CN113098630A - 1/f noise suppression system and method based on frequency conversion and digital filtering - Google Patents
1/f noise suppression system and method based on frequency conversion and digital filtering Download PDFInfo
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Abstract
The invention provides a 1/f noise suppression system and method based on frequency conversion and digital filtering, the system includes: the optical domain radio frequency shaping module is used for forming an optical signal with information to be detected and radio frequency envelope; the electric domain frequency conversion module is used for converting the optical signal into an electric signal, performing frequency conversion processing on the electric signal and sampling to obtain a sampling signal; the digital filtering module is used for carrying out digital square sum and mean value filtering on the sampling signals to obtain electric intensity information, the electric intensity information is shaped into radio frequency envelope after optical frequency mixing is carried out on original signals, signals of the electric intensity information are amplified, and after electric frequency conversion, optical signals with the radio frequency envelope are converted into intermediate frequency for sampling in an electric frequency mixing mode, so that 1/f noise and interference far away from the 1/f noise are reduced, nano-micro information sensing can be better realized in practical application, and performance and application expansion are improved.
Description
Technical Field
The invention relates to the technical field of signal processing, in particular to a 1/f noise suppression system and a method based on frequency conversion and digital filtering.
Background
The optical micro-nano sensing technology plays a very important role in scientific research, production and life. Detection and extraction of information of interest can be achieved by converting optical signals reflecting, for example, environmental information, properties of objects, etc. into electrical signals. For the detection of nano-micro signals, extremely high sensitivity and extremely low detection limit are required in various application scenes such as homeland security, environmental monitoring, biochemical reaction, physical process, early diagnosis, biological identification and the like. Among many methods for improving the sensitivity and the detection limit, the principle of enhancing the interaction between light and a substance is mostly followed to improve the performance of the whole sensor, for example, a microcavity is introduced on a chip to improve the intensity of local light to increase the interaction between a light field and the substance, nano metal particles are added on the surface of a substrate to produce surface plasma to further improve the interaction between the light and the substance, and a waveguide structure such as a slot waveguide or a slot optical fiber is modified to expose the light field to a substance to be measured or an environment more so as to increase the light response.
However, the prior art has some key problems which prevent the practical application of the prior art: 1. optical microcavities typically require extremely high quality factors (Q values)>106) A better enhancement effect can be achieved, and related tests require a laser with adjustable narrow linewidth; 2. the method for enhancing the interaction between light and substances can increase the local light intensity, can cause irreversible damage to some samples and molecules, and is required to be avoided in the field of actual sensing; 3. based on the slot waveguide, the slot fiber has higher robustness and relatively lower cost, but the solution of directly increasing the interaction area cannot achieve high sensitivity due to the process and the like.
Therefore, how to provide a 1/f noise suppression scheme based on frequency transformation and digital filtering can better realize nano-micro information sensing in practical application, and the technical problems to be solved by technical personnel in the field are needed to be solved.
Disclosure of Invention
The invention provides a 1/f noise suppression system and method based on frequency conversion and digital filtering, which can better realize nano-micro information sensing in practical application, improve performance and expand application.
The invention provides a 1/f noise suppression system based on frequency conversion and digital filtering, comprising:
the optical domain radio frequency shaping module is used for forming an optical signal with information to be detected and radio frequency envelope;
the electrical domain frequency conversion module is used for converting the optical signal into an electrical signal with 1/f noise suppressed, and carrying out frequency conversion processing and sampling on the electrical signal to obtain a sampling signal;
and the digital filtering module is used for carrying out digital square sum and mean value filtering on the sampling signals to obtain electric intensity information and carrying out sensing information extraction and noise analysis on the obtained electric intensity information.
Further, the optical domain radio frequency shaping module comprises: the device comprises a laser beam splitter, a frequency shifter, a light sensing area and a light interference unit;
the laser beam splitter is used for splitting laser into a first beam and a second beam, the first beam enters the parallel frequency shifter, the second beam enters the optical interference unit to serve as reference light, and the second beam is used for performing beat frequency shaping on the first beam output by the frequency shifter;
after the first light beam from the frequency shifter interacts with the substance to be measured in the optical sensing area, the first light beam interferes with the second light beam in the optical interference unit to form an optical signal with information to be measured and a radio frequency envelope.
