阅读说明：本技术 基于扫频光源的光学传感器数字解调装置及方法 (Optical sensor digital demodulation device and method based on sweep frequency light source ) 是由 冯新焕 陈敬旭 曹元� 王旭东 张杰君 关柏鸥 姚建平 于 2021-08-26 设计创作，主要内容包括：本发明公开了基于扫频光源的光学传感器数字解调装置及方法,装置包括顺序连接的扫频光源、光学传感器、光电探测器、比较器、数字定时器以及数字解调装置；扫频光源输出第一光信号；光学传感器接收第一光信号并输出携带传感信息的第二光信号；光电探测器将第二光信号转为第一电信号并输出；比较器接收第一电信号输出数字电平的第二电信号；数字定时器接收第二电信号输出第一数字信号；数字解调装置接收第一数字信号,通过分析第一数字信号中脉宽序列的特性来实现对传感信息的解调。本发明采用数字解调方式对光学传感器的光谱进行解调,传感信号数据量缩小几个数量级,从根本上解决了时域解调巨量数据的处理问题。(The invention discloses a digital demodulation device and a digital demodulation method for an optical sensor based on a swept-frequency light source, wherein the device comprises the swept-frequency light source, the optical sensor, a photoelectric detector, a comparator, a digital timer and a digital demodulation device which are sequentially connected; the method comprises the steps that a sweep frequency light source outputs a first optical signal; the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information; the photoelectric detector converts the second optical signal into a first electric signal and outputs the first electric signal; the comparator receives the first electric signal and outputs a second electric signal with a digital level; the digital timer receives the second electric signal and outputs a first digital signal; the digital demodulation device receives the first digital signal and demodulates the sensing information by analyzing the characteristics of the pulse width sequence in the first digital signal. The invention adopts a digital demodulation mode to demodulate the spectrum of the optical sensor, reduces the data volume of the sensing signal by several orders of magnitude, and fundamentally solves the problem of processing huge data of time domain demodulation.)

1. The optical sensor digital demodulation device based on the sweep frequency light source is characterized by comprising a frequency-time mapping unit, a comparator, a digital timer and a digital demodulation device which are sequentially connected;

the frequency-time mapping unit is used for mapping the spectral response of the optical fiber sensor to a time domain and comprises a sweep frequency light source, an optical sensor and a photoelectric detector;

the sweep frequency light source, the optical sensor and the photoelectric detector are sequentially connected through optical fibers, and the photoelectric detector, the comparator, the digital timer and the digital demodulation device are sequentially connected through a radio frequency line;

the swept-frequency light source is used for outputting a first optical signal serving as detection light;

the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information;

the photoelectric detector is used for converting the received second optical signal into a first electric signal and outputting the first electric signal;

the comparator receives the first electric signal, processes the first electric signal by setting the reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level;

the digital timer receives the second electric signal, measures the pulse width of the second electric signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal;

the digital demodulation device receives the first digital signal and demodulates the sensing information by analyzing the pulse width sequence in the first digital signal; the demodulation method of the digital demodulation device comprises the following steps:

directly analyzing one or more pulse width information to demodulate the variable quantity of the external parameter;

and calculating partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter.

2. A swept-frequency-source-based optical sensor digital demodulation apparatus as claimed in claim 1, wherein the wavelength of the first optical signal output by the swept-frequency light source is periodically changed with time as probe light to implement frequency-time mapping of the optical sensor spectrum.

3. A swept-frequency-light-source-based optical sensor digital demodulation device as claimed in claim 1, wherein the change of the optical sensor spectral response reflects the change of an external parameter, namely the change of the sensor external parameter causes the change of the optical sensor spectral response, and the change of the external parameter can be demodulated by measuring the change of the spectral response.

4. A swept-frequency-light-source-based optical sensor digital demodulation device as claimed in claim 1, wherein the comparator is specifically configured to compare the reference voltage with the input signal voltage, and if the input signal voltage is greater than the parameter voltage, output a high-level digital signal, otherwise, output a low-level digital signal; the voltage signal output by the photoelectric detector is converted into a second electric signal with only digital high and low levels by reasonably setting a reference voltage, the pulse width in the second electric signal is related to the frequency and the intensity of the first electric signal after frequency-time mapping of the output frequency of the photoelectric detector, namely, the intensity and the frequency change in the spectrum are reflected in the pulse width of the second electric signal.

5. A swept-frequency-source-based optical sensor digital demodulation apparatus as claimed in claim 1, wherein the digital timer is specifically configured to measure pulse widths in the input second electrical signal and output a sequence of pulse width magnitudes within a sweep period as the first digital signal.

