A method and device suitable for long-distance transmission of wideband radio frequency signals

Abstract

A kind of method and device suitable for wideband radio frequency signal long-distance transmission, the wideband radio frequency signal long-distance transmission equipment is in 100MHz~6000MHz, both can send signal and can receive signal, by low noise amplifier, digital signal processing board, wave division multiplexer, wave division demultiplexer and band pass filter, optical amplifier unit, method suitable for wideband radio frequency signal long-distance transmission includes the signal processing steps of sending end and receiving end, solve the restriction of transmission signal to analog optical communication by optical fiber, can introduce larger noise and make signal distortion, the method and device suitable for wideband radio frequency signal long-distance transmission of the application can realize the long-distance transmission of radio frequency signal with 1GHz signal bandwidth in 100MHz~6000MHz frequency band, transmission distance is not less than 100km, not limited by the restriction of used optical fiber fusion, ensure the amplitude-frequency characteristic and phase characteristic of transmission signal.

Description

Technical fields:

[0001] This invention belongs to the field of electronic communication technology, and mainly relates to a method and apparatus suitable for long-distance transmission of broadband radio frequency signals. Background technology:

[0002] With the development of radar technology, the amount of information that needs to be transmitted between radar subsystems and between the radar and the command center has increased significantly. Furthermore, the types of signals have increased, transmission requirements have risen, and transmission distances have lengthened. As radar detection missions have evolved, radar transmission power has continuously increased, necessitating consideration of operator safety. Deploying multiple radar systems within the same reconnaissance station requires addressing electromagnetic compatibility issues between different devices and the mutual interference caused by different radar antenna shielding. In certain important and sensitive locations such as border islands, where long-term personnel deployment is unsuitable but radar detection missions are still required, it is advisable to deploy antennas externally while housing signal processing equipment in the reconnaissance and control station's control room. For these reasons, the need has arisen to separate the deployment of radar antennas from signal processing equipment.

[0003] When radio frequency (RF) signals are transmitted through the atmosphere, they are subject to multipath effects due to interference from various obstacles, resulting in signal fading. This fading degrades signal quality, and the signal characteristics cannot be recovered after long-distance transmission. RF signals transmitted via coaxial cable suffer from power loss, which is proportional to the transmission distance and signal frequency. The maximum transmission distance is limited to within a hundred meters, and the cable is easily monitored, offering poor security and high manufacturing costs, making it unsuitable for long-distance transmission of high-frequency RF signals. Optical fiber, on the other hand, offers advantages such as small size, light weight, and low cost. Furthermore, it features low transmission loss, wide bandwidth, and strong anti-interference capabilities. Therefore, using optical fiber to transmit broadband RF signals can significantly reduce system costs and ensure the phase characteristics of the signal after long-distance transmission.

[0004] Traditional communication systems widely use optical fibers for communication. However, analog optical communication is limited by the optical fiber used to transmit signals, introducing significant noise and causing signal distortion. Existing digital optical communication technologies cannot meet the requirements of distributed radar detection equipment regarding the phase characteristics and noise figure of transmitted signals. Therefore, existing communication systems cannot meet the long-distance transmission needs of broadband radio frequency signals for distributed radar. Summary of the Invention:

[0005] To achieve long-distance transmission of broadband radio frequency signals of at least 1 GHz and a transmission distance of at least 100 km, this invention provides a method and apparatus suitable for long-distance transmission of broadband radio frequency signals. When using this method to transmit broadband radio frequency signals, long-distance distortion-free transmission is achieved while ensuring the amplitude-frequency characteristics of the transmitted signal.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows:

[0007] A device for long-distance transmission of broadband radio frequency signals, comprising:

[0008] A low-noise amplifier is used to amplify received radio frequency signals with low noise.

[0009] A digital signal processing board is used to convert analog signals into digital signals or digital signals into analog signals.

[0010] A wavelength division multiplexer converts multiple optical signals into a single optical signal.

