Device for improving sensitivity of 6-18 GHz frequency division measurement and implementation method

Abstract

The application discloses a device for improving 6GHz-18GHz frequency division measurement sensitivity and an implementation method thereof. The device comprises a front-stage pretreatment link, a frequency band coarse division identification link, a frequency band gating frequency division measurement link and a down-conversion detection link connected in sequence. The front-stage pretreatment link is used for filtering out 6GHz-18GHz out-of-band interference and is provided with two output ends. One output end is connected to the frequency band coarse division identification link, and the other output end is connected to the down-conversion detection link. The frequency band coarse division identification link is used for frequency division identification of the pretreated signal. The frequency band gating frequency division measurement link is used for frequency selection feedback. The down-conversion detection link is used for completing down-conversion detection of 6GHz-18GHz radio frequency signals. The original 6GHz-18GHz wideband pass frequency band is divided into three sub-frequency bands of 6GHz-10GHz, 10GHz-14GHz and 14GHz-18GHz, the passband bandwidth is effectively narrowed, the sampling bandwidth is reduced, the out-of-band noise influence of the frequency selection passband is reduced, the frequency division measurement sensitivity is improved by more than 4dB, and the system fast response capability is maintained.

Description

Technical Field

[0001] This invention belongs to the field of microwave circuit technology, specifically, it relates to a device and method for improving the sensitivity of frequency division measurement in the 6GHz~18GHz range. Background Technology

[0002] The 6GHz–18GHz frequency band includes important radio frequency bands such as the C-band and X-band, and is widely used in radar signal reconnaissance, electromagnetic spectrum monitoring, and electronic warfare. With the rapid development of modern wireless communication and radar technology, the electromagnetic environment in this band is becoming increasingly complex. Signals in this band are characterized by dense spectrum, large instantaneous bandwidth, complex modulation types, coexistence of strong and weak signals, and various types of external signal interference. This places higher demands on the full-frequency coverage capability, receiving sensitivity, linear dynamic range, noise characteristics, and interference performance of radio frequency receiving systems.

[0003] Current 6GHz-18GHz RF receiving solutions mostly employ a segmented receiving framework, achieving frequency band coverage through multi-channel switching. This results in complex hardware link structures, low system integration, and low receiving efficiency, requiring repeated channel switching and scanning to ultimately lock onto the target frequency signal. Alternatively, there is a broadband RF receiving method that does not segment the 6GHz-18GHz frequency range and directly locks onto the target frequency through frequency division measurement. This solution offers fast response capabilities, but because the passband covers the entire 6GHz-18GHz band, the wide bandwidth leads to low final frequency division measurement sensitivity, failing to meet high sensitivity requirements. System sensitivity is determined by the system noise figure, sampling bandwidth, and minimum sampling signal-to-noise ratio (SNR). When the noise figure and minimum SNR are fixed, improving sensitivity can only be achieved by reducing the sampling bandwidth. This invention provides a device and method for improving the sensitivity of 6GHz-18GHz frequency division measurement, which achieves full-band reception from 6GHz to 18GHz while reducing the sampling bandwidth to improve system sensitivity.

[0004] When an uncertain signal enters the system within the 6GHz-18GHz frequency band, the existing segmented receiving framework determines its frequency band by switching and back-end frequency measurement / IF detection. This process is cumbersome and limited by the receiver's IF bandwidth and scanning speed, significantly increasing detection time and making it unsuitable for the rapidly changing battlefield. When an uncertain signal enters the system of this invention within the 6GHz-18GHz frequency band, the system responds instantaneously. It improves the frequency division and measurement sensitivity by 4dB compared to existing direct frequency division measurement in the 6GHz-18GHz range, ensuring instantaneous response while also detecting farther and weaker signals. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for improving the sensitivity of frequency division measurement in the 6GHz~18GHz range, mainly to solve the problem of low sensitivity of existing broadband receiver frequency measurement and improve the sensitivity of frequency division measurement.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A device for improving the sensitivity of frequency division measurement in the 6GHz~18GHz range includes a pre-processing link, a coarse band identification link, a band gating frequency division measurement link, and a down-conversion detection link connected in sequence.

[0008] The pre-processing link is used to filter out out-of-band interference from 6GHz to 18GHz and has two outputs. One output is connected to the frequency band coarse identification link, and the other output is connected to the down-conversion detection link.

[0009] The frequency band coarse division identification link is used to classify and identify the preprocessed signal.