6. The optical sensor digital demodulation method based on the sweep frequency light source is characterized in that a frequency-time mapping unit, a comparator, a digital timer and a digital demodulation device which are sequentially connected are arranged, wherein the frequency-time mapping unit comprises the sweep frequency light source, the optical sensor and a photoelectric detector, and the method comprises the following steps:

the method comprises the steps that a sweep frequency light source outputs a first optical signal serving as detection light;

the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information;

the photoelectric detector is used for converting the received second optical signal into a first electric signal and outputting the first electric signal;

the comparator receives the first electric signal, processes the first electric signal by setting the reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level;

the digital timer receives the second electric signal, measures the pulse width of the second electric signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal;

the digital demodulation device receives a first digital signal, and demodulates the sensing information by analyzing a pulse width sequence in the first digital signal, wherein the demodulation method of the digital demodulation device comprises the following steps:

directly analyzing one or more pulse width information to demodulate the variable quantity of the external parameter;

and calculating partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter.

7. A swept-frequency-source-based optical sensor digital demodulation method as claimed in claim 6, wherein the wavelength of the first optical signal output by the swept-frequency light source changes periodically with time as probe light to implement frequency-time mapping of the optical sensor spectrum.

8. A swept-frequency light source-based optical sensor digital demodulation method as claimed in claim 6, wherein the change of the optical sensor spectral response reflects the change of an external parameter, namely the change of the sensor external parameter causes the change of the optical sensor spectral response, and the change of the external parameter is demodulated by measuring the change of the spectral response.

9. A swept-frequency-light-source-based optical sensor digital demodulation method as claimed in claim 6, wherein the comparator is specifically configured to compare the reference voltage with the input signal voltage, and if the input signal voltage is greater than the parameter voltage, output a high-level digital signal, otherwise, output a low-level digital signal; the voltage signal output by the photoelectric detector is converted into a second electric signal only with digital high and low levels by reasonably setting a reference voltage, the pulse width in the second electric signal is related to the frequency and the intensity of the first electric signal after frequency-time mapping of the output frequency of the photoelectric detector, namely, the intensity and the frequency change in the spectrum are reflected in the pulse width of the second electric signal.

10. A swept-frequency-source-based optical sensor digital demodulation method as claimed in claim 6, wherein the digital timer specifically measures pulse widths of the input second electrical signal and outputs a sequence of pulse width magnitudes within a sweep period as the first digital signal.

Technical Field

The invention belongs to the technical field of signal demodulation, and particularly relates to a digital demodulation device and method for an optical sensor based on a swept-frequency light source.

Background

The optical technology can be used for sensing external environment variables with higher sensitivity, and the change of the external parameters can be obtained by demodulating the spectral response variable quantity of the optical sensor. Demodulation of optical sensor spectra can be generally divided into spectral domain demodulation and time domain demodulation. The spectrum domain demodulation generally uses a spectrometer to directly measure the spectrum variation of the sensing device, but the spectrum domain demodulation has the defects of high cost, low demodulation speed, low resolution (the resolution of a common spectrometer is 0.02nm, namely 2.5 GHz), and the like, so that the spectrum domain demodulation is limited in practical application (such as wearable health monitoring, portable safety engineering monitoring, and the like). The other time domain demodulation is based on a frequency-time mapping technology, a spectrum is mapped to a time domain, and then sensing information is acquired through an analog-digital converter. The reason that the computational cost is high is that the high-speed acquisition of the time domain can generate huge data volume in a short time, a common low-power consumption chip cannot meet the computational requirement at all, even a personal computer is used, the computational requirement is not sufficient, the problem of high power consumption is directly brought due to the high computational requirement, and the implementation in wearable application is difficult.

Disclosure of Invention

The invention mainly aims to overcome the defects and shortcomings of the existing sensing demodulation technology, and provides a digital demodulation device and a digital demodulation method for an optical sensor based on a sweep frequency light source, which directly perform digital demodulation on a time domain signal after frequency-time mapping of the optical sensor, so that the data volume of a sensing signal is directly reduced by several orders of magnitude.

