CN110988473B - Broadband burst signal spectrum analyzer and broadband burst signal analysis method - Google Patents
Broadband burst signal spectrum analyzer and broadband burst signal analysis method Download PDFInfo
- Publication number
- CN110988473B CN110988473B CN201911169851.8A CN201911169851A CN110988473B CN 110988473 B CN110988473 B CN 110988473B CN 201911169851 A CN201911169851 A CN 201911169851A CN 110988473 B CN110988473 B CN 110988473B
- Authority
- CN
- China
- Prior art keywords
- frequency
- spectrum
- signal
- unit
- time
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/16—Spectrum analysis; Fourier analysis
- G01R23/165—Spectrum analysis; Fourier analysis using filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mathematical Physics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Frequencies, Analyzing Spectra (AREA)
Abstract
The invention discloses a broadband burst signal spectrum analyzer and a broadband burst signal analysis method, and belongs to the technical field of electronic measurement. The signal analysis capability of the technical scheme of the invention is stronger, and the execution bandwidth is larger than the acquisition and analysis bandwidth of an instrument; the technical scheme of the invention has high measurement efficiency, and for burst signals with unknown signal occurrence time, frequency and duration, the detection interception capability of the technical scheme of the invention on the signals is superior to that of the traditional technical scheme; according to the technical scheme, the tuning local oscillator can perform tuning frequency stepping according to the change characteristics of the input signal, and interested signal spectrum data can be obtained quickly.
Description
Technical Field
The invention belongs to the technical field of electronic measurement, and particularly relates to a broadband burst signal spectrum analyzer and a broadband burst signal analysis method.
Background
With the development of digital technology, various broadband signals and burst signals emerge endlessly. The ability to quickly search for or measure these bursts in the ultra-wide frequency range represents an important indicator of the state of the art of radio receiving equipment. Searching or measuring radio signals over a wide frequency band is one of important contents of radio measurement or monitoring work. The superheterodyne tuning receiving and processing equipment can perform tuning receiving in an extremely wide frequency range, has the advantages of wide frequency coverage, large dynamic range, high sensitivity, high cost performance and the like, and is widely applied. In order to improve the interception capability of the superheterodyne tuning reception and processing system for the burst signal, the tuning speed and the processing speed of the system are continuously sought after by the superheterodyne reception system.
The first commonly used solution is a high-speed continuous swept frequency spectrum analysis process, such as a swept-frequency microwave spectrum analyzer. The technical scheme can quickly carry out frequency spectrum measurement in a wide frequency range, and the scanning speed of the technical scheme mainly depends on the local oscillator tuning rate and the response speed of a medium-frequency resolution bandwidth filter. Taking a frequency span of 50GHz and a resolution bandwidth of 3MHz as an example, the scanning time of a swept spectrum analyzer is about 100ms, but for burst signals in an electromagnetic space, the signal power is generally low, and in order to improve the sensitivity of spectrum measurement, the resolution bandwidth of spectrum measurement needs to be reduced. The spectrum measurement time is inversely proportional to the square of the resolution bandwidth, which is a frequency span of 100MHz, a resolution bandwidth of 10kHz, and a sweep spectrum analyzer sweep time of about 2.5 seconds. Even if the system and method for measuring the frequency spectrum of the radio frequency signal by high-speed frequency sweep based on the digital local oscillator (201210580327.1) is adopted, the limitation of the response time of the intermediate frequency filter cannot be eliminated. Therefore, for a wide frequency range and a high frequency resolution, the detection and interception capabilities of the swept-frequency spectrum analysis scheme on the burst signals are poor.
In order to increase the scanning speed under a small resolution bandwidth, the second technical scheme is a scheme of FFT spectrum analysis, which is most typically represented by an intermediate frequency digital spectrum analyzer, and the principle is shown in fig. 1.
The input signal is mixed with a local oscillator signal with tunable frequency to become an intermediate frequency signal, the intermediate frequency signal is filtered by a filter to remove an image frequency signal, the ADC digitizes and preprocesses the filtered intermediate frequency signal, the preprocessed digital signal is subjected to real-time frequency spectrum calculation, the calculated frequency spectrum data forms a spectrogram which expresses the change of the frequency spectrum of the input signal along with time and is beneficial to analyzing broadband burst signals. The scanning controller is used for controlling the tuning of the local oscillation signal.
