Radio frequency front-end transmitting link and state detection method thereof

Abstract

The invention relates to a radio frequency front-end transmitting link and a state detection method thereof, the transmitting link adopts four-stage series power amplification circuits, and the four-stage series power amplification circuits comprise a first-stage power amplification circuit, a second-stage power amplification circuit, a third-stage power amplification circuit and a fourth-stage power amplification circuit; the first-stage power amplification circuit is composed of a first pi attenuator and a low-noise amplification chip and used for radio frequency small signal gain amplification. The second-stage power amplification circuit is formed by cascading a temperature compensation attenuator, a filter and a gallium arsenide power amplifier tube, and the filter is a broadband filter, a tuned filter or a frequency hopping filter; the third-stage power amplification circuit is formed by cascading a numerical control attenuator and a three-stage gallium nitride power amplifier tube; and the fourth-stage power amplification circuit is formed by cascading a second pi-type attenuator and a last-stage gallium nitride power amplifier tube. The method has the advantages of being high in dynamic range and good in adaptability in a software radio system.

Description

[Technical field]

[0001] The present invention relates to the field of radio frequency front-end technology, and in particular to a radio frequency front-end transmission link and a state detection method thereof. [Background technology]

[0002] With the development of software radio technology, especially the advancement of computer software and artificial intelligence technology, tactical communications, electronic countermeasures and other equipment have the ability to be software programmable and hardware reconfigurable. In terms of hardware, the software radio system hardware is required to adopt a modular design, and the baseband module, RF transceiver module, RF front-end module, antenna and other components have the ability to be quickly assembled and flexibly adapted. In terms of software, the waveform application of the software radio system is required to be decoupled from the underlying hardware, and different waveform applications can be quickly switched according to the needs of the scene, and have the ability to self-diagnose and adjust.

[0003] However, the traditional RF front-end transmitter link is designed for specific scenarios and requirements, and mainly faces the following problems:

[0004] First, the transmit link has poor adjustability, a small dynamic range of transmit power, and poor compatibility with front-end and back-end components (antenna, RF transceiver module);

[0005] Second, the degree of digitization is low and the status detection method is single, which cannot meet the needs of improving the capabilities of the transmission link, such as intelligent power control, linearity optimization, and efficiency improvement.

[0006] The present invention aims at the technical problems of poor adjustable capability of the transmission link, low digitization degree and single state detection means in the prior art, and makes technical improvements to the radio frequency front-end transmission link and its state detection method. [Summary of the invention]

[0007] The purpose of the present invention is to provide a radio frequency front-end transmission link with high dynamic range and good adaptability in a software radio system.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a radio frequency front-end transmission link, which receives a small radio frequency signal from a rear-end transmission channel module and feeds back the radio frequency signal at the output end to the rear-end transmission channel module; the front end of the transmission link is connected to an antenna to send the radio frequency signal to an air interface; the transmission link adopts a four-stage series power amplifier circuit to process and amplify the small radio frequency signal step by step; the four-stage series power amplifier circuit includes a first-stage power amplifier circuit, a second-stage power amplifier circuit, a third-stage power amplifier circuit, a fourth-stage power amplifier circuit, a three-port qualitative coupler and a four-port qualitative coupler; the first-stage power amplifier circuit is composed of a first π attenuator and a low-noise amplifier chip, which is used for transmitting small radio frequency signals. The signal gain is amplified; the second-stage power amplifier circuit is composed of a temperature-compensated attenuator, a filter, and a gallium arsenide power amplifier tube in cascade, and the filter is a broadband filter, a tuning filter, or a frequency-hopping filter; the third-stage power amplifier circuit is composed of a digitally controlled attenuator and a three-stage gallium nitride power amplifier tube in cascade; the fourth-stage power amplifier circuit is composed of a second π-type attenuator and a final-stage gallium nitride power amplifier tube in cascade; the final-stage gallium nitride power amplifier tube is connected to the first port of the three-port qualitative coupler, the second port of the three-port qualitative coupler feeds the radio frequency signal back to the back-end transmission channel module, the third port of the three-port qualitative coupler is connected to the first port of the four-port qualitative coupler, and the fourth port of the four-port qualitative coupler is connected to the antenna.

