Optical fiber transmission radio frequency signal phase correction method

Abstract

The invention belongs to the technical field of optical fiber transmission radio frequency signals, and relates to an optical fiber transmission radio frequency signal phase correction method comprising the following steps: an optical emission circuit converts a received radio frequency signal into a first optical signal, and transmits the first optical signal into an optical fiber; the power combiner forms a first radio-frequency signal from the received radio-frequency signal through a radio-frequency cable, and transmits the first radio-frequency signal to the first phase acquisition circuit; the optical fiber converts the received first optical signal into a second optical signal after passing through an uncertain temperature area, transmits the second optical signal to the optical receiving circuit, converts the second optical signal into a second radio frequency signal, and transmits the second radio frequency signal to the second phase acquisition circuit. A radio frequency cable is used as a phase reference to correct the phase change of multiple paths of optical fibers in the transmission process. The method combines the advantages of high phase stability of the radio frequency cable, small optical fiber size, light weight and strong anti-interference capability.

Description

Technical Field

[0001] The present application belongs to the technical field of using optical fiber to transmit radio frequency signals, and in particular, to a method for phase correction of optical fiber-transmitted radio frequency signals. Background Art

[0002] In the RF / microwave field, the main way to transmit RF signals is through RF cables. Although RF cables have good phase stability under different temperature environments, their physical structure determines that the insertion loss is large during long-distance transmission. In particular, when transmitting multiple RF signals, multiple RF cables are required. The diameter of each cable is at least 2mm, and they are large in size and heavy in weight, which limits the application of RF cables in miniaturized use scenarios.

[0003] At present, the technology of using light to transmit RF signals is advancing by leaps and bounds, especially in the miniaturized use scenarios of transmitting multiple RF signals. A single optical fiber can replace a single RF cable. The diameter of a single optical fiber is small, generally ranging from several microns to tens of microns, with a small size and light weight. At the same time, optical fiber also has excellent anti-interference capabilities, and the insertion loss is several orders of magnitude lower than that of RF cables. It has great advantages over RF cables in many fields.

[0004] Although optical fiber has the advantages mentioned above, due to the thermal expansion and contraction effect of optical fiber material, after the RF signal is converted into light and transmitted through the optical fiber, the phase of the signal will change greatly with temperature changes. When there are multiple optical fibers transmitting RF optical signals, if the multiple optical fibers are distributed in different locations, in different ambient temperatures, and have different temperature changes, the phase changes of each RF signal will be inconsistent, affecting the performance.

[0005] like Figure 1 As shown, when a multi-channel RF cable transmits RF signals, even if the location distribution, ambient temperature, and temperature change are different, the phase change of each RF signal can be ignored, and it does not affect the performance when used in engineering.

[0006] When the microwave signal source emits an RF signal with a phase of θ0, it is transmitted to the receiver 1 through the temperature zone 1. The phase difference of the RF signal after transmission through the RF cable is △θ=θ1-θ0, and △θ is very little affected by the temperature value and change of the temperature zone 1.

[0007] like Figure 2 As shown, if optical fiber is used to transmit radio frequency signals, the phase change of the radio frequency signal will be very large due to different optical fiber location distribution, different ambient temperature, and different temperature changes. If it is in a system with high requirements for phase, it may cause the system to malfunction.

[0008] When the RF signal of the microwave signal source is transmitted through the optical transmitter 1 to emit an optical signal with a phase of θ0, and then transmitted to the receiver 2 after passing through the temperature zone 2, since the optical fiber is highly sensitive to temperature changes, the greater the temperature difference in the temperature zone 2, the greater the deviation between θ3 and θ2; if the temperature change in the temperature zone 2 is irregular, then the difference between θ3 and θ2 will also be an irregular value.

[0009] Therefore, the fact that optical fiber transmission is greatly affected by temperature is a problem that needs to be solved. Summary of the invention

[0010] The purpose of the present application is to provide a method for phase correction of radio frequency signals transmitted by optical fiber, so as to solve the disadvantage in the prior art that the phase is greatly affected by temperature changes in the transmission path during optical fiber transmission.

[0011] The technical solution of the present application is: a method for phase correction of optical fiber transmission radio frequency signals, comprising:

[0012] Combining RF cables with fiber optic transmission lines to form a bundle of cables;

[0013] After receiving the microwave signal from the microwave signal source, the power splitter splits the power into two RF signals, one of which is transmitted to the optical transmitting circuit and the other is transmitted to the power combiner.