[0011] A dewavelength division multiplexer converts a single optical signal into multiple optical signals.

[0012] A bandpass filter is used for filtering signals.

[0013] Optical amplifier unit, used to amplify optical signals;

[0014] The broadband radio frequency signal long-distance transmission device operates in the frequency band of 100MHz to 6000MHz, and can both transmit and receive signals.

[0015] The digital signal processing board includes:

[0016] The A / D module performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal;

[0017] The digital downconverter module converts the digital signal from the A / D module into a baseband signal;

[0018] Digital filtering module, used for signal filtering;

[0019] The parallel-to-serial conversion data encoding module and high-speed serial port multiplex the filtered digital baseband signal and output it synchronously through 8 high-speed serial ports;

[0020] The electro-optical conversion module converts the digital signals synchronously output from the eight high-speed serial ports into eight optical signals.

[0021] The photoelectric conversion module converts 8 optical signals into 8 high-speed serial electrical signals.

[0022] The serial-to-parallel conversion data decoding module decodes the eight high-speed serial electrical signals and outputs one digital signal.

[0023] The digital up-conversion module performs frequency conversion on one digital signal output from the serial-to-parallel conversion data decoding module;

[0024] The D / A module converts high-speed digital signals into analog signals.

[0025] The A / D module has a sampling bit width of 14 bits and a clock frequency of 4Gbps. It uses broadband direct sampling technology to sample radio frequency signals with a bandwidth of 1GHz in the 100MHz to 6000MHz frequency band.

[0026] The D / A module has a bit width of 14 bits and a clock frequency of 4Gbps, and can recover digital signals to radio frequency signals with a bandwidth of 1GHz within the 100MHz to 6000MHz frequency band.

[0027] A method for long-distance transmission of broadband radio frequency signals, comprising the aforementioned long-distance broadband radio frequency signal transmission device, the method including signal processing steps at a transmitting end and a receiving end, wherein:

[0028] The steps at the sending end are as follows:

[0029] Step 1: After the RF signal is input, it is amplified by the low-noise amplifier of the broadband RF signal long-distance transmission equipment and then input to the A / D module of the digital signal processing board; Step 2: The A / D module of the digital signal processing board inside the broadband RF signal long-distance transmission equipment performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal;

[0030] Step 3: The sampled digital signal is digitally down-converted by the digital down-conversion module of the digital signal processing board to be converted into a baseband signal. The baseband signal is then filtered by the digital filtering module and output.

[0031] Step 4: The parallel-to-serial conversion data encoding module of the digital signal processing board multiplexes the filtered digital baseband signal and outputs it synchronously through 8 high-speed serial ports;

[0032] Step 5: The 8 high-speed serial digital signals are converted into 8 optical signals with wavelengths of λ1, λ2, λ3, λ4, λ5, λ6, λ7, and λ8 by the electro-optic conversion module; the clock generation module generates 1 clock signal and converts it into 1 optical signal with wavelength λ0 by electro-optic conversion.

[0033] Step 6: Convert the 9 optical signals into 1 optical signal using a wavelength division multiplexer for transmission;

[0034] Step 7: After wavelength division multiplexing, the nine optical signals of different wavelengths are multiplexed into one optical signal for output. After being amplified by the optical amplifier unit, the signal is transmitted to the remote end using a single-core optical fiber. According to the transmission distance and the loss of the optical fiber link, a repeater amplifier is placed in the middle of the optical fiber transmission link.

[0035] Receiving end steps:

[0036] Step 1: After receiving the optical signal, the remote radio frequency signal long-distance transmission equipment restores the 9 optical signals through the dewavelength division multiplexer, with wavelengths of λ0, λ1, λ2, λ3, λ4, λ5, λ6, λ7, and λ8.