In order to achieve the purpose, the invention adopts the following technical scheme:

the optical sensor digital demodulation device based on the sweep frequency light source comprises a frequency-time mapping unit, a comparator, a digital timer and a digital demodulation device which are sequentially connected;

the frequency-time mapping unit is used for mapping the spectral response of the optical fiber sensor to a time domain and comprises a sweep frequency light source, an optical sensor and a photoelectric detector;

the sweep frequency light source, the optical sensor and the photoelectric detector are sequentially connected through optical fibers, and the photoelectric detector, the comparator, the digital timer and the digital demodulation device are sequentially connected through a radio frequency line;

the swept-frequency light source is used for outputting a first optical signal serving as detection light;

the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information;

the photoelectric detector is used for converting the received second optical signal into a first electric signal and outputting the first electric signal;

the comparator receives the first electric signal, processes the first electric signal by setting the reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level;

the digital timer receives the second electric signal, measures the pulse width of the second electric signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal;

the digital demodulation device receives the first digital signal and demodulates the sensing information by analyzing the pulse width sequence in the first digital signal; the demodulation method of the digital demodulation device comprises the following steps:

directly analyzing one or more pulse width information to demodulate the variable quantity of the external parameter;

and calculating partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter.

Furthermore, the wavelength of the first optical signal output by the sweep frequency light source changes along with the time period, and the first optical signal is used as detection light to realize frequency-time mapping of the optical sensor spectrum.

Furthermore, the change of the spectral response of the optical sensor reflects the change of the external parameter, namely the change of the external parameter of the sensor leads to the change of the spectral response of the optical sensor, and the change of the external parameter can be demodulated by measuring the change of the spectral response.

Further, the comparator is specifically configured to compare the reference voltage with the input signal voltage, and if the input signal voltage is greater than the parameter voltage, output a high-level digital signal, otherwise, output a low-level digital signal; the voltage signal output by the photoelectric detector is converted into a second electric signal with only digital high and low levels by reasonably setting a reference voltage, the pulse width in the second electric signal is related to the frequency and the intensity of the first electric signal after frequency-time mapping of the output frequency of the photoelectric detector, namely, the intensity and the frequency change in the spectrum are reflected in the pulse width of the second electric signal.

Further, the digital timer is specifically configured to measure a pulse width in the input second electrical signal, and output a sequence of pulse width magnitudes in a frequency sweep period, which is the first digital signal.

The invention also provides a digital demodulation method of the optical sensor based on the swept-frequency light source, which is characterized in that a frequency-time mapping unit, a comparator, a digital timer and a digital demodulation device which are sequentially connected are arranged, wherein the frequency-time mapping unit comprises the swept-frequency light source, the optical sensor and a photoelectric detector, and the method comprises the following steps:

the method comprises the steps that a sweep frequency light source outputs a first optical signal serving as detection light;

the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information;

the photoelectric detector is used for converting the received second optical signal into a first electric signal and outputting the first electric signal;

the comparator receives the first electric signal, processes the first electric signal by setting the reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level;

the digital timer receives the second electric signal, measures the pulse width of the second electric signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal;

the digital demodulation device receives a first digital signal, and demodulates the sensing information by analyzing a pulse width sequence in the first digital signal, wherein the demodulation method of the digital demodulation device comprises the following steps:

directly analyzing one or more pulse width information to demodulate the variable quantity of the external parameter;

and calculating partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter.

Furthermore, the wavelength of the first optical signal output by the sweep frequency light source changes along with the time period to be used as detection light, and frequency-time mapping of the optical sensor spectrum is achieved.

Furthermore, the change of the optical sensor spectral response reflects the change of the external parameter, namely the change of the external parameter of the sensor leads to the change of the optical sensor spectral response, and the change of the external parameter is demodulated by measuring the change of the spectral response.

Further, the comparator is specifically configured to compare the reference voltage with the input signal voltage, and if the input signal voltage is greater than the parameter voltage, output a high-level digital signal, otherwise, output a low-level digital signal; the voltage signal output by the photoelectric detector is converted into a second electric signal only with digital high and low levels by reasonably setting a reference voltage, the pulse width in the second electric signal is related to the frequency and the intensity of the first electric signal after frequency-time mapping of the output frequency of the photoelectric detector, namely, the intensity and the frequency change in the spectrum are reflected in the pulse width of the second electric signal.

Further, the digital timer measures the pulse width of the input second electrical signal, and outputs a sequence of pulse widths in a sweep frequency period, which is the first digital signal.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the invention demodulates the sensing information of the optical sensor by adopting a digital demodulation mode, the data volume of the sensing signal is directly reduced by several orders of magnitude, the processing problem of demodulating huge data of the optical sensor time domain is fundamentally solved, and the invention has the advantages of low computational cost, high demodulation speed and the like, so that more optical sensors can be applied to low-power-consumption wearable scenes.

