerous works mainly discuss ISAR image deception based on periodic modulation, effect relatively limited. Active frequency selective surface (AFS...

This paper considers the model problem of recovering a signal f(t) from noisy sampled measurements. The objects we wish to recover are chirps which are neither smoothly varying nor stationary but rather, which exhibit rapid oscillations and rapid changes in their frequency content. We introduce a mathematical model to describe classes of chirps of the general form f(t) = A(t) cos(λφ(t)) where λ...

This article considers locating a noncooperative underwater transmitter utilizing multiple receivers, such that each receiver can measure the frequency difference of arrival (FDOA) as well time (TDOA) transmitter’s sound. case where unknown emission changes goes. addresses hybrid TDOA-FDOA localization, under assumption maximum speed is known in advance. To best our knowledge, this unique tackl...

The application of informative frequency band identification methods makes it possible to enhance weak damage components in the vibration signals acquired from rotating machines. Some machines (e.g. wind turbines) operate inherently under time-varying operating conditions, however, very few have been developed with varying conditions mind. Therefore, this work, a systematic framework for obtain...