In the second technical scheme, the frequency span of the analysis is (F2-F1), F1 represents the starting frequency of the analysis, F2 represents the ending frequency of the analysis as F2, and | F2-F1<BIF，BIFIs the maximum analysis bandwidth. Controlling local oscillator signal tuning by a scan controllerThe output frequency can be generated by real-time Fourier transform spectrum of any frequency span from F1 to F2 in the whole tuning frequency range of the instrument.
But when | F2-F1>BIFAnd then the local oscillator is tuned to the next frequency point in a stepping manner through the scanning controller, and the FFT frequency spectrum processing is carried out again, and the analogy is carried out until the frequency spectrum information of all frequency spans is obtained. As shown in FIG. 2, assume that the analyzed frequency span | F2-F1| is 6 times BIFAs shown in fig. 2A, the local oscillator frequency may be tuned to FLO1 first, and then received and analyzed from frequency F1 to frequency (F1+ B)IF) After the analysis is completed, the local oscillation frequency is tuned to FLO2 by the scanning controller, and the slave frequency (F1+ B) is received and analyzed at the momentIF) To frequency (F1+ 2B)IF) After the signals are analyzed, the local oscillation frequency is tuned to FLO3 through the scanning controller, and the like until all frequencies are finished (F1+ 5B)IF) Signal analysis processing task to frequency F2. Thus, the acquisition of the spectrum data with the frequency span of (F2-F1) is completed once, and then the cost of T is further spentCTime-through-scan controller tuning local oscillator frequency to FLOAnd 1, repeating the steps. Shown in FIG. 2C, TCThe parameter setting time, also referred to as the hardware and software recovery time, represents the time between two frequency measurements. The second technical solution has a considerable advantage over the first technical solution in the case of a wide frequency range and a high frequency resolution in the spectrum measurement speed. It can be seen that in the second technical solution, the spectrum measurement time ST is N × TPWhere N denotes the number of steps, TPIndicating the dwell time for each step.
TPGenerally, the method includes a system rise time, an acquisition time, and an FFT spectrum calculation time, in the technical scheme shown in fig. 2, the FFT spectrum calculation may be processed in real time, that is, the FFT spectrum calculation time is less than or equal to the acquisition time, the acquisition and the FFT spectrum calculation may be processed in parallel in a pipeline manner, and T is TpThe time mainly includes the system rise time and the acquisition time.
Fig. 2 assumes the frequency switching time T of the local oscillator step tuningFZero, T in the actual projectFAnd cannot be zero. FIG. 3 shows TFTime relation graph with time not being zero. It can be seen that in the second solution, the frequency measurement time ST is N × TP+(N-1)*TFWhere N denotes the number of steps, TPRepresenting the dwell time of each step, consisting essentially of the system rise time and acquisition time, TFIndicating the frequency switching time of the step tuning.
In order to further improve the interception capability of the burst signal, for the second technical solution, the improved technical solution mainly includes: one is to try to increase the frequency width of each step. I.e. increase the intermediate frequency bandwidth BIFReducing the stepping times N; secondly, the processing speed of FFT frequency spectrum of each step is accelerated, and the staying time T of each step is reduced as much as possibleP(ii) a Thirdly, the frequency switching time T of each step tuning is reduced as much as possibleF. Fourthly, the tuning parameter setting time T between two measurements is reduced as much as possibleC。
In the second technical scheme, increasing the analysis bandwidth inevitably results in improving the intermediate frequency acquisition speed, and is limited by the current ADC device, the higher the ADC acquisition speed is, the less the acquisition number is, the lower the signal-to-noise ratio and the dynamic range are, and the interception capability of weak burst signals is influenced; medium frequency bandwidth BIFIncrease, in order to reach the required frequency resolution, inevitably lead to the increase of the acquisition point number and the FFT point number, the FFT point number is increased by N times, the FFT operation amount is increased by Nlog2N times, so the processing speed will also be affected, possibly resulting in TPThe time is increased, and in addition, the number of FFT points is limited by the maximum number of FFT points. Meanwhile, in the second technical scheme, the frequency switching time T is reducedFOr TCThe adopted technical means generally causes that the hardware design difficulty is greatly increased, the cost is increased, or the performances of the receiver such as phase noise and the like are reduced. In addition, under the current technical conditions, the Tf time is often comparatively large, and the influence on the speed cannot be ignored. Therefore, wideband burst signaling is measured over a frequency span greater than the analysis bandwidthWhen the number is large, the analysis capability of the second technical scheme is greatly reduced.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a broadband burst signal spectrum analyzer and a broadband burst signal analysis method, which are reasonable in design, overcome the defects of the prior art and have good effects.