[0014] The optical transmitting circuit converts the received radio frequency signal into a first optical signal, and transmits the first optical signal into the optical fiber; the power combiner converts the received radio frequency signal into a first radio frequency signal through a radio frequency cable, and transmits the first radio frequency signal to the first phase acquisition circuit;

[0015] The optical fiber converts the received first optical signal into a second optical signal after passing through the uncertain temperature region, and transmits the second optical signal to the optical receiving circuit, and converts the second optical signal into a second radio frequency signal and transmits the second radio frequency signal to the second phase acquisition circuit;

[0016] The first phase acquisition circuit acquires the phase of the first radio frequency signal to form a first phase value; the second phase acquisition circuit acquires the phase of the second radio frequency signal to form a second phase value; the first phase value and the second phase value are sent to the digital processing circuit, and the second phase acquisition circuit sends the second radio frequency signal to the radio frequency signal processing circuit;

[0017] The digital processing circuit calculates a difference between the first phase value and the second phase value, and transmits the difference to the radio frequency signal processing circuit;

[0018] The radio frequency signal processing circuit performs phase compensation on the second radio frequency signal according to the difference between the first phase value and the second phase value to obtain a radio frequency signal with an accurate phase.

[0019] Preferably, the optical fiber, the second phase acquisition circuit and the RF signal processing circuit are each in multiple groups and connected correspondingly, each group of optical fibers can transmit different first optical signals, and each group of second phase acquisition circuits acquires the phase of different second RF signals; the digital acquisition circuit respectively calculates the phase difference between the second phase and the first phase of different second RF signals, and transmits them to the corresponding RF signal processing circuits respectively.

[0020] Preferably, the microwave signal source, power divider, power combiner and optical transmitting circuit are in the same temperature region; the optical receiving circuit, the first phase acquisition circuit, the second phase acquisition circuit, the digital processing circuit and the radio frequency signal processing circuit are in the same temperature region.

[0021] Preferably, in the bundle of cables, there are one or more radio frequency cables and one or more optical fiber transmission lines.

[0022] Preferably, the radio frequency cable and the optical fiber transmission line are arranged in parallel.

[0023] Preferably, the optical fiber transmission line is arranged in a spiral winding manner around the axis of the radio frequency cable.

[0024] Preferably, the cross-section of the bundle of cables is circular, elliptical, square, rectangular, triangular, rhombus, regular polygon, trapezoid or polygonal.

[0025] Preferably, the outer sides of the radio frequency cable and the optical fiber transmission line include shielding materials.

[0026] The method for phase correction of radio frequency signals transmitted by optical fiber of the present application uses radio frequency cables as phase references to correct phase changes of multiple optical fibers during transmission. This method combines the advantages of high phase stability of radio frequency cables, small size, light weight, and strong anti-interference ability of optical fibers. It can be applied to the fields of radio frequency optical transmission such as airborne / missile-borne, and can also be used in other fields that transmit radio frequency signals through optical fibers and have high requirements for phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0028] Figure 1 It is a process diagram of radio frequency signal transmission through radio frequency cable in the background technology;

[0029] Figure 2 It is a process diagram of optical fiber transmission of radio frequency signals in the background technology;

[0030] Figure 3 This is the overall transmission flow chart of this application.

[0031] 1. First phase acquisition circuit; 2. Second phase acquisition circuit. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] A method for phase correction of a radio frequency signal transmitted by an optical fiber comprises the following steps:

[0034] Step S100, combining a radio frequency cable and an optical fiber transmission line to form a bundle of cables, so that the cable has the characteristics of both radio frequency cables and optical fiber transmission lines. In a bundle of cables, there are one or more radio frequency cables and one or more optical fiber transmission lines.

[0035] Preferably, the radio frequency cable and the optical fiber transmission line are arranged in parallel, or the optical fiber transmission line is arranged in a spiral winding manner around the axis of the radio frequency cable to adapt to different working environments.

[0036] The cross-section of a bundle of cables is circular, elliptical, square, rectangular, triangular, rhombus, regular polygon, trapezoid and polygonal, allowing for flexible configuration.

[0037] Preferably, the outside of the radio frequency cable and the optical fiber transmission line includes shielding materials to improve electromagnetic shielding; thermal insulation materials can also be provided to improve the temperature consistency of the cable and reduce the impact of temperature changes on cable performance; shielding materials and thermal insulation materials can also be provided at the same time.

[0038] In step S200, after receiving the microwave signal emitted by the microwave signal source, the power divider divides the power into two radio frequency signals, one of which is transmitted to the optical transmitting circuit and the other is transmitted to the power combiner.

[0039] In step S300, the optical transmitting circuit converts the received RF signal into a first optical signal, and transmits the first optical signal into the optical fiber; the power combiner converts the received RF signal into a first RF signal through a RF cable, and transmits the first RF signal to the first phase acquisition circuit 1.

[0040] In step S400, the optical fiber converts the received first optical signal into a second optical signal after passing through the uncertain temperature region, and transmits the second optical signal to the optical receiving circuit, and converts the second optical signal into a second radio frequency signal and transmits the second radio frequency signal to the second phase acquisition circuit 2.

