Acoustic Channel

Acoustic Channel

 

a combination of equipment and physical media for the transmission of signals by means of audio and ultrasonic phenomena. In an acoustic channel for control or inspection purposes the signals employed are either the passive type—acoustic phenomena produced by the process (usually technological) under inspection—or the active type, which are specially generated. Passive signal acoustic channels are used in industry to check the noise characteristics of manufactured products (for instance, to inspect the quality of assemblies containing gearing); in medicine they are used to study sound from an organism. Active signals in the audio or ultrasonic range are used to transmit information, make remote measurements, determine the parameters of a medium, and detect certain undesirable impurities.

References in periodicals archive ?
The Thorp propagation model [1] is applied to explain the acoustic channel in underwater communications.
Moreover, the major factors influencing in underwater MAC protocol design are man-made noise, Doppler frequency spread, transmission loss, inter-symbol interference (ISI) by multipath propagation, variable propagation delay and all these factors determine the spatial and temporal variability of the acoustic channel. Researchers have developed numerous MAC protocols for underwater [2], [3], and hybrid variants have also been employed [4], [5].
However, underwater acoustic channel (UAC) is one of the most challenging environments for the transmission of information due to the unique characteristics of the UAC such as limited bandwidth, high and variable propagation delays, and significant scattering and multipath.
In UAC, a doubly spread acoustic channel (dispersion in time and frequency) is estimated by orthogonal matching pursuit (OMP) algorithm in [14, 15], which makes use of the sparse structure of channel impulse response.
To decrease the complexity for equalization in large latency underwater acoustic channel, frequency domain channel equalization is presented in [6], but both of these are insufficient to avoid the short range issue owing to the serious attenuation.
The underwater acoustic channel is generally recognized as one of the most challenging channels.
The novice underwater acoustic channel model was illustrated in [8].
We begin by establishing an acoustic channel suitable for confined underwater space.
argue that emotional facial expressions are during the actual production of emotional song, and in the perception, planning, and post-production of emotional song: facial expressions of emotion supplement the acoustic channel of music, and can linger beyond the acoustic dimension of music.
The anti-noise signal y(n) can be modified by the secondary-path function H(z) in the acoustic channel from y(n) to e(n), in this same way as the primary noise signal x(n) is modified by the primary path P(z) from the noise source to the error signal sensor.
Teachers of people who are hearing impaired are trained to use the acoustic channel and view signing as an obstacle to the integration of deaf people into mainstream Hungarian society.