Especially in applications like teleconferencing and hands-free communication systems, it is of vital importance to compensate acoustic echos and thus prevent the users from listening to delayed version of their own speech [3].
To avoid bias introduced by different echo clarity on different substrates, we measured shadow size cast by each specimen from slate, because this substrate gave the most homogeneous substrate echoes and thus the most clearly defined shadows.
In addition, measurements from three different look angles have made it possible to study the aspect angle dependence of the echo strength and thus indirectly the plasma dynamics around the meteor head and fragmentation of individual meteors in the atmosphere (Kero et al. 2008a, b).
An object, subject to stress, distorts proportionally to the intensity of the applied stress and depending on the material it is made of; it is possible to evaluate the modification of the echo signal and thus to compute how the different tissues distort (if they are soft) or move (if they are hard) compared to the probe position.
MRI has been shown previously to correlate with cartilage histology [ 55]. 3D requires a gradient echo sequence and thus there is an increase in the potential for susceptibility artefacts in the follow-up studies; consequently, there is a compromise between the greater degree of resolution obtained in such 3D sequences and the increase in obvious postoperative artefacts.
Sound has to travel through the air to the object, in this case the insect, and back to the sender to be perceptible as an echo, and is thus strongly subjected to attenuation.
The single-shot fast spin echo sequence (SSFSE) or RARE sequence [15] uses spin echoes (compared with FLASH and bSSFP, which utilise gradient echoes) and is thus conceptually different from the previous imaging sequences.
Given the high call frequencies of the bats (80 115 kHz, see Fig. 1) the resulting strong attenuation of calls and echoes with distance and thus the restricted perceptual space of horseshoe bats, 8 m clutter-free space ahead was certainly a very open situation for the bats.
Once this noise-corrupted speech is transmitted through loudspeaker, echo signal is generated and thus the microphone after some initial time delay will receive noise-corrupted speech and echo of previously uttered speech.
Modulated gradient spin echo (MGSE) sequences are designed to measure diffusion spectrum by applying gradients that cause oscillation of the spin dephasing function and thus echo attenuation from which the diffusion spectrum at the frequency of the dephasing oscillation is calculated.