[0010] The frequency band selection, frequency division, and frequency measurement link is used for frequency selection feedback;

[0011] The downconversion detection link is used to complete the downconversion detection of 6GHz~18GHz radio frequency signals. The frequency band coarse division identification link includes a second power divider that splits from one to three. The three outputs of the second power divider are respectively connected to a second filter, a third filter, and a fourth filter. The outputs of the second, third, and fourth filters are respectively connected to a first coupling device, a second coupling device, and a third coupling device. Each coupling device branches into a coupling branch and a direct branch. The coupling branches are respectively connected to a first amplitude measurement device, a second amplitude measurement device, and a third amplitude measurement device. The outputs of the three amplitude measurement devices are uniformly connected to an AD conversion device. The digital output of the AD conversion device is connected to a programmable logic controller (PLC). The direct branches of the three coupling devices are all connected to the frequency band selection and frequency division measurement link.

[0012] The second filter has a passband of 6GHz to 10GHz, the third filter has a passband of 10GHz to 14GHz, and the fourth filter has a passband of 14GHz to 18GHz.

[0013] Furthermore, in this invention, the pre-processing link includes a first filtering device, a first amplification device, an amplitude control device, a first power divider, and a second amplification device connected in sequence; wherein, the first power divider is a 1-to-2 power divider that divides the input signal into two paths, one path to the downconversion detection link, and the other path to the frequency band coarse identification link after passing through the second amplification device.

[0014] Furthermore, in this invention, the frequency band selection, frequency division, and frequency measurement link is sequentially provided with a single-pole triple-throw switch device for receiving control signals from a programmable logic control device, a frequency divider device for dividing the radio frequency signal by eight, a fifth filter device for filtering out frequency division spurious signals, and a frequency measurement device for outputting a precise frequency point; the frequency feedback terminal of the frequency measurement device is connected to the downconversion receiver link.

[0015] Furthermore, in this invention, the downconversion detection link is a mixer device, which receives the power division signal from the first power divider and the feedback signal from the frequency measurement device; the mixer device switches the corresponding local oscillator according to the target frequency fed back by the frequency measurement device to complete the downconversion detection of 6GHz~18GHz radio frequency signals.

[0016] Furthermore, in this invention, the programmable logic control device is used to acquire the three-channel power digital signals uploaded by the AD conversion device, identify the target radio frequency signal in the 6GHz~10GHz, 10GHz~14GHz, and 14GHz~18GHz segmented frequency bands, and output control signals to drive the switching device to select the corresponding segmented narrowband path, so that the frequency division device only performs frequency division and measurement on the narrowband signal after bandwidth compression, thereby reducing the system receiving bandwidth and out-of-band noise and improving the frequency division and measurement sensitivity.

[0017] Furthermore, in this invention, the amplitude control device is a digitally controlled attenuation unit, used to control the power amplitude of the input signal, improve the linear dynamic reception capability of the system, and ensure that the system can still output linearly when a large signal is input.

[0018] Based on the above-mentioned device, the present invention also provides a method for improving the sensitivity of frequency division measurement in the 6GHz~18GHz range, comprising the following steps:

[0019] S1: Signal preprocessing: The 6GHz~18GHz radio frequency signal is input to the first filter device for bandpass filtering. After filtering out out-of-band interference signals, it enters the first amplification device for low-noise amplification. The amplified signal enters the amplitude control device for power control. The signal after amplitude control enters the first power divider for power division. One of the power-divided signals enters the mixer device, and the other signal enters the second amplification device for secondary amplification.

[0020] S2: Signal power divider. The signal amplified by the second amplifier enters the second power divider. The second power divider divides the 6GHz~18GHz signal into three outputs, which are respectively entered into the second filter, the third filter and the fourth filter for segmented filtering.

[0021] S3: Segmented filtering. The second filter selectively filters signals in the 6GHz~10GHz frequency band, the third filter selectively filters signals in the 10GHz~14GHz frequency band, and the fourth filter selectively filters signals in the 14GHz~18GHz frequency band. When the target signal frequency falls within the passband of a certain filter, the signal power passes through the filter with almost no loss. When the target signal frequency is outside the passband of the filter, the signal power is significantly suppressed and absorbed.

[0022] S4: Coupling amplitude measurement. The three filtered signals are respectively fed into the corresponding coupling devices. The first coupling device couples the 6GHz~10GHz signal to the first amplitude measurement device for detection and amplitude measurement. The second coupling device couples the 10GHz~14GHz signal to the second amplitude measurement device for detection and amplitude measurement. The third coupling device couples the 14GHz~18GHz signal to the third amplitude measurement device for detection and amplitude measurement. The direct output terminals of the coupling devices output the signals to the switching devices respectively.