In order to achieve the purpose, the invention adopts the following technical scheme:
a broadband burst signal spectrum analyzer comprises a superheterodyne frequency conversion receiving unit, a local oscillation unit, a filter, an ADC acquisition and preprocessing unit, a signal characteristic extraction unit, a scanning controller, a spectrum processing unit and a display unit;
the superheterodyne frequency conversion receiving unit is configured to mix an input signal and a local oscillator signal with tunable frequency into an intermediate frequency signal;
and the local oscillation unit is configured to be used for providing a local oscillation signal required by the superheterodyne frequency conversion receiving unit.
A filter configured to filter out an image signal;
an ADC acquisition and pre-processing unit configured for acquiring and pre-processing the intermediate frequency signal, the pre-processing including digital frequency conversion and decimation filtering processing for achieving a required analysis bandwidth and frequency resolution;
a signal feature extraction unit configured to extract basic features of an appearance time, a duration and a disappearance time of the input signal to be detected, a repetition period, or a frequency switching time of the input signal to be detected according to the signal instantaneous frequency feature;
the scanning controller is configured to control frequency switching of a tuned local oscillator and residence time of a certain tuned frequency point according to the signal features extracted by the signal feature extraction unit, specifically, the time features of appearance, disappearance or frequency switching of a detected signal can be used for controlling the switching of the local oscillator, and the time features of duration and repetition period of the detected signal can be used for controlling the residence time of the local oscillator;
a spectrum processing unit configured to perform a windowed real-time FFT transform process and a spectrum statistical process on a plurality of frames of FFT spectrum data or a maximum hold process, an average process, and a minimum hold process on a plurality of frames of FFT spectrum data; constructing spectrum tracks of all measured frequency spans from spectrum tracks of different frequency intervals measured for multiple times, specifically constructing a statistical spectrum track of all measured frequency spans from a statistical spectrum track of each step measurement, or constructing a maximum retention spectrum track of all measured frequency spans from a maximum retention spectrum track of each step measurement, or constructing an average processing spectrum track of all measured frequency spans from an average processing spectrum track of each step measurement, or constructing a minimum retention spectrum track of all measured frequency spans from a minimum retention spectrum track of each step measurement;
a display unit configured to simultaneously display the statistical spectrum locus, the maximum-maintained spectrum locus, the average spectrum locus or the minimum-maintained spectrum locus in a multi-window form;
the superheterodyne frequency conversion receiving unit mixes an input signal and a local oscillation signal provided by the local oscillation unit into an intermediate frequency signal, the intermediate frequency signal enters an ADC (analog to digital converter) acquisition and preprocessing unit after being filtered by a filter, the ADC acquisition and preprocessing unit acquires and preprocesses the intermediate frequency signal, the preprocessing comprises digital frequency conversion and extraction filtering processing for realizing required analysis bandwidth and frequency resolution, baseband IQ signal data formed after preprocessing enters a frequency spectrum processing unit, and the baseband IQ signal data is displayed on a display unit after being processed by the frequency spectrum processing unit; the scanning controller controls the local oscillation unit to output expected local oscillation signals according to the characteristic information output by the signal characteristic extraction unit.
Preferably, the superheterodyne frequency conversion receiving unit is a one-stage or multi-stage frequency conversion unit.
Preferably, the filter is a cascade of a plurality of intermediate frequency filters, and the intermediate frequency filters include a filter of each stage of the intermediate frequency chain and an anti-aliasing filter of the ADC front end, and the bandwidth of each stage of the intermediate frequency filter is different, and the bandwidth of the intermediate frequency filter closer to the radio frequency input end is larger.