Further, the frequency shifter is used to subject the input signal to modulation and demodulation, the first beam is maintained at a given frequency, and the output signal is shifted in the frequency domain.
Further, the frequency shifter, the light sensing area and the light interference unit are integrated on a chip.
Further, the optical signal having a radio frequency envelope comprises: optical nonlinear effects, modulators, dark field scattering, michelson interference, mach-zehnder interference, side scattering, back scattering or coupler-wise formed optical signals.
Further, the electric domain frequency conversion module comprises: the device comprises a photoelectric detector, an electric amplifier, an electric filter and a variable frequency sampling unit;
the photoelectric detector is used for converting the optical signal into an electric signal;
the electric amplifier is used for amplifying the electric signal;
the electric filter is used for filtering the amplified electric signal;
and the frequency conversion sampling unit is used for carrying out frequency conversion and orthogonal sampling on the filtered electric signal.
Further, the frequency conversion sampling unit is specifically configured to: searching an optimal electric domain variable frequency point; frequency converting the filtered electric signal to the optimal electric domain frequency conversion point; sampling is carried out by means of orthogonal sampling.
Further, the optimal electrical domain variable frequency point is the frequency of an electrical local oscillator which is larger than the inflection point frequency value of the noise by a preset frequency value.
Further, the digital filtering module includes: the device comprises a signal extraction algorithm unit, a sensing signal unit, a sensing information extraction unit and a noise analysis unit.
On the other hand, an embodiment of the present invention provides a method for suppressing 1/f noise based on frequency transform and digital filtering, which is applied to the above-mentioned 1/f noise suppression system based on frequency transform and digital filtering, and is characterized by including:
forming an optical signal with information to be detected and radio frequency envelope;
converting the optical signal into an electric signal with 1/f noise suppression, and carrying out frequency conversion processing and sampling on the electric signal to obtain a sampling signal;
and carrying out digital sum of squares and mean value filtering on the sampling signals to obtain electric intensity information, and carrying out sensing information extraction and noise analysis on the obtained electric intensity information.
According to the frequency conversion and digital filtering based 1/f noise suppression system and method, original signals are shaped into radio frequency envelopes after optical frequency mixing, the signals per se are amplified, and optical signals with the radio frequency envelopes are converted into intermediate frequency for sampling in an electrical frequency mixing mode after electrical frequency conversion, so that 1/f noise and interference far away from the 1/f noise per se are reduced, nano-micro information sensing can be better realized in practical application, performance is improved, and application is expanded.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the following briefly introduces the drawings needed for the embodiments or the prior art descriptions, and obviously, the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating a prior art direct signal extraction technique;
fig. 3 is a schematic diagram of signal extraction of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 4 is a diagram of an electrical spectrometer signal analysis of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 5 is a second diagram of an electrical spectrometer signal analysis of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 6 shows frequency-converted sampled signal (30kHz) and background electrical noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 7 shows frequency-converted sampling signal (0Hz) and background light noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
FIG. 8 shows the frequency-converted sampling signal (30kHz) and background light noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a signal obtained by frequency conversion sampling based on frequency conversion and digital filtering according to an embodiment of the present invention;
fig. 10 is a variation trend graph based on frequency transformation and digital filtering according to an embodiment of the present invention;
fig. 11 is a second variation trend chart based on frequency transformation and digital filtering according to the embodiment of the present invention;
fig. 12 is a third graph of variation trend based on frequency transformation and digital filtering according to the embodiment of the present invention;
fig. 13 is a fourth variation trend chart based on frequency transformation and digital filtering according to an embodiment of the present invention;
fig. 14 is a fifth variation graph based on frequency transformation and digital filtering according to an embodiment of the present invention;
fig. 15 is a graph of a relationship between a sampling noise amplitude of a frequency-converted sampling signal obtained by analyzing after multiple sampling based on frequency conversion and digital filtering according to an embodiment of the present invention and a frequency;
fig. 16 is a time-domain signal diagram of a finally digitally filtered sensing signal at different sampling frequencies according to the embodiment of the present invention, where the sensing signal is obtained based on frequency conversion and digital filtering;
FIG. 17 is a schematic diagram of an actual detection result of HIV virions based on frequency conversion and digital filtering according to an embodiment of the present invention;
fig. 18 is a schematic structural diagram of a parallel specific sensing based on frequency conversion and digital filtering according to an embodiment of the present invention;
fig. 19 is a flowchart of a 1/f noise suppression method based on frequency transformation and digital filtering according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A frequency transform and digital filtering based 1/f noise suppression system of the present invention is described below in conjunction with fig. 1-18.