2. The price of the comparator and the digital timer used in the invention is far lower than that of the analog-to-digital converter, so the invention has the advantages of low hardware cost, small volume and the like.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus of the present invention;

FIG. 2 is a flow chart of the method of the present invention;

the reference numbers illustrate: 1-a frequency-time mapping unit; 11-swept source; 12-an optical sensor; 13-a photodetector; 2-a comparator; 3-a digital timer; 4-digital demodulating equipment.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Examples

As shown in fig. 1, the digital demodulation apparatus of an optical sensor based on a swept-frequency light source of the present invention includes a frequency-time mapping unit 1 (including a swept-frequency light source 11, an optical sensor 12, and a photodetector 13), a comparator 2, a digital timer 3, and a digital demodulation apparatus 4, which are connected in sequence;

the sweep frequency light source, the optical sensor and the photoelectric detector are sequentially connected through optical fibers, and the photoelectric detector, the comparator, the digital timer and the digital demodulation device are sequentially connected through a radio frequency line;

the frequency-time mapping unit 1 comprises a sweep frequency light source 11, an optical fiber sensor 12 and a photoelectric detector 13, and is used for mapping the spectral response of the optical fiber sensor to a time domain and outputting a first electric signal;

the swept-frequency light source 11 is configured to output a first optical signal, where a wavelength of the first optical signal changes periodically with time, and the first optical signal is used as probe light to implement frequency-time mapping of an optical sensor spectrum. In the embodiment, the swept-frequency light source adopts a Fourier domain mode-locked laser.

The optical sensor 12 receives the first optical signal and outputs a second optical signal carrying sensing information; the change of the spectral response of the optical sensor reflects the change of the external parameter, namely the change of the external parameter of the sensor leads to the change of the spectral response of the optical sensor, and the change of the external parameter can be demodulated by measuring the change of the spectral response. In this embodiment, the optical sensor is an inclined fiber grating with a gold-plated surface.

The photodetector 13 is configured to convert the received second optical signal into a first electrical signal and output the first electrical signal;

the comparator 2 receives the first electric signal, processes the first electric signal by setting a reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level; the function of the comparator is: comparing the reference voltage with the input first electric signal, if the input voltage is larger than the parameter voltage, outputting a high-level digital signal, otherwise, outputting a low-level digital signal.

The comparator is a core device of the device, and can convert the voltage signal output by the photoelectric detector into a second electric signal with only digital high and low levels by reasonably setting a reference voltage, wherein the pulse width in the second electric signal is related to the frequency and the intensity of the first electric signal after the photoelectric detector 13 outputs frequency-time mapping, namely the change of the intensity and the frequency in the spectrum can be reflected in the pulse width of the second electric signal.

The digital timer 3 receives the second electrical signal, measures the pulse width of the second electrical signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal; the digital timer is used for measuring the pulse width of the second electrical signal, and is not limited to be a digital timer, but may be a timer inside a microcontroller or in other forms as long as the pulse width can be measured, and in this embodiment, a timer inside an STM32H750 microcontroller is used.

The digital demodulating apparatus 4 receives the first digital signal, and demodulates the sensing information by analyzing the pulse width sequence in the first digital signal, and the demodulating method of the digital demodulating apparatus includes but is not limited to:

(1) directly analyzing one or more pulse width information to demodulate the variable quantity of the external parameter;

(2) calculating partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter;

in this embodiment, a neural network algorithm is used to directly calculate the first digital signal to obtain the variation of the external parameter.

Based on the device in the foregoing embodiment, the present invention further provides a digital demodulation method for an optical sensor based on a swept-frequency light source, as shown in fig. 2, including the following steps:

the method comprises the steps that a sweep frequency light source outputs a first optical signal serving as detection light;

the optical sensor receives the first optical signal and outputs a second optical signal carrying sensing information;

the photoelectric detector converts the received second optical signal into a first electric signal and outputs the first electric signal;

the comparator receives the first electric signal, processes the first electric signal by setting the reference voltage of the comparator and outputs the first electric signal as a second electric signal of a digital level;

the digital timer receives the second electric signal, measures the pulse width of the second electric signal, and outputs a sequence of the pulse width in a sweep frequency period as a first digital signal;

the digital demodulation device receives the first digital signal, and demodulates the sensing information by analyzing the pulse width sequence in the first digital signal, wherein in this embodiment, the demodulation method of the digital demodulation device is to calculate partial or whole data of the first digital signal by using a neural network algorithm to obtain the variation of the external parameter.

It should also be noted that in this specification, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.