Chirp excitation.

Short-time chirp excitation for wideband identification of dynamic objects

In this paper, some aspects of choosing excitation signals for fast measurement of complex electrical impedance of objects, including impedance of biological tissues, over a wide range of frequencies are discussed. For this purpose, several short-time excitation signals as special cases of chirp signals of near to minimal duration are proposed. The results of analysis and simulation are promisi...

Ultrasound Elasticity Imaging System with Chirp-Coded Excitation for Assessing Biomechanical Properties of Elasticity Phantom

The biomechanical properties of soft tissues vary with pathological phenomenon. Ultrasound elasticity imaging is a noninvasive method used to analyze the local biomechanical properties of soft tissues in clinical diagnosis. However, the echo signal-to-noise ratio (eSNR) is diminished because of the attenuation of ultrasonic energy by soft tissues. Therefore, to improve the quality of elastograp...

Amplitude modulated chirp excitation to reduce grating lobes and maintain ultrasound intensity at the focus of an array.

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...

Aspects of Using Chirp Excitation for Estimation of Bioimpedance Spectrum

Chirp Excitation of Ultrasonic Guided Waves (preprint)

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...