[0023] S5: AD conversion. The voltage signals output by the first amplitude measuring device, the second amplitude measuring device, and the third amplitude measuring device enter the AD conversion device. The AD conversion device converts the analog voltage signals into digital signals and uploads them to the programmable logic control device.

[0024] S6: Frequency band identification. After receiving the digital signal uploaded by the AD converter, the programmable logic controller analyzes the output results of the three amplitude measuring devices through a preset identification control algorithm. Based on the amplitude characteristics of each frequency band signal, it identifies the frequency band where the target signal is located and outputs a control signal to the switching device to select the signal path of the corresponding frequency band.

[0025] S7: Frequency division and measurement. The signal selected by the switching device enters the frequency divider for 8-fold frequency division. The divided signal enters the fifth filter to filter out stray signals and is finally sent to the frequency measurement device for accurate frequency measurement.

[0026] S8: Feedback mixing. After the frequency measurement device accurately measures the target frequency, it feeds the frequency information back to the mixing device. The mixing device switches to the corresponding local oscillator frequency according to the feedback frequency information, realizing fast downconversion reception from 6GHz to 18GHz.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) This invention divides the 6GHz~18GHz broadband passband into three sub-bands: 6GHz~10GHz, 10GHz~14GHz, and 14GHz~18GHz. It utilizes a coarse band identification link to detect the signal power of each sub-band in parallel. A programmable logic controller (PLC) quickly identifies the target signal's frequency band and selects the corresponding narrowband path, thus compressing the effective passband bandwidth of the frequency division measurement link from 12GHz to 4GHz. This significantly reduces the sampling bandwidth and out-of-band noise power. Under the condition that the system noise figure and minimum sampling signal-to-noise ratio remain unchanged, the reduction in sampling bandwidth directly translates into an increase in frequency division measurement sensitivity, enabling the system to detect target signals at greater distances and weaker signals, significantly enhancing the detection capabilities of radar signal reconnaissance and electromagnetic spectrum monitoring.

[0029] (2) This invention adopts a parallel power divider and segmented filtering architecture. The second power divider simultaneously distributes the preprocessed signal to three sub-band channels. The amplitude measurement device of each channel detects the signal power in real time and uploads it to the programmable logic controller (PLC) via the AD conversion device. The PLC uses a preset identification and control algorithm to complete the frequency band determination in one go and drive the switching device to select the corresponding path. The whole process does not require repeated channel switching and segmented scanning to lock the target frequency as in traditional segmented receiving schemes. It realizes instantaneous frequency band identification and rapid frequency measurement of any uncertain signal in the 6GHz~18GHz frequency band, which greatly shortens the system detection time. It is particularly suitable for electronic warfare and battlefield electromagnetic environment monitoring scenarios with strict real-time requirements.

[0030] (3) This invention introduces an amplitude control device composed of numerically controlled attenuation units into the pre-processing link. By cascading two stages of numerically controlled attenuators, precise power control with a minimum step of 0.5dB and a maximum attenuation of not less than 60dB is achieved, effectively expanding the linear dynamic reception capability of the system and ensuring that the system can still maintain linear output when strong signals are input, avoiding frequency measurement errors caused by nonlinear distortion. At the same time, the first filtering device in the pre-processing link adopts a cavity filter with an out-of-band rejection capability of not less than 40dBc, which can effectively filter out out-of-band interference signals; each sub-band filtering device also has an out-of-band rejection capability of not less than 40dBc, further suppressing interference from adjacent frequency band signals. In addition, the isolation of each branch of the switching device reaches more than 80dB, effectively preventing crosstalk of leakage signals to adjacent branches, so that the system can still maintain high reliability in frequency measurement performance in complex electromagnetic environments. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0033] like Figure 1 As shown, this invention discloses a device for improving the sensitivity of frequency division and measurement in the 6GHz~18GHz range. The overall structure of the device includes a pre-processing link, a coarse band identification link, a band gating frequency division and measurement link, and a down-conversion detection link connected in sequence. The pre-processing link is used to filter out out-of-band interference in the 6GHz~18GHz range and has two outputs. One output is connected to the coarse band identification link, and the other output is connected to the down-conversion detection link. The coarse band identification link is used to perform frequency division and identification on the pre-processed signal. The band gating frequency division and measurement link is used for frequency selection feedback. The down-conversion detection link is used to complete the down-conversion detection of the 6GHz~18GHz radio frequency signal.

