Doppler measurement using a pair of FM-chirp signals

Coded Excitation in TCD Ultrasound Systems to Improve Axial Resolution

“…This had the disadvantage that it required separate transmit and receive transducers because the periods of transmit and receive overlapped, and also had a range resolution of the same order as conventional systems. Recently, Iwashita et al (2003) and Moriya et al (2005) used a "dual-chirp pulse" or "complementary chirp signal" (i.e., a pulse that contains chirps with increasing frequency modulation and chirps with decreasing frequency modulation) to measure an ultrasound Doppler shift. Their system exploited the range-Doppler coupling effect and used long pulses (100 s or 1000 s, respectively).…”

P1D-2 Fundamental Study for IVUS based on Pulse Compression System

“…We can use the method reported in [3], [4], which detects the Doppler velocity using an FM dual-chirp, i.e., the sum of FM up-and down-chirps, as the transmitted signal. After that, by adding the measured Doppler information to the transmitted signal, we can obtain the ideal kernel function, by which the compressed echo signal has no distortion caused by the motion of the target.…”

“…From this essential interpretation, we propose a new algorithm for efficient measurement of the Doppler velocity based on pattern matching using zero-cross points in the frequency domain. The computational cost of the proposed algorithm can be drastically reduced from that of the method in [3].…”

DOPSCAT: A mission concept for a Doppler wind-scatterometer

“…Radiometric resolution in VV polarization.In order to solve the second problem, we propose to use the Separation-Compression Filter (SCF) by Iwashita et al[4]. The SCF allows filtering the down-chirp interfering signals and the up-chirp interfering signals rising up after up-chirp matched filtering and down-chirp matched filtering respectively.…”