Optical Fiber Michelson Speech Monitoring System and Its Noise-Smooth Sound Extraction Method
A monitoring system and extraction method technology, applied in speech analysis, measurement of ultrasonic/sonic/infrasonic waves, instruments, etc., can solve the problems of unstable noise, increased cost, unstable voice monitoring, etc., to suppress unstable noise and solve noise. The effect of changing and stabilizing the sound monitoring effect
Active Publication Date: 2022-03-18
FUDAN UNIV
View PDF0 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Due to the influence of the shot noise of the photodetector, when the speech signal is demodulated using the traditional phase demodulation algorithm based on the 3×3 coupler, the intensity of the noise will change with the drift of the working point of the interferometer, that is, the noise will appear unstable situation
This unstable noise will have a certain impact on voice monitoring
In the existing technology, when controlling the working point of the interferometer, it is necessary to add active devices such as piezoelectric ceramics or use variable wavelength light sources in the sensing fiber part, which will increase the cost and reduce the ability to resist electromagnetic interference.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0040] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.
[0041] The present invention is based on the speech sensing system of Michelson fiber optic interferometer, as figure 1As shown, the narrowband laser used in this system is a distributed feedback laser (DFB) with a center wavelength of 1550.12nm. Light is coupled out of the core as it passes through the knotted fiber. Three photodetectors PD1, PD2 and PD3 are used for photoelectric conversion. The sensing fiber is exposed to the environment and is used to detect the sound or vibration in the environment, and the reference fiber is encapsulated in a sound-proof material to enhance the detection sensitivity. The system requires no phase or frequency modulation in the reference arm or laser, so there are no active components in the optical domain. In the fiber loop, the laser light emitted by the DFB will be reflected by the first Faraday ro...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention belongs to the technical field of optical fiber sensing, in particular to an optical fiber Michelson voice monitoring system and a sound extraction method with stable noise. The voice monitoring system of the present invention is based on the existing voice monitoring system, adding an optical circulator, leading the return light in the arm connected to the light source of the 3×3 optical fiber coupler to the photoelectric detector, and realizing three-way photoelectric detection , and prevent the reflected signal light from entering the laser; the invention uses the proportional relationship between the shot noise and the detection light intensity to establish a sound extraction method with stable noise. The method of the invention can ensure that the monitored sound has a stable background noise without implementing the operating point control technology of the interferometer, so that the system has a stable voice monitoring effect, and ensures the anti-electromagnetic interference ability of the optical fiber voice sensor and the system performance. simplicity.
Description
technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a voice monitoring system based on a Michelson interferometer and a sound extraction method with stable noise. Background technique [0002] Optical fiber sensing has the advantages of high sensitivity, anti-electromagnetic interference, corrosion resistance, simple structure and low power consumption, and can replace existing electrical sensors in many occasions. The fiber optic sensing voice monitoring system based on Michelson interferometer has the advantages of small size, anti-interference, and good concealment, and can be widely used in special application scenarios such as prisons and underground corridors. Due to the influence of the shot noise of the photodetector, when the speech signal is demodulated using the traditional phase demodulation algorithm based on the 3×3 coupler, the intensity of the noise will change with the drift of the workin...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): G01H9/00G10L21/02G10L25/48
CPCG01H9/004G10L25/48
Inventor 胡雨晗宋秋衡彭和阔吴红艳贾波
Owner FUDAN UNIV