What is ANALOG EAR? What does ANALOG EAR mean? ANALOG EAR meaning, definition & explanation

Experience FAST and SECURE Internet browsing with The Audiopedia owned Android browser. INSTALL NOW - http://bit.ly/2Sm5bi0 What is ANALOG EAR? What does ANALOG EAR mean? ANALOG EAR meaning - ANALOG EAR definition - ANALOG EAR explanation. Source: Wikipedia.org article, adapted under http://bit.ly/yjiNZw license. An analog ear or analog cochlea is a model of the ear or of the cochlea (in the inner ear) based on an electrical, electronic or mechanical analog. An analog ear is commonly described as an interconnection of electrical elements such as resistors, capacitors, and inductors; sometimes transformers and active amplifiers are included. The ear of the typical mammal consists of three parts. The outer ear collects sounds like a horn and guides them to the eardrum. Vibrations of the drum are conveyed to the inner ear via a system of bones called ossicles. These leverage the larger motions of the eardrum to the smaller vibrations of the oval window. This window connects to the cochlea which is a long dual channel arrangement consisting of two channels separated by the basilar membrane. The structure, about 36 mm in length, is coiled to conserve space. The oval window introduces sounds to the upper channel. The lower channel has a round window but this is not driven by the bones of the middle ear. The far end of the structure has a hole between the two channels called the helicotrema that equalizes slowly varying pressures in the two channels. A series of sensory hair cells along the basilar membrane respond to send neural pulses towards the brain. Models for the ear of a direct kind have been created, most notably by Nobel Laureate Georg von Békésy. He used glass slides, razor blades, and an elastic membrane to represent the helicotrema. He could measure vibrations along the basilar membrane in response to different excitations frequencies. He found that the pattern of displacements for given frequency sine wave along the basilar membrane rose somewhat gradually to a peak and thereafter fell. High frequencies favored shorter distances from the oval window than did lower ones. Frequency values approximate a logarithmic distribution with distance. Early mechanical and electrical analog ears were recounted in the 1954 book Analog Methods in Computation and Simulation: ...Barton and Browning also simulated the characteristics of hearing over the range of an octave by making use of 13 pendulum resonators. A modern theory of the dynamics of the cochlea, accounting for the hydrodynamics of the cochlear ducts and the dynamics of the basilar membrane, has been proposed and an electrical analogy developed to check the theory. The "analog ear" is a transmission line made up of 175 section s, each section consisting of 2 inductances (to represent the mass of a slice of fluid and that of the duct) and 4 condensers (to represent duct stiffness). — Walter W. Soroka A direct (mechanical) model uses the variables of air and water pressure, fluid velocity and viscosity, and displacement. An electrical analog model uses a different set of variables, namely, voltage and current. The outer and middle parts of the ear can be represented with a collection of coils, capacitors, and an ideal transformer to represent the leveraging effect of the ossicles. This circuit terminates with a capacitor representing the oval window. From there, the two channels are represented with a sequence of inductors and resistors for fluid flow within each channel with the two channels joined with a sequence of series resonant RLC circuits. Voltages across capacitances represent basilar membrane displacements. Element values along the cochlea are tapered in a logarithmic fashion to represent lowering frequency responses with distance. The pattern of voltages along the basilar membrane can be viewed on an oscilloscope. Average values can be obtained with rectification and shown as patterns using a high speed commutator. The analog ear shows patterns that closely follow those observed by Georg von Békésy on his more direct model. The first relatively complete model was constructed in the early 1960s at the University of Arizona by two graduate students and their faculty mentor with support from the newly established Air Force Bionics program. This work was first summarized in a report: "An Electronic Analog of the Ear", Technical Documentary Report No. AMRL-TDR-1963-60, June 1963, Biophysics Laboratory, 6570-th Aerospace Medical Research Laboratories, Aerospace Medical Division, Air Force Systems Command, by E. Glaesser, W. F. Caldwell, and J. L. Stewart. The report contains an extensive list of references. The work was also reported at Bionics symposia.....