[0034] In the signal input preprocessing stage, the 6GHz~18GHz RF signal first enters the first filtering device for bandpass filtering. The first filtering device is implemented using a cavity filter, with a passband frequency covering 6GHz~18GHz, insertion loss controlled within 1.5dB, in-band flatness better than ±0.5dB, and out-of-band rejection capability exceeding 40dBc. Compared to other types of filters, cavity filters have lower insertion loss, reducing the system noise figure. Simultaneously, their in-band flatness ensures the consistency of amplitude response within the intermediate frequency instantaneous bandwidth, while their high out-of-band rejection capability improves the system's anti-interference performance. The signal filtered by the first filtering device eliminates out-of-band interference components, providing a clean signal environment for subsequent low-noise amplification.

[0035] The signal filtered by the first filter enters the first amplification unit for low-noise amplification. The first amplification unit is implemented using a broadband low-noise amplifier, which has a noise figure as low as 1.5dB in the 6GHz~18GHz frequency band, provides a gain of 23dB, achieves a 1dB compression point of over 16dBm, and has a gain flatness controlled within ±0.5dB. It requires only a +5V single power supply and has a typical operating current of 65mA. As the first-stage low-noise amplification link in the system, the first amplification unit is the most important device for achieving the system's low-noise performance; its low-noise figure characteristics directly determine the sensitivity of the entire receiving system.

[0036] The signal amplified by the first amplifier enters the amplitude control unit for power amplitude control. The amplitude control unit employs a digitally controlled attenuation unit, consisting of a combination of HGC234D and HGC241L digitally controlled attenuators. The HGC234D achieves a dynamic attenuation range of 35dB in 5dB steps, while the HGC241L achieves a dynamic attenuation range of 31.5dB in 0.5dB steps. When cascaded, they achieve a minimum attenuation step of 0.5dB and a maximum dynamic attenuation range exceeding 60dB. The digitally controlled attenuation unit precisely adjusts the input signal power through digital control, expanding the system's linear dynamic reception capability and ensuring linear output even with large signal inputs, avoiding nonlinear distortion caused by excessively strong signals. When the input signal power is high, the programmable logic controller automatically controls the amplitude control unit to increase the attenuation by detecting the output level of the amplitude measuring device, preventing the subsequent amplifier from entering saturation. When the input signal power is low, the attenuation can be appropriately reduced or the system can be set to a direct-through state to maintain the system's signal-to-noise ratio.

[0037] The signal processed by the amplitude control device enters the first power divider for power division. The first power divider employs a wideband high-isolation power divider, specifically the HGC155H model, which has an insertion loss of no more than 0.9dB in the 6GHz~18GHz frequency band and an isolation of over 18dB between its power branches. The first power divider splits the input signal into two paths: one output goes to the mixer for down-conversion and conventional RF reception processing; the other output goes to the second amplifier for subsequent frequency division and measurement. The high isolation characteristic of the power divider ensures isolation between the two power branches, preventing back crosstalk from affecting system performance.

[0038] The signal entering the frequency measurement branch is amplified twice by the second amplification unit after passing through the first power divider. The second amplification unit also employs a low-noise amplification link, consisting of a low-noise amplifier, an equalizer, a temperature-compensated attenuator, and a filter. The low-noise amplifier provides the necessary system gain, and the equalizer achieves amplitude equalization within the 6GHz-18GHz frequency band, ensuring that the gain characteristics remain essentially consistent across the entire band and avoiding inconsistencies in sensitivity caused by uneven gain frequency response. The temperature-compensated attenuator compensates for gain variations in the amplifier at high and low temperatures. The amplifier gain increases at low temperatures and decreases at high temperatures; the temperature-compensated attenuator compensates for this gain difference, ensuring that the system's gain remains essentially consistent across a wide operating temperature range.

[0039] The signal amplified by the second amplification device enters the second power divider for secondary power division. The second power divider is a 1-to-3 power divider, using the IPD-06183 model, with an insertion loss not exceeding 0.5dB, an isolation of over 18dB between power divider ports, and high amplitude and phase consistency across all power branches. The second power divider divides the 6GHz~18GHz broadband RF signal into three outputs, which are then fed into three different frequency band filtering channels, providing the signal distribution basis for subsequent segmented filtering processing. This step is one of the core innovations of this invention; by power-dividing the full-band signal in parallel to three sub-band channels for processing, it avoids the cumbersome process of switching between frequency bands one by one, as required by traditional solutions.

