Microwave photon broadband weak signal receiving device

Abstract

A microwave photon broadband weak signal receiving device comprises a direct modulation laser, a light adjustable attenuator, a photoelectric detector, a first amplifier, a first power divider, a spectrum analyzer, a second amplifier, a filter and a second power divider. The direct modulation laser, the light adjustable attenuator, the photoelectric detector, the first amplifier, the first power divider, the second amplifier, the tunable filter and the second power divider are sequentially connected end to end to form a photoelectric oscillation loop. Compared with the prior art, the input signal is coupled into the photoelectric oscillation loop, the photoelectric oscillation loop is in a critical oscillation starting state by controlling the gain of the photoelectric oscillation loop, the oscillation signal is generated by utilizing the interaction between light and an electric signal, and the signal is amplified, filtered and the like. High-efficiency identification and receiving processing of weak signals are realized, and stability and reliability of signal receiving are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of signal processing, in particular to a microwave photon broadband weak signal receiving device. Background Art

[0002] As the demand for greater bandwidth increases, more and more attention is being paid to microwave radar signals that use higher frequency bands. However, high-frequency microwave signals are susceptible to loss during atmospheric transmission, especially in humid environments, which can cause the echo signals received during radar detection to be very weak and the signal-to-noise ratio to be very low. Therefore, it is urgent to develop a microwave photon broadband weak signal receiving device to achieve broadband weak signal reception. Summary of the invention

[0003] The present application provides a microwave photon broadband weak signal receiving device to solve the problem of weak high-frequency microwave signals and low signal-to-noise ratio during existing radar detection.

[0004] In order to achieve the above-mentioned purpose, this application adopts the following technical solution.

[0005] Provided is a microwave photon broadband weak signal receiving device, comprising a directly modulated laser, an optically adjustable attenuator, a photodetector, a first amplifier, a first power divider, a spectrum analyzer, a second amplifier, a filter, and a second power divider;

[0006] The directly modulated laser, the optically adjustable attenuator, the photodetector, the first amplifier, the first power divider, the second amplifier, the tunable filter and the second power divider are sequentially connected end to end to form a photoelectric oscillation loop; the two output ends of the first power divider are respectively connected to the second amplifier and the spectrum analyzer; the second power divider has an input end for receiving weak signals.

[0007] The optoelectronic oscillator is an existing technology. Its core principle is to use the photoelectric reversal phenomenon to convert and feedback the optical signal and the electrical signal so that the system can continuously generate a stable oscillation output. Specifically, the existing optoelectronic oscillator consists of a photomultiplier tube, a feedback circuit and an output circuit. First, the photomultiplier tube converts the optical signal into an electrical signal and inputs it into the feedback circuit. The feedback circuit forms an oscillation loop through components such as capacitors and inductors, and adds the feedback signal to the input signal to generate self-excited oscillation. The output circuit amplifies the oscillation signal and outputs it to form a stable electromagnetic field wave. The starting principle of the optoelectronic oscillator is to use the feedback loop to maintain the oscillation, and usually uses the condition that the positive feedback gain is greater than 1 to generate oscillation. The signal generated by the oscillator is fed back to the oscillator through optical devices such as optical fiber rings, FBG (Fiber Bragg Grating) and optical polarizers, and is coherently superimposed with the generated signal. After amplification, it is fed back to the oscillator through optical devices again, and the cycle continues to expand until a steady-state oscillation is generated. Its frequency is determined by the internal components of the oscillator. For example, for a simple LC circuit, the oscillation frequency is It is related to the parameters of the components. Generally speaking, the use of optical devices such as FBG can achieve precise frequency control and ensure the frequency stability of the oscillator.

[0008] The above scheme couples the input signal into the photoelectric oscillation loop, controls the gain of the photoelectric oscillation loop to put the photoelectric oscillation loop in a critical oscillation state, utilizes the interaction between light and electrical signals to generate an oscillation signal, and achieves efficient recognition and reception of weak signals through amplification and filtering, thereby improving the stability and reliability of signal reception.

[0009] In some embodiments, the first amplifier and the second amplifier are both narrowband microwave amplifiers.

[0010] In some embodiments, the directly modulated laser is connected to the optical variable attenuator via a single-mode optical fiber.

[0011] In some embodiments, a processor is further included; the filter is an electrically controllable tunable filter, and the processor is communicatively connected to the electrically controllable tunable filter.