[0037] Step 2: The eight optical signals with wavelengths λ1, λ2, λ3, λ4, λ5, λ6, λ7, and λ8 are converted into high-speed serial electrical signals by the electro-optical conversion module of the digital signal processing board; the optical signal with wavelength λ0 is recovered and used as the clock sampling signal for reception.

[0038] Step 3: The 8 high-speed serial electrical signals are decoded by the serial-to-parallel conversion data decoding module of the digital signal processing board, and output a 14-bit digital signal.

[0039] Step 4: The digital upconversion module of the digital signal processing board converts the 14-bit digital signal to a higher frequency and outputs it after filtering by the digital filtering module;

[0040] Step 5: The D / A module of the digital signal processing board converts the high-speed digital signal into an analog signal;

[0041] Step 6: The analog signal is amplified and then output;

[0042] Step 7: Users manually switch the back-end output filter according to the frequency band used to avoid signal mirroring interference between the A / D module and the D / A module.

[0043] Due to the adoption of the technical solution described above, the present invention has the following advantages:

[0044] The present invention provides a method and apparatus for long-distance transmission of broadband radio frequency signals, which can realize long-distance transmission of radio frequency signals with a bandwidth of 1GHz in the frequency band of 100MHz to 6000MHz, with a transmission distance of not less than 100km, without being limited by the fiber optic splicing used, and ensuring the amplitude-frequency characteristics and phase characteristics of the transmitted signal. Attached image description:

[0045] Figure 1 This is a schematic diagram of the radar and surveillance station equipment room layout after adopting radio frequency long-distance transmission;

[0046] Figure 2 A diagram showing the components of a long-distance radio frequency signal transmission device;

[0047] Figure 3 Flowchart for long-distance transmission and reception of broadband radio frequency signals;

[0048] Figure 4 This is a schematic diagram of a digital signal processing board;

[0049] Figure 5This is a flowchart of a long-distance transmission transmitter for broadband radio frequency signals;

[0050] Figure 6 This is a flowchart of a long-distance transmission and reception end for broadband radio frequency signals; Detailed implementation method:

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. (In conjunction with the accompanying drawings) Figure 2 The aforementioned device for long-distance transmission of broadband radio frequency signals includes: a low-noise amplifier 1.1, a digital signal processing board 1.2, a wavelength division multiplexer 1.3, a dewavelength division multiplexer 1.4, a bandpass filter 1.5, and an optical amplifier unit 1.6.

[0053] The low-noise amplifier 1.1 is used to amplify the received radio frequency signal with low noise.

[0054] The digital signal processing board 1.2 is used to convert analog signals into digital signals or digital signals into analog signals;

[0055] The wavelength division multiplexer 1.3 converts multiple optical signals into one optical signal.

[0056] The dewavelength division multiplexer converts one optical signal into multiple optical signals.

[0057] The bandpass filter 1.5 is used for signal filtering;

[0058] The optical amplifier unit 1.6 is used for amplifying optical signals;

[0059] The broadband radio frequency signal long-distance transmission device operates in the frequency band of 100MHz to 6000MHz, and can both transmit and receive signals.

[0060] The digital signal processing board 1.2 includes: an A / D module 1.2.1, a digital down-conversion module 1.2.2, a digital filtering module 1.2.3, a parallel-to-serial conversion data encoding module 1.2.4, a high-speed serial port 1.2.5, an electro-optical conversion module 1.2.6, a photoelectric conversion module 1.2.7, a serial-to-parallel conversion data decoding module 1.2.8, a digital up-conversion module 1.2.9, and a D / A module 1.2.10, realizing radio frequency signal sampling, digital filtering, data encoding, data decoding, photoelectric conversion, electro-optical conversion, digital-to-analog conversion, etc. Figure 4 As shown.

[0061] The A / D module 1.2.1 performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal;

[0062] The digital down-conversion module 1.2.2 converts the digital signal converted by the A / D module into a baseband signal;

[0063] The digital filtering module 1.2.3 is used for signal filtering;

[0064] The parallel-to-serial conversion data encoding module 1.2.4 and the high-speed serial port 1.2.5 multiplex the filtered digital baseband signal and output it synchronously through eight high-speed serial ports.