[0040] The three outputs of the second power divider are respectively fed into the second, third, and fourth filtering devices for segmented filtering. The second filtering device is a bandpass filter operating in the 6GHz~10GHz frequency band, with a passband frequency range of 6GHz~10GHz, and has a suppression capability of no less than 40dBc for out-of-band signals in the DC to 5GHz and 11GHz~25GHz frequency bands. The third filtering device is a bandpass filter operating in the 10GHz~14GHz frequency band, with a passband frequency range of 10GHz~14GHz, and has a suppression capability of no less than 40dBc for out-of-band signals in the DC to 9GHz and 15GHz~25GHz frequency bands. The fourth filtering device is a bandpass filter operating in the 14GHz~18GHz frequency band, with a passband frequency range of 14GHz~18GHz, and has a suppression capability of no less than 40dBc for out-of-band signals in the DC to 13GHz and 19GHz~40GHz frequency bands. The passband frequencies of the three filters are connected to fully cover the entire 6GHz~18GHz frequency band, achieving the technical effect of splitting the original wideband into three sub-bands. When the target signal frequency falls within the passband range of a certain filter, the signal power can pass through the filter with almost no loss; when the target signal frequency is outside the passband range of the filter, the signal power is significantly suppressed and absorbed, thereby effectively narrowing the effective bandwidth of each branch.

[0041] The outputs of the second, third, and fourth filtering devices are respectively fed into the corresponding first, second, and third coupling devices. The coupling devices are implemented using ceramic resistive couplers, fabricated using a thin-film circuit method on a ceramic substrate with a dielectric constant of 9.8. The first coupling device couples a 6GHz~10GHz frequency band signal to the first amplitude measurement device for power measurement, with a coupling end loss of approximately 15dB and a pass-through end loss of approximately 1.5dB. The second coupling device couples a 10GHz~14GHz frequency band signal to the second amplitude measurement device for power measurement. The third coupling device couples a 14GHz~18GHz frequency band signal to the third amplitude measurement device for power measurement. The pass-through end of each coupling device outputs a signal corresponding to its frequency band, which is then fed into the switching device. The design of the coupling devices allows for the extraction of a portion of the signal power for power detection without affecting the pass-through signal transmission characteristics, enabling rapid determination of the presence and power amplitude of signals in each frequency band.

[0042] The first, second, and third amplitude measurement devices are all implemented using amplified logarithmic detection links, receiving signals coupled from the outputs of the first, second, and third coupling devices, respectively, for power measurement. The amplitude measurement devices utilize ARW254 logarithmic amplifiers, capable of covering an input frequency range of 1GHz to 23GHz, achieving a detection amplitude measurement function with a dynamic range of 54dB, and controlling the logarithmic detection error within ±1dB. The amplitude measurement devices cover the RF input dynamic range by adjusting the dynamic range of the amplified logarithmic detection, ensuring complete power measurement functionality within the designed RF input dynamic range. When the target signal exists in the corresponding frequency band, the amplitude measurement device outputs a voltage signal corresponding to the signal power; when the target signal does not exist in the corresponding frequency band, the amplitude measurement device outputs a low-level voltage signal or a voltage signal close to the noise floor.

[0043] The output voltage signals from the first, second, and third amplitude measuring devices are respectively fed into an AD converter for analog-to-digital conversion. The AD converter uses the AD9268 high-speed ADC chip, capable of dual-channel analog-to-digital conversion with 16-bit resolution and a 125MSPS sampling rate. The AD converter quickly converts the analog voltage signals output from the three amplitude measuring devices into digital signals and uploads them to the programmable logic controller (PLC) for processing via a parallel data interface. The use of a high-speed ADC ensures real-time signal sampling, keeping pace with the changing signal frequencies.

[0044] The programmable logic controller (PLC) acts as the main control and processing unit of the system. After receiving the three channels of digital signals from the AD converter, it analyzes and processes the data using a preset recognition and control algorithm. The PLC uses an EG4A20NG88I7 device to implement system logic processing and switching control functions. Its recognition algorithm works as follows: Assuming the external input signal frequency is 8GHz, after passing through the second power divider, the signal enters the second, third, and fourth filters. The passband frequency of the second filter covers 8GHz, so the 8GHz signal passes through it almost without loss into the subsequent link. However, when passing through the third and fourth filters, the 8GHz frequency is outside its channel frequency range, and the signal power is significantly suppressed and absorbed. At this point, the first amplitude measuring device detects a high signal level, while the second and third amplitude measuring devices detect levels close to the noise floor. By comparing the output level values ​​of the three amplitude measuring devices, the PLC can determine that the target signal is within the 6GHz~10GHz frequency band. When the target signal frequency is at the intersection of the frequency bands of the second, third, and fourth filters, for example, when the signal frequency is 12GHz, the signal can pass through the third filter and part of the transition band between the second and fourth filters at the same time. The programmable logic controller determines which frequency range the target signal belongs to by means of multi-point sampling and amplitude difference analysis.

