The measurement of acoustic impedance with the aid of the telephone receiver

Kennelly, A. E.

doi:10.1016/s0016-0032(25)90149-4

Cited by 7 publications

(1 citation statement)

References 11 publications

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“…Historically, this work can be viewed as the first mechanical/acoustic impedance calibration purely from the electrical measurements. This idea was extended to compute acoustic impedance based on purely electrical data [10]. Given the practical importance of this technique, it needed to be fully characterized.…”

Section: Introductionmentioning

confidence: 99%

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2019

Int J Magnetics Electromagnetism

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We investigate a classical notion denoted as 'Motional impedance (Z mot )' first developed by Kennelly in 1912, then explored by many other researchers early in the 20 th century. Due to long history to establish impedance properties, Z mot has not been clearly understood with respect to classical impedance properties which makes retroactive study of the Z mot worthy. In this study, we project Z mot 's unique characteristics onto anti-reciprocity where every electro-mechanical system as modeled by a gyrator. This work also clarifies that Z mot is a type of transfer impedance, thus is not necessarily to be a minimum-phase nor a Positive-Real function. Based on simulation, this study shows a shunt eddy current loss on the electrical side of the system is one possible source of the negative real part of Z mot which leads negative real part in Z mot plots. By taking a Balance Armature Receiver (BAR) as a specific example of the electro-mechanical systems, we also explore the (non)linear approximation principal of the BAR based on the magnetic force and hysteresis characteristics. We believe that this study puts anti-reciprocal physics on both the empirical and theoretical basis.

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Section: Introductionmentioning

confidence: 99%