[0065] The electro-optical conversion module 1.2.6 converts the digital signals synchronously output from the 8 high-speed serial ports into 8 optical signals;

[0066] The photoelectric conversion module 1.2.7 converts 8 optical signals into 8 high-speed serial electrical signals;

[0067] The serial-to-parallel conversion data decoding module 1.2.8 decodes the eight high-speed serial electrical signals and outputs one digital signal.

[0068] The digital up-conversion module 1.2.9 performs frequency conversion on one digital signal output by the serial-to-parallel conversion data decoding module;

[0069] The D / A module 1.2.10 converts high-speed digital signals into analog signals.

[0070] The A / D module 1.2.1 has a sampling bit width of 14 bits and a clock frequency of 4Gbps. It uses broadband direct sampling technology to sample radio frequency signals with a signal bandwidth of 1GHz in the 100MHz to 6000MHz frequency band.

[0071] The D / A module 1.2.10 has a 14-bit width and a clock frequency of 4Gbps, capable of recovering digital signals to RF signals with a bandwidth of 1GHz within the 100MHz to 6000MHz frequency band. A method for long-distance transmission of broadband RF signals is provided, comprising the aforementioned long-distance broadband RF signal transmission device. The method includes signal processing steps at a transmitting end and a receiving end, wherein:

[0072] like Figure 5 As shown, the steps at the sending end are as follows:

[0073] Step 1: Deploy the radar antenna on a border island where it is unsuitable for long-term human presence, such as... Figure 1 As shown. The antenna's RF interface is connected to the RF signal transmitter port of the broadband RF signal long-distance transmission device via an RF cable. After the antenna receives the detection signal, the RF signal is input and then amplified by the low-noise amplifier 1.1 of the broadband RF signal long-distance transmission device before being input to the A / D module 1.2.1 of the digital signal processing board 1.2.

[0074] Step 2: The A / D module 1.2.1 of the internal digital signal processing board 1.2 of the broadband radio frequency signal long-distance transmission equipment performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal. The sampling clock frequency of the A / D module 1.2.1 is 4GHz, so the data volume of a single channel AD is calculated as: 4GHz * 14bit / Hz = 56Gbps; after the system's 64 / 66 encoding method, the data volume is: 56 / (64 / 66) = 57.75Gbps.

[0075] Step 3: The sampled digital signal is digitally down-converted by the digital down-conversion module 1.2.2 on the digital signal processing board 1.2 to be converted into a baseband signal. The baseband signal is then filtered by the digital filtering module 1.2.3 before being output.

[0076] Step 4: The parallel-to-serial conversion data encoding module 1.2.4 of the digital signal processing board 1.2 multiplexes the filtered digital baseband signal and outputs it synchronously through 8 high-speed serial ports 1.2.5, with a data rate of approximately 7.22Gbps.

[0077] Step 5: The 8 high-speed serial digital signals are converted into 8 optical signals with wavelengths of 1553.33nm, 1551.72nm, 1550.12nm, 1548.51nm, 1546.92nm, 1545.32nm, 1543.73nm, and 1542.14nm by the electro-optical conversion module 1. The clock generation module generates 1 clock signal and converts it into 1 optical signal with a wavelength of 1540.56nm by electro-optical conversion.

[0078] Step 6: In order to improve the efficiency of fiber optic utilization while taking into account the limited number of available fibers, it is necessary to convert the 9 optical signals into 1 optical signal for transmission through wavelength division multiplexer 1.3; when performing wavelength conversion, the optical module of digital signal processing board 1.2 should ensure that the wavelengths of all converted optical signals are within the operating wavelength range of optical amplifier unit 1.6.