[0009] Preferably, the RF front-end transmission link also includes a transmission link management module, a power supply control circuit, a transmission power and standing wave detection circuit; the power supply control circuit is used to control the power switch of the four-stage series power amplifier circuit; the transmission power and standing wave detection circuit is used to perform transmission power and standing wave detection on the RF signal output by the four-stage series power amplifier circuit; the transmission link management module is composed of a microprocessor and peripheral circuits, and is used for the transmission link status detection, transmission link control, and transmission link status and alarm information reporting.

[0010] Preferably, the transmission power and standing wave detection circuit is composed of a four-port coupler, a first attenuator, a second attenuator, a first logarithmic power detector, and a second logarithmic power detector, wherein the first attenuator and the second attenuator are π-type attenuators; the second port of the four-port qualitative coupler is connected to the first coupling port of the four-port coupler, and the third port of the four-port qualitative coupler is connected to the second coupling port of the four-port coupler; the first isolation port of the four-port coupler is connected to the input end of the first attenuator, and the second isolation port of the four-port coupler is connected to the input end of the second attenuator; the output end of the first attenuator is connected to the first logarithmic power detector, and the output end of the second attenuator is connected to the second logarithmic power detector.

[0011] Preferably, the transmission link management module includes a first power amplifier control interface and a second power amplifier control interface; the power control circuit includes a first power modulation chip with a built-in NMOS switch tube, which is used to receive a switch control signal from the first power amplifier control interface of the transmission link management module to provide power input for the first-stage power amplifier and the first-stage power amplifier; the power control circuit also includes a second power modulation chip with an internally integrated negative voltage enable function and an input connected to the gate of the PMOS switch tube, which is used to receive a switch control signal from the second power amplifier control interface of the transmission link management module to provide power input for the third-stage power amplifier and the fourth-stage power amplifier.

[0012] Preferably, the transmission link management module also includes a temperature detection interface and a temperature sensor, the temperature sensor is arranged near the final gallium nitride power amplifier tube, and the temperature detection interface is connected to the temperature sensor for reading the temperature of the transmission link; the transmission link management module also includes an input signal power interface, which is connected to the first logarithmic power detector and the second logarithmic power detector; the transmission link management module also includes a positive voltage detection interface and a reverse voltage detection interface, the positive voltage detection interface is connected to the four-port coupler coupling port, and the reverse voltage detection interface is connected to the four-port coupler isolation port; the transmission link management module also includes an attenuator control port, and the attenuator control port is connected to the digitally controlled attenuator; the transmission link management module also includes a serial port for reporting the transmission link status and alarm information.

[0013] Another object of the present invention is to provide a method for detecting the state of a radio frequency front-end transmission link with high dynamic range and good adaptability in a software radio system.

[0014] To achieve the above-mentioned further object, the technical solution adopted by the present invention is a method for detecting the state of a radio frequency front-end transmission link, based on the above-mentioned radio frequency front-end transmission link, comprising the following steps:

[0015] S1, read the configuration parameters input from the outside, including the detection period, standing wave ratio threshold Thr1 and Thr2, power alarm threshold, mismatch alarm threshold, over-temperature threshold Temp1 and Temp2, and adjustment step value, where Temp1 <Temp2,Thr1<Thr2;

[0016] S2, read the temperature sensor value of the current detection cycle, average it with the temperature sensor values ​​of the previous two detection cycles to get the average temperature, and then compare it with the over-temperature threshold. When the temperature average value is greater than Temp1 and less than Temp2, adjust the digital attenuator to reduce 1 adjustment step value; when the temperature average value is greater than Temp2, immediately shut down the gallium arsenide power amplifier tube and the three-stage gallium nitride power amplifier tube; when the temperature average value is less than Temp1, work normally;