As shown in fig. 1, fig. 1 is a schematic structural diagram of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; in one embodiment of the present invention, the present invention provides a 1/f noise suppression system based on frequency conversion and digital filtering, comprising:
an optical domain radio frequency shaping module 110, configured to form an optical signal with information to be detected and having a radio frequency envelope;
an electrical domain frequency conversion module 120, configured to convert the optical signal into an electrical signal with 1/f noise suppressed, perform frequency conversion processing on the electrical signal, and perform sampling to obtain a sampling signal;
and the digital filtering module 130 is configured to perform digital sum-of-squares and mean filtering on the sampling signal to obtain electrical strength information, and perform sensing information extraction and noise analysis on the obtained electrical strength information.
As shown in fig. 2 and 3, fig. 2 is a schematic diagram of signal loading in the prior art sensing technology; fig. 3 is a schematic diagram of signal extraction of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; the principle of 1/f noise suppression based on photoelectric frequency conversion of the present example. Fig. 2 shows that after directly detecting the light sensing signal, the signal to be extracted is buried in low frequency noise due to its very weak. The signal buried in noise is first optically mixed and shaped to the radio frequency envelope and the signal itself will be amplified, this step of the optical frequency conversion being denoted 1 st. After a second (2nd) electrical frequency conversion, the optical signal with the radio frequency envelope is converted to an intermediate frequency for sampling by means of electrical mixing to reduce 1/f noise and interference away from the 1/f noise itself.
As shown in fig. 1, a schematic diagram of a scheme for implementing a sensing function and parallel sensing based on a 1/f noise suppression technology provided by the present invention mainly includes three parts: the device comprises an optical domain radio frequency shaping module, an electric domain frequency conversion module and a digital filtering module. In the optical domain radio frequency shaping, one path of laser light enters a parallel frequency shifter after beam splitting, and the other path of laser light is used as reference light of an interference unit to carry out beat frequency shaping on light output by frequency shifting. The frequency shifter can be acousto-optic frequency shift, single sideband modulation of carrier suppression, optical nonlinear process and the like. After the light with the shifted frequency interacts with the substance to be measured, the light interferes with the previously split laser in the light interference unit to form an optical signal with information to be measured and radio frequency envelope.
That is, the optical domain radio frequency shaping module includes: the device comprises a laser beam splitter, a frequency shifter, a light sensing area and a light interference unit; the laser beam splitter is used for splitting laser into a first beam and a second beam, the first beam enters the parallel frequency shifter, the second beam enters the optical interference unit to serve as reference light, and the second beam is used for performing beat frequency shaping on the first beam output by the frequency shifter; after the first light beam from the frequency device interacts with the substance to be measured in the optical sensing area, the first light beam interferes with the second light beam in the optical interference unit to form an optical signal with information to be measured and a radio frequency envelope.
Wherein for a frequency shifter, an input signal may be subjected to modulation and demodulation, the first beam is shifted in the frequency domain while maintaining a given frequency offset, and an output signal is shifted in the frequency domain. And an optical signal having a radio frequency envelope comprising: optical nonlinear effects, modulators, dark field scattering, michelson interference, mach-zehnder interference, side scattering, back scattering or coupler-wise formed optical signals.