[0045] After identifying the frequency band of the target signal, the programmable logic controller (PLC) outputs a corresponding control signal to the switching device. The switching device uses a single-pole triple-throw switch, specifically an HGC120 single-pole quadruple-throw switch, with the extra path used as a backup. To ensure isolation between branches, a single-pole single-throw switch is connected in series at each branch of the single-pole quadruple-throw switch, achieving an isolation of over 80dB between branches, effectively isolating leakage signals from interfering with other branches. Based on the control signal from the PLC, the switching device selects the signal path for the corresponding frequency band and outputs the signal of that band to the frequency divider.

[0046] The frequency divider is a wideband 8-divider, using the SID027 programmable divider, capable of covering an input frequency range of 21GHz. It enables 2-bit control for 1 / 2 / 4 / 8-divide outputs and boasts the industry's lowest single-sideband phase noise. The divider performs an 8-divide process on the input 6GHz~18GHz frequency signal, outputting a signal with a frequency range of 0.75GHz~2.25GHz. By converting high-frequency signals into low-frequency signals for frequency measurement, the frequency division significantly reduces the implementation difficulty of the frequency measurement circuit, and the divided signal frequency is easier to process in subsequent digital signal processing.

[0047] The signal output from the frequency divider enters the fifth filter for filtering. This fifth filter is a low-pass filter, used to remove spurious signals and harmonic components generated during the frequency division process, ensuring the purity of the signal entering the frequency measurement device. The cutoff frequency of the low-pass filter is set to approximately 2.5 GHz, effectively filtering out multiple harmonic components generated by the 8-way frequency division.

[0048] The purified signal, filtered by the fifth filter, enters the frequency measurement device for precise frequency measurement. The frequency measurement device accurately measures the frequency value of the target signal and feeds back the measured frequency information to the mixer. Based on the frequency information fed back by the frequency measurement device, the mixer quickly switches to the corresponding local oscillator frequency, achieving rapid down-conversion reception of signals from 6GHz to 18GHz. This step completes the closed-loop control of the entire system, enabling the system to automatically adjust the local oscillator according to the detected target frequency, achieving precise down-conversion processing.

[0049] The workflow of this invention can be summarized into the following eight main steps:

[0050] S1: Signal preprocessing. The 6GHz~18GHz radio frequency signal is input to the first filter device for bandpass filtering. After filtering out out-of-band interference signals, it enters the first amplification device for low-noise amplification. The amplified signal enters the amplitude control device for power control. The signal after amplitude control enters the first power divider for power division. One of the power-divided signals enters the mixer device, and the other signal enters the second amplification device for secondary amplification.

[0051] S2: Signal power divider. The signal amplified by the second amplifier enters the second power divider. The second power divider divides the 6GHz~18GHz signal into three outputs, which are respectively fed into the second filter, the third filter, and the fourth filter for segmented filtering.

[0052] S3: Segmented filtering. The second filter selectively filters signals in the 6GHz~10GHz frequency band, the third filter selectively filters signals in the 10GHz~14GHz frequency band, and the fourth filter selectively filters signals in the 14GHz~18GHz frequency band. When the target signal frequency falls within the passband of a certain filter, the signal power passes through the filter with almost no loss. When the target signal frequency is outside the passband of the filter, the signal power is significantly suppressed and absorbed.

[0053] S4: Coupling amplitude measurement. The three filtered signals are respectively fed into the first coupling device, the second coupling device, and the third coupling device. The first coupling device couples the 6GHz~10GHz signal to the first amplitude measurement device for detection and amplitude measurement. The second coupling device couples the 10GHz~14GHz signal to the second amplitude measurement device for detection and amplitude measurement. The third coupling device couples the 14GHz~18GHz signal to the third amplitude measurement device for detection and amplitude measurement. The direct output terminals of the coupling devices output the signals to the switching devices respectively.

[0054] S5: AD conversion. The voltage signals output by the first amplitude measuring device, the second amplitude measuring device, and the third amplitude measuring device enter the AD conversion device. The AD conversion device converts the analog voltage signals into digital signals and uploads them to the programmable logic control device.