[0079] Step 7: After wavelength division multiplexing, the nine optical signals of different wavelengths are multiplexed into one optical signal for output. After being amplified by optical amplifier unit 1.6, it is transmitted to the remote end through a single-core optical fiber. According to the transmission distance and the loss of the optical fiber link, a repeater amplifier is placed in the middle of the optical fiber transmission link.

[0080] like Figure 6 As shown, the receiving end steps are as follows:

[0081] Step 1: The radar signal processing equipment is deployed in the control station's equipment room, 100km away from the antenna, such as... Figure 1 As shown, the RF interface of the radar signal processing equipment is connected to the RF signal receiving port of the broadband RF signal long-distance transmission equipment via an RF cable. After receiving the optical signal, the remote RF signal long-distance transmission equipment uses a dewavelength division multiplexer 1.4 to restore nine optical signals with wavelengths of 1553.33nm, 1551.72nm, 1550.12nm, 1548.51nm, 1546.92nm, 1545.32nm, 1543.73nm, 1542.14nm, and 1540.56nm.

[0082] Step 2: Eight optical signals with wavelengths of 1553.33nm, 1551.72nm, 1550.12nm, 1548.51nm, 1546.92nm, 1545.32nm, 1543.73nm, and 1542.14nm are converted into high-speed serial electrical signals by the photoelectric conversion module 1.2.7 of the digital signal processing board 1.2; the optical signal with a wavelength of 1540.56nm is recovered and used as the clock sampling signal for reception. Step 3: The eight high-speed serial electrical signals are decoded by the serial-to-parallel conversion data decoding module 1.2.8 of the digital signal processing board 1.2, outputting one digital signal with a data bit width of 14 bits.

[0083] Step 4: The digital upconversion module of the digital signal processing board 1.2 converts the 14-bit digital signal to a higher frequency and outputs it after filtering by the digital filtering module 1.2.3;

[0084] Step 5: The D / A module 1.2.10 of the digital signal processing board 1.2 converts the high-speed digital signal into an analog signal;

[0085] Step 6: The analog signal is amplified and then output;

[0086] Step 7: The user manually switches the back-end output filter according to the frequency band used to avoid signal mirroring interference from A / D module 1.2.1 and D / A module 1.2.10.

[0087] This design enables long-distance transmission of radio frequency signals with a bandwidth of 1GHz within the 100MHz to 6000MHz frequency band, with a transmission distance of no less than 100km. It is not limited by the fiber optic splicing used and guarantees the amplitude-frequency and phase characteristics of the transmitted signal.

[0088] The parts not detailed above are existing technologies and therefore have not been described in detail.

Claims

1. A device suitable for long-distance transmission of broadband radio frequency signals, characterized in that: include A low-noise amplifier is used to amplify received radio frequency signals with low noise. A digital signal processing board is used to convert analog signals into digital signals or digital signals into analog signals. The digital signal processing board includes: The A / D module performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal; The digital downconverter module converts the digital signal from the A / D module into a baseband signal; Digital filtering module, used for signal filtering; The parallel-to-serial conversion data encoding module and high-speed serial port multiplex the filtered digital baseband signal and output it synchronously through 8 high-speed serial ports; The electro-optical conversion module converts the digital signals synchronously output from the eight high-speed serial ports into eight optical signals. The photoelectric conversion module converts 8 optical signals into 8 high-speed serial electrical signals. The serial-to-parallel conversion data decoding module decodes the eight high-speed serial electrical signals and outputs one digital signal. The digital up-conversion module performs frequency conversion on one digital signal output from the serial-to-parallel conversion data decoding module; A D / A module converts high-speed digital signals into analog signals; A wavelength division multiplexer converts nine different wavelength optical signals into one optical signal. A wavelength division multiplexer converts one optical signal into nine optical signals of different wavelengths. The nine different wavelengths include eight optical signals with wavelengths of 1553.33nm, 1551.72nm, 1550.12nm, 1548.51nm, 1546.92nm, 1545.32nm, 1543.73nm, and 1542.14nm, and one clock signal with a wavelength of 1540.56nm; A bandpass filter is used for filtering signals. Optical amplifier unit, used to amplify optical signals; The broadband radio frequency signal long-distance transmission device operates in the frequency band of 100MHz to 6000MHz, and can both transmit and receive signals. The broadband radio frequency signal long-distance transmission device adopts broadband direct sampling technology to achieve long-distance transmission of radio frequency signals with a signal bandwidth of 1GHz and a transmission distance of not less than 100km.