The rf envelope shaped optical signal corresponds to the signal of the first step in fig. 3. After the light is responded on the photoelectric detector, the signal distribution of the light is analyzed by the electric spectrometer as shown in fig. 4 and 5, and fig. 4 is one of the electric spectrometer signal analysis diagrams of the 1/f noise suppression system based on frequency conversion and digital filtering provided by the embodiment of the invention; FIG. 5 is a second diagram of an electrical spectrometer signal analysis of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; . The point of frequency 0 in fig. 4 represents the frequency of the signal in the rf domain (e.g., 100Mhz), and it can be seen that the signal with the information to be measured is mapped on the rf frequency. And the radio frequency signal is affected only by the surrounding flat quantum noise. By changing the light intensity participating in interference, the amplitude of the sampling noise shows a linear variation trend along with the light intensity, which shows that the signal after frequency conversion is not submerged in the 1/f noise of the sampling system at the moment and is not interfered by the 1/f noise, and the direct current component caused by the signal leaving the fundamental frequency is reduced, so that the 1/f noise of the system is reduced. The frequency selection for radio frequency shaping is typically between 10Mhz and 3 Ghz. Meanwhile, for better noise reduction, a band-pass filter and a radio frequency amplifier covering the frequency of the signal can be used, and the frequency shifter, the light sensing area and the light interference unit can be integrated on a chip, so that the use is more convenient.
Further, the electric domain frequency conversion module comprises: the device comprises a photoelectric detector, an electric amplifier, an electric filter and a variable frequency sampling unit; the photoelectric detector is used for converting the optical signal into an electric signal with 1/f noise suppressed; the electric amplifier is used for amplifying the electric signal; the electric filter is used for filtering the amplified electric signal; and the frequency conversion sampling unit is used for carrying out frequency conversion and orthogonal sampling on the filtered electric signal.
As shown in fig. 6, 7 and 8, fig. 6 is a frequency-converted sampling signal (30kHz) and background electrical noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; FIG. 7 shows frequency-converted sampling signal (0Hz) and background light noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; FIG. 8 shows the frequency-converted sampling signal (30kHz) and background light noise spectrum of a 1/f noise suppression system based on frequency conversion and digital filtering according to an embodiment of the present invention; in order to losslessly sample the signal loaded in the rf envelope amplitude, the optical domain rf shaped signal needs to be frequency converted for sampling. Fig. 6 shows a comparison of the signal after frequency conversion in the electrical domain with the electrical noise of the system itself, and it can be seen that in the low frequency region, the signal is affected by 1/f noise. When the radio frequency signal is directly converted to the fundamental frequency by the conventional method, it can be seen that the system is given a higher 1/f noise due to the increase of the direct current (fig. 7), while if shifted to the intermediate frequency (30kHz), it can be seen that the acquisition system is not given much additional low frequency 1/f noise.
Further, the frequency conversion sampling unit is specifically configured to: searching an optimal electric domain variable frequency point (delta f); frequency converting the filtered electric signal to the optimal electric domain frequency conversion point; sampling is carried out by means of orthogonal sampling.
As shown in fig. 9-16, fig. 9 is a schematic diagram of a signal obtained by frequency conversion sampling based on frequency conversion and digital filtering according to an embodiment of the present invention; fig. 10 is one of the trend graphs (Δ f ═ 0Hz) based on frequency transform and digital filtering according to the embodiments of the present invention; fig. 11 is a second variation trend graph (Δ f ═ 3Hz) based on frequency transform and digital filtering according to the embodiment of the present invention; fig. 12 is a third trend graph (Δ f ═ 5Hz) based on frequency transform and digital filtering according to an embodiment of the present invention; fig. 13 is a graph of a variation trend based on frequency transformation and digital filtering according to an embodiment of the present invention (Δ f is 300 Hz); fig. 14 is a graph of a variation trend based on frequency transformation and digital filtering (Δ f 30000 Hz); fig. 15 is a graph of a relationship between a sampling noise amplitude of a frequency-converted sampling signal obtained by analyzing after multiple sampling based on frequency conversion and digital filtering according to an embodiment of the present invention and a frequency; fig. 16 is a time-domain signal diagram of a finally digitally filtered sensing signal at different sampling frequencies according to the embodiment of the present invention, based on frequency conversion and digital filtering.