[0055] S6: Frequency band identification. After receiving the digital signal uploaded by the AD converter, the programmable logic controller analyzes the output results of the three amplitude measuring devices through a preset identification control algorithm. Based on the amplitude characteristics of each frequency band signal, it identifies the frequency band where the target signal is located and outputs a control signal to the switching device to select the signal path of the corresponding frequency band.

[0056] S7: Frequency division and measurement. The signal selected by the switching device enters the frequency divider for 8-fold frequency division. The divided signal enters the fifth filter to filter out stray signals and is finally sent to the frequency measurement device for accurate frequency measurement.

[0057] S8: Feedback mixing. After the frequency measurement device accurately measures the target frequency, it feeds the frequency information back to the mixing device. The mixing device quickly switches to the corresponding local oscillator frequency according to the feedback frequency information, realizing fast downconversion detection from 6GHz to 18GHz.

[0058] In practical applications, this invention can be applied to radar signal reconnaissance systems, electromagnetic spectrum monitoring systems, and electronic countermeasures equipment. When an unknown signal enters the 6GHz~18GHz frequency band, the system of this invention can complete the frequency band identification and accurate frequency measurement of the target signal in a very short time, without the need for repeated channel switching and scanning as required by traditional segmented receiving schemes, thus greatly shortening the system detection time. Simultaneously, by dividing the original 6GHz~18GHz wideband into three 4GHz sub-bands for parallel processing, the noise bandwidth entering the subsequent frequency division and measurement link is effectively reduced. According to the relationship between system sensitivity and sampling bandwidth, with a fixed system noise figure and minimum sampling signal-to-noise ratio, the reduction in sampling bandwidth directly leads to an improvement in system sensitivity. This invention can achieve a technical effect of improving frequency division and measurement sensitivity by at least 4dB.

[0059] This invention also has good scalability. When the system requires higher sensitivity, the 6GHz~18GHz frequency band can be divided into more sub-bands by increasing the number of power dividers, for example, into four or more bands. The bandwidth of each sub-band is further narrowed, thereby obtaining higher frequency division measurement sensitivity. This expansion method does not require major modifications to the system architecture; it can be achieved simply by adding the corresponding number of power dividers, filtering devices, and amplitude measurement channels.

[0060] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A device for improving the sensitivity of frequency division measurement from 6GHz to 18GHz, characterized in that, This includes a pre-processing link, a coarse frequency band identification link, a frequency band gating and frequency division measurement link, and a down-conversion detection link connected in sequence. The pre-processing link is used to filter out out-of-band interference from 6GHz to 18GHz and has two outputs. One output is connected to the frequency band coarse identification link, and the other output is connected to the down-conversion detection link. The frequency band coarse division identification link is used to classify and identify the preprocessed signal. The frequency band selection, frequency division, and frequency measurement link is used for frequency selection feedback; The downconversion detection link is used to complete the downconversion detection of 6GHz~18GHz radio frequency signals; wherein, the frequency band coarse division identification link includes a second power divider that splits from one to three, and a second filter, a third filter, and a fourth filter that are respectively connected to the three output terminals of the second power divider. The output terminals of the second filter, the third filter, and the fourth filter are respectively connected to a first coupling device, a second coupling device, and a third coupling device. Each set of coupling devices is divided into a coupling branch and a direct branch. The coupling branch is connected to the first amplitude measurement device, the second amplitude measurement device, and the third amplitude measurement device, respectively. The output of the three sets of amplitude measurement devices is connected to the AD conversion device. The digital output of the AD conversion device is connected to the programmable logic control device. The direct branches of the three sets of coupling devices are connected to the frequency band selection and frequency division measurement link. The second filter has a passband of 6GHz to 10GHz, the third filter has a passband of 10GHz to 14GHz, and the fourth filter has a passband of 14GHz to 18GHz.

2. The device for improving the sensitivity of frequency division measurement from 6GHz to 18GHz according to claim 1, characterized in that, The pre-processing link includes a first filter device, a first amplification device, an amplitude control device, a first power divider device, and a second amplification device connected in sequence; wherein, the first power divider device is a 1-to-2 power divider that divides the input signal into two paths, one path goes to the downconversion detection link, and the other path goes to the frequency band coarse identification link after passing through the second amplification device.