[0012] The present application has at least the following technical effects or advantages: by coupling the input signal into the photoelectric oscillation loop, by controlling the gain of the photoelectric oscillation loop to put the photoelectric oscillation loop in a critical oscillation state, by utilizing the interaction between light and electrical signals to generate an oscillation signal, and through amplification and filtering and other processing, efficient recognition and reception processing of weak signals can be achieved, thereby improving the stability and reliability of signal reception. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a microwave photon broadband weak signal receiving device in one embodiment of the present application. DETAILED DESCRIPTION

[0014] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0015] See also Figure 1 A microwave photon broadband weak signal receiving device includes a directly modulated laser 1, an optically adjustable attenuator 3, a photodetector 4, a first amplifier 5, a first power divider 6, a spectrum analyzer ESA, a second amplifier 7, an electrically controlled tunable filter 8, a second power divider 9 and a processor 10.

[0016] Among them, the directly modulated laser 1, the optical adjustable attenuator 3, the photodetector 4, the first amplifier 5, the first power divider 6, the second amplifier 7, the electrically controlled tunable filter 8 and the second power divider 9 are connected end to end in sequence to form an optoelectronic oscillation loop. In the optoelectronic oscillation loop, the directly modulated laser 1 is connected to the optical adjustable attenuator 3 through a single-mode optical fiber 2, and the optical adjustable attenuator 3 is connected to the photodetector 4 through an optical fiber to form an optical link. The first amplifier 5, the first power divider 6, the second amplifier 7, the electrically controlled tunable filter 8 and the second power divider 9 are connected through a cable to form a radio frequency link. One of the output ends of the first power divider 6 is connected to the second amplifier 7, and the other output end is connected to the spectrum analyzer ESA. The second power divider 9 has an input end 11 for receiving weak signals. The electrically controlled tunable filter 8 is controlled by a processor 10 to perform frequency selection.

[0017] Specifically, the directly modulated laser can adopt an 18GHz bandwidth directly modulated laser, the optically adjustable attenuator can adopt an optically variable attenuator with a wavelength of 155nm, the photodetector can adopt a U2TBPRV2125AM double-balanced detector, the first amplifier and the second amplifier can both adopt narrowband microwave amplifiers, the first power divider and the second power divider can both adopt a 50:50 electric power splitter, and the electrically controlled tunable filter can adopt a Varian 312M439 filter.

[0018] Working principle: A weak signal is input into the input end 11, and the RF signal is modulated onto the optical signal through the direct modulation laser 1. The direct modulation laser 1 is used to realize the functions of the light source and the modulator at the same time, reducing the frequency selection characteristics brought by the electro-optical modulator. Single-mode optical fiber 2 is used as an energy storage element. When the optical signal passes through the optical fiber, the power attenuation phase changes. The optical adjustable attenuator 3 changes the output optical power by controlling the attenuation of the optical fiber link, thereby reducing the input loss of the photoelectric conversion process. The optical signal passes through the photodetector 4 and becomes a RF signal. The photodetector 4 ensures the connection between the optical link and the RF link. The RF signal passes through the first amplifier 5, and the power becomes larger, which offsets the insertion loss brought about by the photoelectric / electro-optical conversion process. The first power divider 6 inputs a part of the signal into the spectrum analyzer ESA. The spectrum analyzer ESA (built-in processor) converts the electrical signal into a digital signal, and performs power amplification processing on the digital signal, and finally obtains the amplified weak signal. Another part of the signal is input to the electrically controlled tunable filter 8 through the second amplifier 7, and the electrically controlled tunable filter 8 is controlled by the processor 10 to select the frequency. Finally, the weak broadband signal input by the second power divider 9 is combined with the input end 11 to input the optical link to form an optoelectronic oscillation loop.

[0019] When working, a weak signal is modulated onto the laser using a direct modulation laser to obtain an optical signal;

[0020] Photodetectors convert light signals into electrical signals;

[0021] The first amplifier is used to amplify the electrical signal;

[0022] The first power divider divides the electrical signal into a first electrical signal and a second electrical signal;

[0023] The spectrum analyzer converts the first electrical signal into a digital signal, and performs power amplification on the digital signal to obtain an amplified weak signal; the second amplifier amplifies the second electrical signal;

[0024] The filter filters the second electrical signal;

[0025] The second power divider combines the filtered second electrical signal with the weak signal and inputs the combined signal into the directly modulated laser to form a photoelectric oscillation loop.