[0017] S3, read the transmission power and the two positive and reverse output voltages of the standing wave detection circuit, and calculate the standing wave ratio Vswr, the RF output signal power, and the return loss value respectively through the standing wave ratio and return loss calculation formulas;

[0018] When the standing wave ratio Vswr is less than or equal to the standing wave ratio threshold Thr1, it works normally; when the standing wave ratio Vswr is between Thr1 and Thr2, the digital controlled attenuator is adjusted to reduce 1 adjustment step value; when the standing wave ratio Vswr is greater than Thr2, the gallium arsenide power amplifier tube, the three-stage gallium nitride power amplifier tube, and the final-stage gallium nitride power amplifier tube are immediately turned off;

[0019] S4, read the RF small signal input signal power, calculate the transmission link gain, and obtain the transmission link efficiency;

[0020] S5. Record and report the temperature sensor value, standing wave ratio, input signal power, output signal power, power amplifier switch state, transmission link efficiency, and transmission link gain obtained in the current detection cycle through the serial port, and estimate how many detection cycle transmission link state values ​​can meet the configuration parameter requirements.

[0021] The invention discloses a radio frequency front-end transmission link and a state detection method thereof, which have the following beneficial effects: 1. The adoption of a multi-stage GaAs power amplifier tube, a GaN power amplifier tube cascade, a digitally controlled attenuator, and a temperature-controlled attenuator ensures the gain dynamic range of the transmission link and has a certain inhibitory effect on the linear distortion of the transmission link; 2. By real-time detection of temperature changes, standing wave ratio, return loss and other states, the health state of the transmission link is timely diagnosed. When an abnormal situation occurs, the transmission link will self-adjust the attenuation and shut down the power amplifier tube in time to prevent damage to the high-power amplifier due to factors such as antenna open circuit, short circuit, overheating, etc.; 3. The transmission link periodically collects state information such as the link temperature, transmission efficiency, link gain, standing wave ratio, etc., and reports it to the superior management module, which is helpful for health data analysis of the radio frequency front end and improves the system fault prediction capability.

Brief Description of the Drawings

[0022] Figure 1 This is a diagram of the RF front-end transmission link structure.

[0023] Figure 2 It is a schematic diagram of the transmitting power and standing wave detection circuit.

[0024] Figure 3 It is a schematic diagram of the RF front-end transmission link management module.

[0025] Figure 4 It is a schematic diagram of the transmission link status detection and processing flow. [Specific implementation method]

[0026] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present invention. But it is obvious to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific configuration and algorithm proposed below, but covers any modification, replacement and improvement of elements, parts and algorithms without departing from the concept of the present invention. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity to the present invention.

[0027] Example

[0028] This embodiment implements a transmission link design method with a high dynamic range and integrates multiple state detection methods.

[0029] This embodiment aims to propose a transmission link design method with a high dynamic range and integrate multiple state detection methods to improve the adaptability of the transmission link of the radio frequency front end in the software radio system.

[0030] Figure 1 This is the diagram of the RF front-end transmission link. Figure 1 As shown, this embodiment proposes a design method for a radio frequency front-end transmission link adapted to a software radio architecture. The radio frequency chain is mainly composed of a filtering and amplifying link, a transmission link management module, a power supply control circuit, a transmission power and a standing wave detection circuit. Receive a small radio frequency signal from a back-end transmission channel module, and feed back the radio frequency signal at the output end to the back-end transmission channel module. The front end of the transmission link is connected to an antenna for sending the radio frequency signal to the air interface.

