Chirp signals play an important role in the statistical signal processing. Recently Kundu and Nandi [8] derived the asymptotic properties of the least squares estimators of the unknown parameters of the chirp signals model in presence of stationary noise. Unfortunately they did not discuss any estimation procedures. In this article we propose a computationally efficient algorithm for estimating...

During application of high intensity focused ultrasound (HIFU) with therapy arrays, the existence of grating lobes can cause heating at unintended tissue regions. Therefore, the reduction of grating lobes in therapeutic arrays is an important goal. One way to reduce the grating lobes in therapy arrays is to excite the arrays with broadband signals (defined here as >10% fractional bandwidth). To...

In the paper, new and easy-to-compute closedform expressions for average symbol error probability of digital M -ary chirp communication system impaired by additive white Gaussian noise and fading are derived. Three fading environments, Rayleigh, Nakagami-m, and generalized-K, that represent most practical wireless channels are considered. The closed-form expressions derived are then used to ill...

For the chirp rate and its change rate estimation of cubic phase signal (CPS), conventional algorithms cannot achieve a trade-off between low computational cost and high performance. In this paper, by utilizing the numerical computational method (NCM), effects of Doppler frequency shift are quantified, and the relationships of the optimal signal length with the chirp rate and change rate of chi...

A chirp spread spectrum (CSS) transceiver architecture for IEEE 802.15.4a is proposed and implemented. In the transmitter, the size of the read-only memory that stores CSS signal samples for the chirp modulator is reduced by removing duplicate samples among subchirps. In the receiver, a matched filter is utilized to remove the other band noise caused by the band hopping property of CSS. A robus...

We present a new method of beamforming using the fractional Fourier transform (FrFT). This method encompasses the conventional minimum mean-squared error (MSE) beamforming in the frequency domain or spatial domain as special cases. It is especially useful for applications involving chirp signals such as signal enhancement problems with accelerating sinusoidal sources where the Doppler effect ge...

In this paper, we propose the use of ‘chirp coding’ for embedding a watermark in audio data without generating any perceptual degradation of audio quality. A binary sequence (the watermark) is derived using energy based features from the audio signal and chirp coding used to embed the watermark in audio data. The chirp coding technique is such that the same watermark can be derived from the ori...

Most ultrasonic guided wave methods require tone burst excitations to achieve some degree of mode purity. In addition, it is often desirable to acquire data using multiple frequencies, particularly during method development when the best frequency for a specific application is not known. However, this process is inconvenient and time-consuming, particularly if extensive signal averaging at each...

A digital modulation method using Chirp-Slope Keying (CSK) is developed for coherent underwater acoustic communications. Effective signal detection is a critical stage in the implementation of any communications system; we will see that CSK solves some significant challenges to reliable detection. This thesis is primarily based on analyzing the effectiveness of CSK through simulations using Mat...

A DSP technique that transforms a digital signal by warping the frequency axis is discussed. The technique corresponds to a mapping of the samples in the z-domain such that they are unevenly spaced around the unit circle. A spectral warping network has the property that a timeshifted impulse function is transformed into a chirp function. This can have useful applications in the analysis of the ...