3. The device for improving the sensitivity of frequency division measurement from 6GHz to 18GHz according to claim 2, characterized in that, The frequency band selection, frequency division, and frequency measurement link is sequentially equipped with a single-pole triple-throw switch for receiving control signals from a programmable logic controller, a frequency divider for dividing the radio frequency signal by eight, a fifth filter for filtering out frequency division spurious signals, and a frequency measurement device for outputting a precise frequency point; the frequency feedback terminal of the frequency measurement device is connected to the downconversion receiver link.

4. The device for improving the sensitivity of 6GHz~18GHz frequency division measurement according to claim 3, characterized in that, The downconversion detection link is a mixer device. The mixer device receives the power division signal from the first power divider and the feedback signal from the frequency measurement device. The mixer device switches the corresponding local oscillator according to the target frequency fed back by the frequency measurement device to complete the downconversion detection of 6GHz~18GHz radio frequency signals.

5. The device for improving the sensitivity of frequency division measurement from 6GHz to 18GHz according to claim 4, characterized in that, The programmable logic controller is used to acquire the three-channel power digital signals uploaded by the AD conversion device, identify the target radio frequency signal in the 6GHz~10GHz, 10GHz~14GHz, and 14GHz~18GHz segmented frequency bands, and output control signals to drive the switching device to select the corresponding segmented narrowband path, so that the frequency division device only divides and measures the narrowband signal after the bandwidth is compressed, thereby reducing the system receiving bandwidth and out-of-band noise and improving the frequency division and measurement sensitivity.

6. The device for improving the sensitivity of frequency division measurement from 6GHz to 18GHz according to claim 5, characterized in that, The amplitude control device is a digitally controlled attenuation unit, which is used to control the power amplitude of the input signal, improve the linear dynamic reception capability of the system, and ensure that the system can still output linearly when a large signal is input.

7. A method for improving the sensitivity of frequency division measurement in the 6GHz~18GHz range, characterized in that, The apparatus described in claim 6 includes the following steps: S1: Signal preprocessing: The 6GHz~18GHz radio frequency signal is input to the first filter device for bandpass filtering. After filtering out out-of-band interference signals, it enters the first amplification device for low-noise amplification. The amplified signal enters the amplitude control device for power control. The signal after amplitude control enters the first power divider for power division. One of the power-divided signals enters the mixer device, and the other signal enters the second amplification device for secondary amplification. S2: Signal power divider. The signal amplified by the second amplifier enters the second power divider. The second power divider divides the 6GHz~18GHz signal into three outputs, which are respectively entered into the second filter, the third filter and the fourth filter for segmented filtering. S3: Segmented filtering. The second filter selectively filters signals in the 6GHz~10GHz frequency band, the third filter selectively filters signals in the 10GHz~14GHz frequency band, and the fourth filter selectively filters signals in the 14GHz~18GHz frequency band. When the target signal frequency falls within the passband of a certain filter, the signal power passes through the filter with almost no loss. When the target signal frequency is outside the passband of the filter, the signal power is significantly suppressed and absorbed. S4: Coupling amplitude measurement. The three filtered signals are respectively fed into the corresponding coupling devices. The first coupling device couples the 6GHz~10GHz signal to the first amplitude measurement device for detection and amplitude measurement. The second coupling device couples the 10GHz~14GHz signal to the second amplitude measurement device for detection and amplitude measurement. The third coupling device couples the 14GHz~18GHz signal to the third amplitude measurement device for detection and amplitude measurement. The direct output terminals of the coupling devices output the signals to the switching devices respectively. S5: AD conversion. The voltage signals output by the first amplitude measuring device, the second amplitude measuring device, and the third amplitude measuring device enter the AD conversion device. The AD conversion device converts the analog voltage signals into digital signals and uploads them to the programmable logic control device. S6: Frequency band identification. After receiving the digital signal uploaded by the AD converter, the programmable logic controller analyzes the output results of the three amplitude measuring devices through a preset identification control algorithm. Based on the amplitude characteristics of each frequency band signal, it identifies the frequency band where the target signal is located and outputs a control signal to the switching device to select the signal path of the corresponding frequency band. S7: Frequency division and measurement. The signal selected by the switching device enters the frequency divider for 8-fold frequency division. The divided signal enters the fifth filter to filter out stray signals and is finally sent to the frequency measurement device for accurate frequency measurement. S8: Feedback mixing. After the frequency measurement device accurately measures the target frequency, it feeds the frequency information back to the mixing device. The mixing device switches to the corresponding local oscillator frequency according to the feedback frequency information, realizing fast downconversion reception from 6GHz to 18GHz.

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