The embodiment provides a method for searching an optimal electrical domain variable frequency point, which specifically comprises the following steps: 1. the method comprises the steps of defining an electrical local oscillator frequency in frequency conversion sampling to be the same as the frequency of an optical frequency envelope, obtaining a signal 2 with a time length of at least 50s by utilizing orthogonal sampling, repeatedly changing the difference frequency between the electrical local oscillator frequency and the optical frequency envelope to obtain a time domain signal 3 with a second time length of at least 50s, repeating the step 2 for at least 10 times, and approximately linearly increasing and selecting frequency points according to the frequency under a logarithmic coordinate system, wherein the frequency points are (3Hz, 5Hz, 10Hz, 30Hz, 50Hz …). 4. A symbolic function constructed as an illustration in figure 10Counting, defining the total length of the symbol function as a time interval, defining the time interval as a variable, performing cross-correlation with the time domain sampling signals obtained in the first three steps, and calculating the standard deviation, namely
5. And (4) plotting the change of the sampling noise amplitude obtained in the step (4) along with the time interval to obtain the noise condition in a single acquisition under the corresponding frequency. 6. Repeating the steps 1 to 5 at least 5 times to obtain repeated experimental data, wherein data measured for 5 times at different frequencies at a time interval of 1s is plotted, and inverse proportional function 1/f is used in logarithmic coordinateαA fit line is obtained for the low frequency noise amplitude value, and a constant is used for fitting noise points with larger frequency, and the intersection point of the constant and the inverse proportion function can be positioned as the corner frequency (corner frequency) of 1/f noise. 7. In the frequency conversion sampling, the frequency of an electric local oscillator needs to be set slightly larger than the inflection point frequency, so that the requirements of not being interfered by 1/f noise, increasing low-frequency 1/f noise due to a signal and reducing the sampling frequency as much as possible can be met, and the sampling resource is saved. Compared with the noise characteristic of the traditional method, the actual measurement of the sampling noise of the optimized variable frequency sampling optimizes 2 orders of magnitude. The optimal electric domain variable frequency point is the frequency of an electric local oscillator which is larger than the inflection point frequency value of the noise by a preset frequency value.
Further, the digital filtering module includes: the device comprises a signal extraction algorithm unit, a sensing signal unit, a sensing information extraction unit and a noise analysis unit. The frequency-converted sampled signal is recorded, and the electric intensity information related to the light intensity change is recovered by using a digital filtering method. The specific method for digital filtering comprises the following steps: 1. the square sum of the two paths of orthogonal signals is calculated; 2. the squared signal is mean filtered at 50 Hz. When there is no information to be sensed, the resulting intensity signal is shown in fig. 16. It can be seen that the optimized function of frequency-converted sampling plus digital filtering can suppress 1/f noise in the signal.
As shown in fig. 17 and fig. 18, fig. 17 is a schematic diagram of an actual detection result of HIV virions based on frequency conversion and digital filtering according to an embodiment of the present invention; fig. 18 is a schematic structural diagram of parallel specific sensing based on frequency transformation and digital filtering according to an embodiment of the present invention.
FIG. 17 shows the signal obtained by the virus detection with a radius of about 50nm, with a signal-to-noise ratio of up to 20dB, as a result of sensing the scattering signal of the virus particles by the present invention. In the conventional method for directly detecting virus scattering information, it is difficult to detect the signal of the virus. The effectiveness of the method in a sensing system is proved. Fig. 17 b shows a variation signal extracted from the sensing information in the digital filtering module in fig. 1, which is obtained by performing a cross-correlation operation on the sensing signal obtained in the diagram a in fig. 17 by using the sign function constructed in the diagram of fig. 10. The highest snr can be calculated by comparing the signal variation amount of the highest peak value with the noise jitter (standard deviation) in the absence of the peak. If the peak heights in the b-diagram similar to fig. 17 are extracted, the overall distribution of the signal intensity of the test substance can be obtained, and the distribution can be used to obtain the corresponding mean value, so as to estimate the polarizability, scattering intensity or size information of the substance to be tested. By testing standard objects with different sizes, the mean distribution of the signal intensity can be used for estimating the variation trend, and the trend can be used for estimating the related information of other unknown objects.