[0026] Detection method: obtain the center frequency of the weak signal, take the absolute value of the difference between the frequency of the weak signal and the output frequency of the optoelectronic oscillation loop as the output frequency of the first power divider; use the attenuator to adjust the power of the output signal, and use the spectrum analyzer to measure the receiving sensitivity and test range of the microwave photon broadband weak signal receiving device. By adopting the above method, the receiving sensitivity of the above microwave photon broadband weak signal receiving device can reach -70dBm.

[0027] In the past, signal receiving systems would have noise interference, and weak signals were often masked by various noises in the environment. These noises would reduce the signal-to-noise ratio of the signal, making it difficult for weak signals to be accurately received and analyzed. At the same time, weak signals may be affected by factors such as propagation loss and path attenuation during transmission, resulting in a decrease in signal strength. At the receiving end, due to signal attenuation, the received weak signal may be very weak and even difficult to distinguish from noise. The microwave photon broadband weak signal receiving device proposed in this application converts the photoelectric oscillation loop into a signal, and the function of the electrically controlled tunable filter is a narrowband filter, which processes weak signals to achieve the effect of receiving weak signals and improve the stability and reliability of signal reception.

[0028] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0029] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various utility model aspects, in the above description of exemplary embodiments of the utility model, the various features of the utility model are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: the claimed utility model requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims, the utility model aspects are less than all the features of the previously disclosed single embodiment. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the utility model.

[0030] Those skilled in the art will appreciate that the modules or units or groups of the devices in the examples disclosed herein may be arranged in the device as described in the embodiment, or alternatively may be located in one or more devices different from the devices in the example. The modules in the foregoing examples may be combined into one module or may be divided into multiple submodules.

[0031] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or groups in the embodiments may be combined into one module or unit or group, and in addition they may be divided into a plurality of submodules or subunits or subgroups. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0032] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the following claims, any one of the claimed embodiments may be used in any combination.

[0033] In addition, some of the embodiments are described herein as a combination of methods or method elements that can be implemented by a processor of a computer system or by other devices that perform the functions. Therefore, a processor with necessary instructions for implementing the method or method elements forms a device for implementing the method or method elements. In addition, the elements described herein of the device embodiments are examples of devices that are used to implement the functions performed by the elements for the purpose of implementing the utility model.

[0034] The various techniques described herein can be implemented in combination with hardware or software, or a combination thereof. Thus, the method and apparatus of the present invention, or some aspects or parts of the method and apparatus of the present invention can be embedded in a tangible medium, such as a floppy disk, a CD-ROM, a hard disk drive, or a program code (i.e., an instruction) in any other machine-readable storage medium, wherein when the program is loaded into a machine such as a computer and executed by the machine, the machine becomes a device for practicing the present invention.

[0035] In the case where the program code is executed on a programmable computer, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. The memory is configured to store the program code; the processor is configured to execute the method of the utility model according to the instructions in the program code stored in the memory.

[0036] By way of example and not limitation, computer readable media include computer storage media and communication media. Computer storage media stores information such as computer readable instructions, data structures, program modules or other data. Communication media generally embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and includes any information delivery media. Combinations of any of the above are also included within the scope of computer readable media.

[0037] As used herein, unless otherwise specified, the use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved, and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0038] Although the utility model has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the utility model described herein. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for the purpose of explaining or limiting the subject matter of the utility model. Therefore, many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the utility model is illustrative rather than restrictive with respect to the scope of the utility model, and the scope of the utility model is defined by the appended claims.

[0039] Finally, it should be noted that the present invention does not explain in detail the common knowledge recognized by technicians in this field. The above is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microwave photon broadband weak signal receiving device, characterized in that: It includes a directly modulated laser, an optically adjustable attenuator, a photodetector, a first amplifier, a first power divider, a spectrum analyzer, a second amplifier, a filter, and a second power divider; The directly modulated laser, the optical adjustable attenuator, the photodetector, the first amplifier, the first power divider, the second amplifier, the tunable filter and the second power divider are connected end to end in sequence to form a photoelectric oscillation loop; the two output ends of the first power divider are respectively connected to the second amplifier and the spectrum analyzer; the second power divider has an input end for receiving weak signals.

2. The microwave photon broadband weak signal receiving device according to claim 1, characterized in that: The first amplifier and the second amplifier are both narrowband microwave amplifiers.

3. The microwave photon broadband weak signal receiving device according to claim 1 or 2, characterized in that: The directly modulated laser is connected to the optical adjustable attenuator through a single-mode optical fiber.

4. The microwave photon broadband weak signal receiving device according to claim 1 or 2, characterized in that: It also includes a processor; the filter is an electrically controlled tunable filter, and the processor is communicatively connected with the electrically controlled tunable filter.

Images