Talk story about ultrasonic & supersonic sound.
According to the oscillation frequency, acoustic waves have been classified to different fields that cover the audio, ultrasonic and infrasonic frequency range, or seismic waves at much larger scale which are waves of energy travelling through the Earth's layer.
This system is specially dedicated to piezo sensors and piezo transducers (audio and ultrasonic bands up to 10 MHz).
Birds chirp, cats meow, a mouse form darts across the screen and a mobile of metal fish reflects light The audio includes ultrasonic squeaks an octave lower and higher than what a human ear can detect.
The Android and search giant has launched Tez, a free mobile wallet in India that will let users link up their phones to their bank accounts to pay for goods securely in physical stores and online, and for person-to-person money transfers with a new twist: Audio QR, which uses ultrasonic sounds to let you exchange money, bypassing any need for NFC.
They then used audio equipment to record the ultrasonic calls.
A directional audible sound can be generated in air by means of the nonlinear interaction between intense amplitude modulated (AM) ultrasonic waves, which attracts much attention in the audio industry.
Acoustic stimuli were presented through an ultrasonic speaker (ScanSpeak, Avisoft Bioacoustics, Berlin, Germany) using an external sound card with a sampling rate of 192 kHz (Fire Wire Audio Capture FA-101, Edirol, London, UK) and a portable ultrasonic power amplifier with a frequency range of 1 125 kHz (Avisoft Bioacoustics).
Specifically, plants emit sound waves at the lower end of the audio range within 10 240 Hz (audio acoustic emissions) as well as ultrasonic acoustic emissions (UAE) ranging from 20 to 300kHz.
