Investigation of the Optimal Parameters of the Distributed Fiber Microphone Circuit Based on φ-OTDR for Speech Recognition

A study of the optimal parameters of a distributed fiber microphone circuit based on a laboratory setup of a phase-sensitive optical reflectometer (φ-OTDR), which reproduces the work of φ-OTDR at one point, has been carried out. Various schemes for constructing a microphone based on φ-OTDR and various sampling rates of the analog-to-digital converter are investigated. The optimal configuration of the φ-OTDR circuit is substantiated, which made it possible to ensure high quality of human speech recognition during voice recording by the proposed method with a sampling frequency of 40 kHz. In a standard phrase based on Harvard sentences containing 80 words, 71 words were recognized, i.e., 88.75% of their total number.