[0031] The signal transmission link (filtering and amplification link) of the RF front end adopts a four-stage power amplification process, each stage of the power amplifier is connected in series, and the signal is amplified step by step. The first stage amplifier circuit is composed of a π attenuator and a low-noise amplifier chip, which plays a role in small signal gain amplification; the second stage amplifier circuit is composed of a temperature-compensated attenuator, a filter, and a gallium arsenide (GaAs) power amplifier tube cascade, wherein the filter can be selected according to actual needs. The type includes a broadband filter, a tuning filter, and a frequency hopping filter; the third stage amplifier circuit is composed of a digitally controlled attenuator and a gallium nitride (GaN) power amplifier tube cascade; the fourth stage amplifier circuit is composed of a π-type attenuator and a final-stage GaN power amplifier tube cascade. In addition, the final-stage power amplifier tube is connected to a coupler 1, and the coupler uses a 3-port qualitative coupler. Coupler 1 is connected to coupler 2, wherein coupler 2 uses a 4-port qualitative coupler. The model selection of the coupler can be selected according to the insertion loss, working bandwidth, coupling coefficient and other indicators of the coupler.

[0032] The power control circuit is mainly used to control the power switch of the above-mentioned four-stage amplifier and the detection of voltage and current. Among them, the first-stage low-noise amplifier is powered by a +5V power supply, the second-stage GaAs power amplifier tube is powered by a +12V power supply, and the third-stage and final-stage power amplifier tubes are powered by a +28V power supply. A power modulation chip 1 with a built-in NMOS switch tube with a fast switching rate is selected to provide +5V and +12V power inputs for the first-stage low-noise amplifier and the second-stage GaAs power amplifier tube, respectively, and receive a switch control signal from the link management module. The power modulation chip 2 uses a device with an internal integrated negative voltage enabling function that supports a maximum of 32V. The input of the power modulation chip 2 is connected to the gate of the PMOS switch tube, and receives a switch control signal from the link management module to control the third-stage and final-stage GaN power amplifier tubes.

[0033] Figure 2 This is a schematic diagram of the transmission power and standing wave detection circuit. Figure 2 As shown, the transmission power and standing wave detection circuit is mainly composed of 1 coupler, 2 attenuators, and 2 logarithmic detectors, wherein the coupler is a 4-port coupler. In the four-port configuration, the input port points to the coupling port, indicating that it receives the forward component, and the output port is connected to the isolation port, which is used to read the reflected signal. The attenuator is a π-type attenuator. The detector is a logarithmic power detector to realize the detection of forward output power and reflected power. The dynamic range and operating frequency of the detector are determined according to specific needs.

[0034] Figure 3 Figure 1 is a schematic diagram of the RF front-end transmission link management module. Figure 3 As shown, the transmission link management module is mainly composed of a microprocessor and peripheral circuits, providing functions such as transmission link status detection, link control and status information reporting. The management module provides 2 power detection interfaces, which are respectively connected to the 12V power chip and the 28V power chip; provides 2 power amplifier control interfaces, which are respectively connected to the power modulation chip 1 and the power chip modulation 2. The first power amplifier tube control interface is used for switching control of the first and second power amplifier tubes, and the second power amplifier tube control interface is used for switching control of the third and final power amplifier tubes. The temperature detection interface is used to read the temperature of the RF transmission link circuit, and the sensor is arranged at the highest temperature point of the RF link (usually near the final power amplifier tube). Provide 1 input signal power interface, connected to the first detector of the transmission link. Provide 2 positive and negative voltage detection interfaces of the coupler, which are respectively connected to the isolation port and coupling port of the 4-port directional coupler 2. Provide 1 attenuator control port, connected to the digital control attenuator. Provide 1 serial port, connected to the system-level control management unit, for reporting status information and alarm information.

[0035] Figure 4 Figure 1 is a schematic diagram of the transmission link status detection and processing flow. Figure 4 The specific working steps are described as follows:

[0036] Step 1: Read the configuration parameters input from the outside, including the detection period, standing wave ratio alarm threshold, power alarm threshold, mismatch alarm threshold, over-temperature threshold, over-temperature adjustment step value, etc., read the parameters and set them in the processing algorithm.

[0037] Step 2: Read the temperature sensor value of the current cycle and smooth it with the temperature values ​​of the previous two cycles, that is, calculate the average. Then compare it with the over-temperature threshold and set two over-temperature thresholds Temp1 and Temp2. ​​When the temperature is greater than Temp1 and less than Temp2, reduce the step value by adjusting the digital attenuator. When the temperature is greater than Temp2, immediately shut down the second and third stage power amplifier tubes, otherwise it is considered normal.

