Unidirectional mechanical amplification as a design principle for an active microphone

TL;DR

This paper introduces a novel unidirectional mechanical amplification scheme for active microphones, enhancing weak signal detection and reducing distortion by preventing backward coupling.

Contribution

It proposes a new design principle for unidirectional mechanical amplifiers and demonstrates its application in creating an improved active microphone.

Findings

Amplification lowers the detection threshold for weak signals.

Unidirectionality prevents signal distortion.

The scheme enhances microphone performance.

Abstract

Amplification underlies the operation of many biological and engineering systems. Simple electrical, optical, and mechanical amplifiers are reciprocal: the backward coupling of the output to the input equals the forward coupling of the input to the output. Unidirectional amplifiers that occur often in electrical and optical systems are special non-reciprocal devices in which the output does not couple back to the input even though the forward coupling persists. Here we propose a scheme for unidirectional mechanical amplification that we utilize to construct an active microphone. We show that amplification improves the microphone's threshold for detecting weak signals and that unidirectionality prevents distortion.