In recent years there has been a renewed interest in finding fast algorithms to compute accurately the linear canonical transform (LCT) of a given function. This is driven by the large number of applications of the LCT in optics and signal processing. The well-known integral transforms: Fourier, fractional Fourier, bilateral Laplace and Fresnel transforms are special cases of the LCT. In this p...

This paper presents a novel signal-processing-based artificial model of the auditory mechanism. This work is inspired by the psychocortical fact that the biological cochlea is very sensitive to frequency-varying tones, or chirps. The method uses a novel combination of several (at least three) Harmonic-Chirp transform instances, that project the time–frequency energy on different views; all proj...

The Fractional Fourier Transform is a generalized form of Fourier Transform, which can be interpreted as a rotation by angle ? in time-frequency plane or decomposition of signals in terms of chirps. However it fails in locating Fractional Fourier Domain Frequency contents. Short-time FRFT variants are suitable for analysis of multicomponent and non-linear chirp signals with improved time-freque...

Spectrogram analysis frequently suffers from inadequate time or frequency resolution, respectively. However, time-frequency reassigned spectrograms offer an attractive extension regarding the resolution trade-off. Specifically, this method deduces an improved time-frequency localization from the derivatives of the spectrogram phase, with respect to time and frequency. For high-quality images of...

In this paper Adaptive filter is designed and simulated using different algorithms for noise reduction in different signals. The developed filter has been analyzed using Least Mean Square (LMS), Normalized Least Mean Square (NLMS) and Recursive Least Squares (RLS) algorithms for sinusoidal, chirp and saw-tooth signals. The performance of developed filter has been compared interms of Rate of Con...

We have developed and demonstrated 3D imaging for contraband detection using a submillimeter-wave frequency modulated continuous wave (FMCW) radar with a fast microwave chirp and phase coherent detection. The technique provides an important advantage over more traditional CW RF imaging because of the ability to time-gate the return signals. This can be used to discern specific objects by greatl...

The responses of neurons to natural sounds and simplified natural sounds were recorded in the primary auditory cortex (AI) of halothane-anesthetized cats. Bird chirps were used as the base natural stimuli. They were first presented within the original acoustic context (at least 250 msec of sounds before and after each chirp). The first simplification step consisted of extracting a short segment...

Long-time coherent integration works to significantly increase the detection probability for maneuvering targets. However, during observation time, problems that often tend occur are range cell migration (RCM) and Doppler frequency (DFCM), due high velocity acceleration of target, which can reduce In this regard, we propose a new approach, based on product scale zoom discrete chirp Fourier tran...

Rapid acquisition by sequential excitation and refocusing (RASER) is a new ultrafast MRI technique (1). It provides single-shot images that are purely T2-weighted, so there are no artifacts due to T2 * effects that plague EPI. RASER shows promise for fMRI studies in areas of the brain that are difficult to image with EPI (2, 3). The basis of RASER is time-encoding, which uses a frequency-swept ...

We introduce a new family of (2+1)D light beams with pre-engineered abruptly autofocusing properties. These beams have a circularly symmetric input profile that develops outward of a dark disk and oscillates radially as a sublinear-chirp signal, creating a series of concentric intensity rings with gradually decreasing width. The light rays involved in this process form a caustic surface of revo...