[0038] Step 3: Read the two positive and reverse output voltages of the standing wave and power detection circuit, and calculate the standing wave ratio Vswr, output power Pt (in dBm), and return loss value respectively through the standing wave ratio and return loss calculation formulas.

[0039] For the standing wave ratio abnormality processing flow, when the power amplifier output Vswr is less than or equal to the standing wave ratio threshold Thr1, the power amplifier works normally; when the output Vswr is between Thr1 and Thr2, the digital control attenuation value is reduced by 1 step value; when the output Vswr is greater than Thr2, the power amplifier is immediately turned off to protect it.

[0040] Step 4: Link gain and efficiency calculation. Read the RF signal input power Pin and calculate the link approximate gain value Pin-Pt. The efficiency calculation process is described as follows:

[0041] First, read the power P1 and P2 of the 12V power supply and the 28V power supply respectively, and calculate the total power output power Psrc=P1+P2; secondly, convert the link output power Pt value to Ps (in W); finally, calculate the efficiency value of the link as (Ps / Psrc)*100%.

[0042] Step 5: Send the temperature value, standing wave ratio, input signal power, output signal power, power amplifier switch status, link efficiency, link gain and other values ​​obtained in this detection cycle to the upper control management module through the serial port. And record the status value of the current cycle locally. The maximum number of cycle status values ​​recorded locally can be set by parameters.

[0043] Those skilled in the art will appreciate that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, wherein the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the principle of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A radio frequency front-end transmission link, which receives a small radio frequency signal from a rear-end transmission channel module and feeds back the radio frequency signal at the output end to the rear-end transmission channel module; the front end of the transmission link is connected to an antenna to send the radio frequency signal to an air interface; characterized in that: The transmitting link adopts a four-stage series power amplifier circuit to process and amplify the small radio frequency signal step by step; the four-stage series power amplifier circuit includes a first-stage power amplifier circuit, a second-stage power amplifier circuit, a third-stage power amplifier circuit, a fourth-stage power amplifier circuit, a three-port qualitative coupler and a four-port qualitative coupler; the first-stage power amplifier circuit is composed of a first π attenuator and a low-noise amplifier chip, which is used for small radio frequency signal gain amplification; the second-stage power amplifier circuit is composed of a temperature-compensated attenuator, a filter, and a gallium arsenide power amplifier tube in cascade, and the filter is a broadband filter, tuned filter, or frequency hopping filter; the third-stage power amplifier circuit is composed of a digitally controlled attenuator and a three-stage gallium nitride power amplifier tube cascade; the fourth-stage power amplifier circuit is composed of a second π-type attenuator and a final-stage gallium nitride power amplifier tube cascade; the final-stage gallium nitride power amplifier tube is connected to the first port of the three-port qualitative coupler, the second port of the three-port qualitative coupler feeds back the radio frequency signal to the back-end transmission channel module, the third port of the three-port qualitative coupler is connected to the first port of the four-port qualitative coupler, and the fourth port of the four-port qualitative coupler is connected to the antenna.

2. The radio frequency front-end transmission link according to claim 1, characterized in that: It also includes a transmission link management module, a power supply control circuit, a transmission power and standing wave detection circuit; the power supply control circuit is used to control the power switch of the four-stage series power amplifier circuit; the transmission power and standing wave detection circuit is used to perform transmission power and standing wave detection on the radio frequency signal output by the four-stage series power amplifier circuit; the transmission link management module is composed of a microprocessor and peripheral circuits, and is used for the transmission link status detection, transmission link control, and transmission link status and alarm information reporting.