FIG. 18 shows a scheme for achieving high-sensitivity parallel specific detection based on the framework of FIG. 1. The lines in the figure may represent waveguides or optical fibres, and f represents the frequency. By loading different radio frequency envelopes to the laser and applying different types of biological receptors at different optical interference units, the specificity detection of molecular components, viruses and the like in the same sample can be realized.
The sensing-oriented low-frequency 1/f noise suppression method provided by the invention can break through the detection limit of the original sensing system, greatly improves the signal-to-noise ratio of the signal to be detected, can extract and amplify the weak scattered light signal of a common optical structure from the noise, and realizes the sensing with high signal-to-noise ratio and high sensitivity.
The embodiment of the invention discloses a system for efficiently inhibiting low-frequency 1/f noise (pink noise and flicker noise) in a photoelectric sensing system, which can realize an optical sensing effect with high signal-to-noise ratio and high sensitivity and belongs to the field of optical sensing and noise inhibition. The invention realizes photoelectric response of carrier loading after detection by constructing a beat frequency optical envelope of coherent light source coherent radiation, and realizes critical suppression of low-frequency flicker noise in signal extraction in the sensing process by assisting an optimized variable frequency sampling method. The sensing system processed by the method can achieve the suppression effect of 2 orders of magnitude on the noise of the sampling signal by optimizing the intermediate frequency sampling frequency. The sensing system based on the noise suppression method can realize the detection of single virus particles under a system without optical field enhancement (such as a waveguide and an optical fiber).
The following describes a 1/f noise suppression method based on frequency transformation and digital filtering provided by the present invention, and the following described 1/f noise suppression method based on frequency transformation and digital filtering and the above described 1/f noise suppression system based on frequency transformation and digital filtering can be correspondingly referred to each other.
Referring to fig. 19, fig. 19 is a flowchart of a method for suppressing 1/f noise based on frequency transformation and digital filtering according to an embodiment of the present invention.
In another embodiment of the present invention, a method for suppressing 1/f noise based on frequency transform and digital filtering is provided, which is applied to the above-mentioned system for suppressing 1/f noise based on frequency transform and digital filtering, and includes:
step 110: forming an optical signal with information to be detected and radio frequency envelope;
step 120: converting the optical signal into an electric signal with 1/f noise suppression, and carrying out frequency conversion processing and sampling on the electric signal to obtain a sampling signal;
step 130: and carrying out digital sum of squares and mean value filtering on the sampling signals to obtain electric intensity information, and carrying out sensing information extraction and noise analysis on the obtained electric intensity information.
According to the 1/f noise suppression method based on frequency conversion and digital filtering, original signals are shaped into radio frequency envelopes after optical frequency mixing, the signals of the original signals are amplified, and optical signals with the radio frequency envelopes are converted into intermediate frequency for sampling in an electrical frequency mixing mode after electrical frequency conversion, so that 1/f noise and interference far away from the 1/f noise of the original signals are reduced, nano-micro information sensing can be better realized in practical application, performance is improved, and application is expanded.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A frequency transform and digital filtering based 1/f noise suppression system, comprising:
the optical domain radio frequency shaping module is used for forming an optical signal with information to be detected and radio frequency envelope;
the electrical domain frequency conversion module is used for converting the optical signal into an electrical signal with 1/f noise suppressed, and carrying out frequency conversion processing and sampling on the electrical signal to obtain a sampling signal;
and the digital filtering module is used for carrying out digital square sum and mean value filtering on the sampling signals to obtain electric intensity information and carrying out sensing information extraction and noise analysis on the obtained electric intensity information.
2. The frequency transform and digital filtering based 1/f noise suppression system according to claim 1,
the optical domain radio frequency shaping module comprises: the device comprises a laser beam splitter, a frequency shifter, a light sensing area and a light interference unit;
the laser beam splitter is used for splitting laser into a first beam and a second beam, the first beam enters the parallel frequency shifter, the second beam enters the optical interference unit to serve as reference light, and the second beam is used for performing beat frequency shaping on the first beam output by the frequency shifter;
after the first light beam from the frequency device interacts with the substance to be measured in the optical sensing area, the first light beam interferes with the second light beam in the optical interference unit to form an optical signal with information to be measured and a radio frequency envelope.
