Fast digital phase detection or frequency discrimination using surface acoustic waves

1990 ◽  
Author(s):  
Robert B. Ward
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Frequency Discrimination ◽  
Phase Detection ◽  
Digital Phase ◽  
Digital Phase Detection

Polymer-electrolyte gated graphene transistors for analog and digital phase detection

2011 ◽  
Vol 99 (4) ◽  
pp. 043307 ◽  
Author(s):  
Adarsh Sagar ◽  
Kannan Balasubramanian ◽  
Marko Burghard ◽  
Klaus Kern ◽  
Roman Sordan
Keyword(s):  
Polymer Electrolyte ◽  
Phase Detection ◽  
Digital Phase ◽  
Digital Phase Detection

Digital phase detection approach and its application for AlN dual-mode differential surface acoustic wave sensing

2008 ◽  
Vol 132 (1) ◽  
pp. 272-279 ◽  
Author(s):  
Guopeng Hu ◽  
Jianzeng Xu ◽  
Gregory W. Auner ◽  
Joseph Smolinski ◽  
Hao Ying
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Phase Detection ◽  
Dual Mode ◽  
Digital Phase ◽  
Detection Approach ◽  
Digital Phase Detection

scholarly journals Acousto-Optic Comb Interrogation System for Random Fiber Grating Sensors with Sub-nm Resolution

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3967
Author(s):  
Dragos A. Poiana ◽  
Jose A. Garcia-Souto ◽  
Xiaoyi Bao
Keyword(s):  
Frequency Response ◽  
Acoustic Waves ◽  
Frequency Comb ◽  
Surface Acoustic Waves ◽  
Fiber Grating ◽  
Phase Detection ◽  
Limited Frequency ◽  
Small Cracks ◽  
Non Destructive

The broad-frequency response and nanometer-range displacements of ultrasound detection are essential for the characterization of small cracks, structural health monitoring and non-destructive evaluation. Those perturbations are generated at sub-nano-strain to nano-strain levels. This corresponds to the sub-nm level and, therefore, to about 0.1% of wavelength change at 1550 nm, making it difficult to detect them by conventional interferometric techniques. In this paper, we propose a demodulation system to read the random fiber grating spectrum using a self-heterodyne acousto-optic frequency comb. The system uses a self-heterodyne approach to extract phase and amplitude modulated signals to detect surface acoustic waves with sub-nanometer amplitudes in the frequency domain. The method can detect acoustic frequencies of 1 MHz and the associated displacement. The system is calibrated via phase detection with a heterodyne interferometer, which has a limited frequency response of up to 200 kHz. The goal is to achieve sub-nanometer strain detection at MHz frequency with random fiber gratings.

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