2. The device for long-distance transmission of broadband radio frequency signals according to claim 1, characterized in that: The A / D module has a sampling bit width of 14 bits and a clock frequency of 4Gbps. It uses broadband direct sampling technology to sample radio frequency signals with a bandwidth of 1GHz within the 100MHz~6000MHz frequency band.

3. The device for long-distance transmission of broadband radio frequency signals according to claim 1, characterized in that: The D / A module has a bit width of 14 bits and a clock frequency of 4Gbps, and can recover digital signals to radio frequency signals with a bandwidth of 1GHz within the 100MHz~6000MHz frequency band.

4. A method for long-distance transmission of broadband radio frequency signals, characterized in that: The method includes the broadband radio frequency signal long-distance transmission device according to any one of claims 1-3, wherein the method includes signal processing steps at a transmitting end and a receiving end, wherein: The steps at the sending end are as follows: Step 1: After the radio frequency signal is input, it is amplified by the low-noise amplifier of the broadband radio frequency signal long-distance transmission equipment and then input to the A / D module of the digital signal processing board. Step 2: The A / D module of the digital signal processing board inside the broadband radio frequency signal long-distance transmission equipment performs analog-to-digital conversion on the input analog signal, converting the analog signal into a digital signal; Step 3: The sampled digital signal is digitally down-converted by the digital down-conversion module of the digital signal processing board to be converted into a baseband signal. The baseband signal is then filtered by the digital filtering module and output. Step 4: The parallel-to-serial conversion data encoding module of the digital signal processing board multiplexes the filtered digital baseband signal and outputs it synchronously through 8 high-speed serial ports; Step 5: The 8-channel high-speed serial digital signals are converted into 8 channels with wavelengths of [wavelength value missing] by the electro-optical conversion module. Optical signal; the clock generation module generates one clock signal and converts it into one wavelength via electro-optical conversion. The optical signal; Step 6: Convert the 9 optical signals into 1 optical signal using a wavelength division multiplexer for transmission; Step 7: After wavelength division multiplexing, the nine optical signals of different wavelengths are multiplexed into one optical signal for output. After being amplified by the optical amplifier unit, it is transmitted to the remote end through a single-core optical fiber. According to the transmission distance and the loss of the optical fiber link, a repeater amplifier is placed in the middle of the optical fiber transmission link. Receiving end steps: Step 1: After receiving the optical signal, the remote radio frequency signal long-distance transmission equipment uses a demultiplexer to reconstruct 9 optical signals with wavelengths of [wavelength value missing]. ; Step 2: Wavelength is The eight optical signals are converted into high-speed serial electrical signals by the photoelectric conversion module of the digital signal processing board; the wavelength is The optical signal is recovered and used as the clock sampling signal for reception; Step 3: The 8 high-speed serial electrical signals are decoded by the serial-to-parallel conversion data decoding module of the digital signal processing board, and output a 14-bit digital signal. Step 4: The digital upconversion module of the digital signal processing board converts the 14-bit digital signal to a higher frequency and outputs it after filtering by the digital filtering module; Step 5: The D / A module of the digital signal processing board converts the high-speed digital signal into an analog signal; Step 6: The analog signal is amplified and then output; Step 7: Users manually switch the back-end output filter according to the frequency band used to avoid signal mirroring interference between the A / D module and the D / A module.

Images