In previous experiments, the researchers used a three-crystal system, but they now have a way to communicate with just two crystals. The first one, located outside the vessel, vibrates at 1 MHz, causing an ultrasonic wave to travel through the wall. On the other side, the second crystal vibrates in a way that modulates how much of the initial wave reflects back to the first crystal. It is through these modulations that the second crystal encodes whatever measurements an internal sensor has recorded, and the first crystal is able to retrieve this data by detecting the modulations. The researchers have shown that this setup can send 50,000 bits per second across the wall. Moreover, all of the internal electronics, including crystal and sensor, can be powered by skimming off a portion of the energy in the ultrasonic waves coming from the first crystal outside the vessel.
The talk, "Two ultrasonic transducer through-wall communication system analysis" (2pEA5) by Henry A. Scarton is at 2:30 p.m. on Tuesday, November 11.
14) UNDERSTANDING PITCH PERCEPTION MAY ENHANCE LEARNING
A team of researchers from Northwestern University has investigated how native speakers of tone and non-tone languages perceive musical pitch. Tone languages like Mandarin Chinese use pitch to differentiate words. This study and its results may provide further insight into how humans process auditory input, and the possible impact of experience on auditory processing, insight that could be used in the classroom to enhance auditory-based learning.
In Mandarin Chinese, as in other so-called "tone languages", the pitch of a word (its "tone") basically determines its meaning, while non-tonal language
|Contact: Jason Bardi|
American Institute of Physics