3. The frequency transform and digital filtering based 1/f noise suppression system according to claim 2,
the frequency shifter is used for modulating and demodulating an input signal, the first light beam maintains a given frequency offset, and an output signal is offset on a frequency axis.
4. The frequency-translation and digital-filtering based 1/f noise suppression system according to claim 2, wherein the frequency shifter, the light sensing area, and the light interference unit are integrated on a chip.
5. The frequency transform and digital filtering based 1/f noise suppression system according to claim 2,
the optical signal having a radio frequency envelope comprises: dark field scattering, michelson interference, mach-zehnder interference, side scattering, back scattering or coupler-wise formed optical signals.
6. The frequency transform and digital filtering based 1/f noise suppression system according to claim 1,
the electric domain frequency conversion module comprises: the device comprises a photoelectric detector, an electric amplifier, an electric filter and a variable frequency sampling unit;
the photoelectric detector is used for converting the optical signal into an electric signal;
the electric amplifier is used for amplifying the electric signal;
the electric filter is used for filtering the amplified electric signal;
and the frequency conversion sampling unit is used for carrying out frequency conversion and orthogonal sampling on the filtered electric signal.
7. The frequency transform and digital filtering based 1/f noise suppression system according to claim 6,
the frequency conversion sampling unit is specifically used for: searching an optimal electric domain variable frequency point; frequency converting the filtered electric signal to the optimal electric domain frequency conversion point; sampling is carried out by means of orthogonal sampling.
8. The frequency transform and digital filtering based 1/f noise suppression system according to claim 7,
and the optimal electric domain variable frequency point is the frequency of an electric local oscillator which is larger than the inflection point frequency value of the noise by a preset frequency value.
9. The frequency transform and digital filtering based 1/f noise suppression system according to claim 1,
the digital filtering module includes: the device comprises a signal extraction algorithm unit, a sensing signal unit, a sensing information extraction unit and a noise analysis unit.
10. A 1/f noise suppression method based on frequency conversion and digital filtering, which is applied to the 1/f noise suppression system based on frequency conversion and digital filtering according to any one of claims 1 to 9, and is characterized by comprising the following steps:
forming an optical signal with information to be detected and radio frequency envelope;
converting the optical signal into an electric signal with 1/f noise suppressed, and performing frequency conversion processing and sampling on the electric signal to obtain a sampling signal;
and carrying out digital sum of squares and mean value filtering on the sampling signals to obtain electric intensity information, and carrying out sensing information extraction and noise analysis on the obtained electric intensity information.
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| EP1600806A2 (en) * | 1995-08-01 | 2005-11-30 | California Institute Of Technology | Novel opto-electronic oscillators |
| US20180180655A1 (en) * | 2016-09-01 | 2018-06-28 | Imra America, Inc. | Ultra-low noise photonic phase noise measurement system for microwave signals |
| CN108418639A (en) * | 2018-02-11 | 2018-08-17 | 华中科技大学 | A kind of digitlization related detection system and method based on virtual minimum phase signal |
| CN111473857A (en) * | 2020-04-27 | 2020-07-31 | 中国科学院半导体研究所 | Distributed optical fiber sensing system for low frequency detection |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1600806A2 (en) * | 1995-08-01 | 2005-11-30 | California Institute Of Technology | Novel opto-electronic oscillators |
| US20180180655A1 (en) * | 2016-09-01 | 2018-06-28 | Imra America, Inc. | Ultra-low noise photonic phase noise measurement system for microwave signals |
| CN108418639A (en) * | 2018-02-11 | 2018-08-17 | 华中科技大学 | A kind of digitlization related detection system and method based on virtual minimum phase signal |
| CN111473857A (en) * | 2020-04-27 | 2020-07-31 | 中国科学院半导体研究所 | Distributed optical fiber sensing system for low frequency detection |
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