Estimation of Parameter Variation of Wideband Signals and their Fields in Media with Attenuation

摘要

Wideband signals and their fields in media with frequency-dependent attenuation have been considered using an example of the analysis of propagation of ultrasonic signals in biological media. An analytical expression for the spatial frequency response of the layer of biological tissue with frequency-dependent attenuation for diagnostically meaningful frequency range was obtained by using a linear approximation of the problem under consideration. Quantitative estimates of the impact of a layer of biological tissue with attenuation on a radio pulse with Gaussian envelope were obtained. The presence of frequency-dependent attenuation in medium was shown to result in variation of spatial selectivity of antenna during its operation with wideband signals. The estimates of variation of spatial selectivity parameters are presented in case of using the radio pulses with Gaussian envelope.