In this letter, we propose dual-mode chirp spread spectrum (DM-CSS) modulation for low-power wide-area networks. DM-CSS is capable of achieving a higher spectral efficiency (SE) relative to its counterparts, such as Long Range (LoRa) modulation. Considering the same symbol period, SE in are augmented by: (i) simultaneously multiplexing even and odd signals; (ii) using phase shifts 0 <inline-for...

We consider a multicarrier chirp-based waveform for joint radar and communication (JRC) systems derive its time discrete periodic ambiguity function (AF). A set of parameters (e.g., chirp rate) can together with the transmit sequence be selected to shape AF thumbtack-like, or ridge-like, either along delay axis Doppler axis. demonstrate how these shapes are applicable different use cases, e.g.,...

Nyquist folding receiver (NYFR) is a novel ultra-wideband receiver architecture which can realize wideband receiving with a small amount of equipment. Linear frequency modulated/binary phase shift keying (LFM/BPSK) hybrid modulated signal is a novel kind of low probability interception signal with wide bandwidth. The NYFR is an effective architecture to intercept the LFM/BPSK signal and the LFM...

Discussions about the evolution of female mating preferences have often suggested that females should express multiple strong preferences when different male traits are correlated with different mating benefits, yet few studies have directly tested this hypothesis by comparing the strength of female preferences for male traits known to be correlated with different benefits. In the variable fiel...

A review of multichannel long integration time, optical Fourier transform techniques for advanced Fourier spectroscopy systems is followed by the description of a new multichannel time-integrating optical Fourier transform chirp-Z system and a discussion of its use in Fourier spectroscopy signal processing.

The traditional approach of improving radar range resolution using a linear frequency modulated chirp signal requires the full width of the frequency spectrum, which is not feasible in the UHF band due to interference or frequency allocation for other purposes. In this study a linear frequency modulated chirp signal is approximated using two stepped-frequency pulse train waveforms, a continuous...

The problem of the parameter estimation of chirp signals is addressed. Several closely related estimators are proposed whose main characteristics are simplicity, accuracy, and ease of on-line or off-line implementation. For moderately high signal-to-noise ratios they are unbiased and attain the Cramer-Rao bound. Monte Carlo simulations verify the expected performance of the estimators.

In this paper, we show that there are a number of uncertainty principles for the local polynomial Fourier transform and local polynomial periodogram. Systematic analysis of uncertainty principles is given, explicit expressions of the uncertainty relations are derived, and an example using the chirp signal and the Gaussian window function is given to verify the expressions.

Optical signal processing can be done with time-lens devices. A temporal processor based on chirp-z transformers is suggested. This configuration is more compact than a conventional 4-ƒ temporal processor. On the basis of implementation aspects of such a temporal processor, we did a performance analysis. This analysis leads to the conclusion that an ultrafast optical temporal processor can be i...

This paper introduces a novel algorithm to excise single and multicomponent chirp-like interferences in direct sequence spread spectrum (DSSS) communications. The excision algorithm consists of two stages: adaptive signal decomposition stage and directional element detection stage based on the Hough-Radon transform (HRT). Initially, the received spread spectrum signal is decomposed into its tim...