[0041] Preferably, there are multiple groups of optical fibers, second phase acquisition circuits 2 and RF signal processing circuits and they are connected accordingly, each group of optical fibers can transmit different first optical signals, and each group of second phase acquisition circuits 2 collects different phases of second RF signals; the digital acquisition circuits respectively calculate the phase difference between the second phase and the first phase of different second RF signals, and transmit them to the corresponding RF signal processing circuits respectively.

[0042] Preferably, the microwave signal source, the power divider, the power combiner and the optical transmitting circuit are in the same temperature region; the optical receiving circuit, the first phase acquisition circuit 1, the second phase acquisition circuit 2, the digital processing circuit and the radio frequency signal processing circuit are in the same temperature region, thereby eliminating temperature interference between the various components, and the temperatures in different temperature regions can be different.

[0043] Step S500: the first phase acquisition circuit 1 acquires the phase of the first RF signal to form a first phase value; the second phase acquisition circuit 2 acquires the phase of the second RF signal to form a second phase value; the first phase value and the second phase value are sent to the digital processing circuit, and the second phase acquisition circuit 2 sends the second RF signal to the RF signal processing circuit.

[0044] In step S600, the digital processing circuit calculates a difference between the first phase value and the second phase value, and transmits the difference to the radio frequency signal processing circuit.

[0045] Step S700: The radio frequency signal processing circuit performs phase compensation on the second radio frequency signal according to the difference between the first phase value and the second phase value to obtain a radio frequency signal with an accurate phase.

[0046] Through the above design, this application has the following advantages:

[0047] The RF cable is used as a phase reference to correct the phase changes of multiple optical fibers during transmission. This method combines the advantages of high phase stability of RF cables and small size, light weight and strong anti-interference ability of optical fibers. It can be applied to RF optical transmission fields such as airborne / missile-borne, as well as other fields that transmit RF signals through optical fibers and have high requirements for phase.

[0048] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to common designs. In the absence of conflicts, the same embodiment and different embodiments of the present invention can be combined with each other;

[0049] Finally: The above description is only a preferred 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 method for phase correction of optical fiber transmission radio frequency signals, characterized in that: include: Combining RF cables with fiber optic transmission lines to form a bundle of cables; After receiving the microwave signal from the microwave signal source, the power splitter splits the power into two RF signals, one of which is transmitted to the optical transmitting circuit and the other is transmitted to the power combiner. The optical transmitting circuit converts the received radio frequency signal into a first optical signal, and transmits the first optical signal into the optical fiber; the power combiner converts the received radio frequency signal into a first radio frequency signal through a radio frequency cable, and transmits the first radio frequency signal to a first phase acquisition circuit (1); The optical fiber converts the received first optical signal into a second optical signal after passing through the uncertain temperature region, and transmits the second optical signal to the optical receiving circuit, and converts the second optical signal into a second radio frequency signal and transmits the second radio frequency signal to the second phase acquisition circuit (2); The first phase acquisition circuit (1) acquires the phase of the first radio frequency signal to form a first phase value; the second phase acquisition circuit (2) acquires the phase of the second radio frequency signal to form a second phase value; the first phase value and the second phase value are sent to the digital processing circuit, and the second phase acquisition circuit (2) sends the second radio frequency signal to the radio frequency signal processing circuit; The digital processing circuit calculates a difference between the first phase value and the second phase value, and transmits the difference to the radio frequency signal processing circuit; The radio frequency signal processing circuit performs phase compensation on the second radio frequency signal according to the difference between the first phase value and the second phase value to obtain a radio frequency signal with an accurate phase.

2. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The optical fiber, the second phase acquisition circuit (2) and the radio frequency signal processing circuit are each provided in multiple groups and are connected correspondingly, each group of optical fibers can transmit different first optical signals, and each group of second phase acquisition circuits (2) acquires the phase of different second radio frequency signals; the digital acquisition circuits respectively calculate the phase difference between the second phase and the first phase of different second radio frequency signals, and transmit them to the corresponding radio frequency signal processing circuits respectively.

3. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The microwave signal source, the power divider, the power combiner and the optical transmission circuit are in the same temperature region; the optical receiving circuit, the first phase acquisition circuit (1), the second phase acquisition circuit (2), the digital processing circuit and the radio frequency signal processing circuit are in the same temperature region.

4. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: In the bundle of cables, there are one or more radio frequency cables and one or more optical fiber transmission lines.

5. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The radio frequency cable is arranged in parallel with the optical fiber transmission line.

6. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The optical fiber transmission line is arranged around the axis of the radio frequency cable in a spiral winding manner.

7. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The cross section of the bundle of cables is circular, elliptical, square, rectangular, triangular, rhombus, regular polygon, trapezoid and polygon.

8. The method for ensuring the phase of a radio frequency signal transmitted by an optical fiber according to claim 1, characterized in that: The outer sides of the radio frequency cable and the optical fiber transmission line include shielding materials.

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