3. A radio frequency front-end transmission link according to claim 2, characterized in that: The transmission power and standing wave detection circuit is composed of a four-port coupler, a first attenuator, a second attenuator, a first logarithmic power detector, and a second logarithmic power detector. The first attenuator and the second attenuator are π-type attenuators; the second port of the four-port qualitative coupler is connected to the first coupling port of the four-port coupler, and the third port of the four-port qualitative coupler is connected to the second coupling port of the four-port coupler; the first isolation port of the four-port coupler is connected to the input end of the first attenuator, and the second isolation port of the four-port coupler is connected to the input end of the second attenuator; the output end of the first attenuator is connected to the first logarithmic power detector, and the output end of the second attenuator is connected to the second logarithmic power detector.

4. The radio frequency front-end transmission link according to claim 3, characterized in that: The transmission link management module includes a first power amplifier control interface and a second power amplifier control interface; the power control circuit includes a first power modulation chip with a built-in NMOS switch tube, which is used to receive a switch control signal from the first power amplifier control interface of the transmission link management module to provide power input for the first-stage power amplifier and the first-stage power amplifier; the power control circuit also includes a second power modulation chip with an internally integrated negative voltage enabling function and an input connected to the gate of the PMOS switch tube, which is used to receive a switch control signal from the second power amplifier control interface of the transmission link management module to provide power input for the third-stage power amplifier and the fourth-stage power amplifier.

5. The radio frequency front-end transmission link according to claim 4, characterized in that: The transmission link management module also includes a temperature detection interface and a temperature sensor, wherein the temperature sensor is arranged near the final-stage gallium nitride power amplifier tube, and the temperature detection interface is connected to the temperature sensor for reading the temperature of the transmission link; the transmission link management module also includes an input signal power interface, which is connected to the first logarithmic power detector and the second logarithmic power detector; The transmission link management module further includes a positive voltage detection interface and a reverse voltage detection interface, wherein the positive voltage detection interface is connected to the coupling port of the four-port coupler, and the reverse voltage detection interface is connected to the isolation port of the four-port coupler; The transmit link management module further includes an attenuator control port, wherein the attenuator control port is connected to the digitally controlled attenuator; The transmission link management module also includes a serial port for reporting transmission link status and alarm information.

6. A method for detecting the state of a radio frequency front-end transmission link, based on the radio frequency front-end transmission link of claim 5, characterized in that The following steps are involved: S1, read the configuration parameters input from the outside, including the detection period, standing wave ratio threshold Thr1 and Thr2, power alarm threshold, mismatch alarm threshold, over-temperature threshold Temp1 and Temp2, and adjustment step value, where Temp1 <Temp2,Thr1<Thr2; S2, read the temperature sensor value of the current detection cycle, average it with the temperature sensor values ​​of the previous two detection cycles to get the average temperature, and then compare it with the over-temperature threshold. When the temperature average value is greater than Temp1 and less than Temp2, adjust the digital attenuator to reduce 1 adjustment step value; when the temperature average value is greater than Temp2, immediately shut down the gallium arsenide power amplifier tube and the three-stage gallium nitride power amplifier tube; when the temperature average value is less than Temp1, work normally; S3, read the transmission power and the two positive and reverse output voltages of the standing wave detection circuit, and calculate the standing wave ratio Vswr, the RF output signal power, and the return loss value respectively through the standing wave ratio and return loss calculation formulas; When the standing wave ratio Vswr is less than or equal to the standing wave ratio threshold Thr1, it works normally; when the standing wave ratio Vswr is between Thr1 and Thr2, the digital controlled attenuator is adjusted to reduce 1 adjustment step value; when the standing wave ratio Vswr is greater than Thr2, the gallium arsenide power amplifier tube, the three-stage gallium nitride power amplifier tube, and the final-stage gallium nitride power amplifier tube are immediately turned off; S4, read the RF small signal input signal power, calculate the transmission link gain, and obtain the transmission link efficiency; S5. Record and report the temperature sensor value, standing wave ratio, input signal power, output signal power, power amplifier switch state, transmission link efficiency, and transmission link gain obtained in the current detection cycle through the serial port, and estimate how many detection cycle transmission link state values ​​can meet the configuration parameter requirements.

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