Long-range (LoRa) communication has attracted much attention recently due to its utility for many Internet of Things applications. However, one the key problems LoRa technology is that it vulnerable noise/interference use only up-chirp signals during modulation. In this paper, solve problem, unlike conventional modulation scheme, we propose a scheme based on joint up- and down-chirps. A fast Fo...

Chirp Signal, a finite duration pulse with Linear Frequency Modulation (LFM) is the signal waveform widely used for coherent image formation. Coherent imagery is derived essentially as a 2-dimensional correlation of received, delayed chirp waveform with a 2dimensional matched filter. There is wide and active research interest in analyzing coherent imagery at multiple scales for multiresolution ...

Recently, a direct method of the time–frequency approach, called signal separation operator (SSO), which is based on sinusoidal approximation, was introduced to solving inverse problem multicomponent separation. In very recent paper “Direct via extraction local frequencies with adaptive time-varying parameters”, authors obtained more accurate component recovery formula derived from linear chirp...

The chirp function is one of the most fundamental functions in nature. Many natural events, for example, most signals encountered in seismology and the signals in radar systems, can be modeled as the superposition of short-lived chirp functions. Hence, the chirp-based signal representation, such as the Gaussian chirplet decomposition, has been an active research area in the field of signal proc...

The time-frequency (TF) filter design of non-stationary signals such as chirp signals are studied in the fractional domain. The designed TF/ Adaptive linear time variant (ALTV) filter is implemented as a nonoverlapping Fractional Fourier transform (FRFT). Using FRFT the adaptive filter is converted into mathematical form to be included in different methods for detecting the presence of a multi ...

This article demonstrates the measurement of shear wave speed and shear speed dispersion of biomaterials using a chirp signal that launches waves over a range of frequencies. A biomaterial is vibrated by two vibration sources that generate shear waves inside the medium, which is scanned by an ultrasound imaging system. Doppler processing of the acquired signal produces an image of the square of...

1 2 Abstract The spectrum of Single Mode Laser pulses generated by fast Pseudo Random Word Modulation is studied numerically for Return-to-Zero and Non-Return-to-Zero control signals. We analyze both statistics and the worst cases for the frequency chirp during each optical pulse, and we study the connection between these frequency chirps and the turn-on times. We show that patterns in the modu...

We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functio...

The linear canonical transform (the LCT) is a useful tool for optical system analysis and signal processing. It is parameterized by a 2 2 matrix . Many operations, such as the Fourier transform (FT), fractional Fourier transform (FRFT), Fresnel transform, and scaling operations are all the special cases of the LCT. In this paper, we will discuss the eigenfunctions of the LCT. The eigenfunctions...

Male signals that provide information to females about mating benefits are often of low reliability. It is thus not clear why females often express strong signal preferences. We tested the hypothesis that females can distinguish between males with preferred signals that provide lower and higher quality direct benefits. In the field cricket, Gryllus lineaticeps, females usually prefer higher mal...