Preferably, the input signal is a signal of an arbitrary stage intermediate frequency link or a radio frequency input signal.
In addition, the present invention also provides a wideband burst signal analysis method, which uses the wideband burst signal spectrum analyzer as described above, and includes the following steps:
step 1: determining a starting frequency F1 and a terminating frequency F2 required for analyzing the broadband burst signal, wherein the frequency span is larger than the analysis bandwidth RTBW of a spectrum analyzer, and the frequency span is F2-F1, F2-F1> RTBW;
step 2: selecting a frequency resolution used for analyzing the broadband burst signal, and determining a STEP bandwidth STEP _ BW of each analysis according to the resolution and the analysis bandwidth of a spectrum analyzer, wherein the STEP _ BW is less than or equal to RTBW;
and step 3: the scanning controller sets the output of the local oscillation unit to a first tuning frequency point, and a first section of frequency interval corresponding to frequency spectrum data from F1 to F2 can be obtained through the first tuning frequency point, wherein the starting frequency of the frequency interval is F1, and the ending frequency of the frequency interval is F1+ STEP _ BW;
and 4, step 4: the signal characteristic extraction unit extracts the signal residence time characteristic and transmits the time parameter to the scanning controller, the scanning controller determines the residence time of a first tuning frequency point of a local oscillator of the superheterodyne frequency conversion receiving unit, and the frequency spectrum processing unit performs frequency spectrum processing on output data of the ADC acquisition and preprocessing unit within the residence time to obtain frequency spectrum data of a first section of frequency interval;
and 5: the scanning controller controls the output of the local oscillation unit to be switched from a first tuning frequency point to a second tuning frequency point, and a second frequency interval corresponding to frequency spectrum data from F1 to F2 can be obtained through the second tuning frequency point, wherein the starting frequency of the second frequency interval is F1+ STEP _ BW, and the ending frequency of the second frequency interval is F1+2 STEP _ BW;
step 6: the scanning controller controls the residence time of the second tuning frequency point according to the signal characteristics output by the signal characteristic extraction unit, and the frequency spectrum processing unit performs frequency spectrum processing on the output data of the ADC acquisition and preprocessing unit within the residence time to obtain frequency spectrum data of a second section of frequency interval;
and 7: repeating the steps 3-6 until the measurement of all tuning frequency points is completed and all frequency intervals with the frequency span of F2-F1 are covered;
and 8: and the spectrum processing unit constructs the spectrum data corresponding to all the tuning frequency points into all the spectrum tracks with the frequency span of F2-F1.
Preferably, the spectrum processing in step 4 and step 6 includes: obtaining a statistical spectrum track of a corresponding frequency interval in residence time, or obtaining a maximum retention spectrum track of the corresponding frequency interval in residence time, or obtaining a minimum retention spectrum track of the corresponding frequency interval in residence time, or obtaining an average spectrum track of the corresponding frequency interval in residence time, or simultaneously obtaining a plurality of spectrum tracks.
The invention has the following beneficial technical effects:
by adopting the technical scheme of the invention, the stay time of each step can be set to stay for at least one signal period, the maximum retention spectrum data measurement can be executed in the stay time, and after the execution of N steps is finished, the complete signal spectrum can be constructed by using the maximum retention spectrum data of each step.
In addition, in the case of the present invention, it is assumed that M measurements are performed during the dwell time of each step, and that the time T0 taken to perform M measurements in the entire frequency span is M × N × TP+(N-1)*TF(ii) a Obviously, as long as N is greater than 1 and M is greater than 1, the time T0 taken to perform M measurements using the solution of the invention<T2, the measurement efficiency of the technical scheme of the invention is far better than that of the second technical scheme, and for burst signals with unknown signal occurrence time, frequency and duration, the detection interception capability of the technical scheme of the invention on the signals is better than that of the traditional technical scheme.
By adopting the technical scheme of the invention, the tunable local oscillator can perform tuning frequency stepping at the time of switching the frequency of the input signal, the residence time of each tuning frequency point is less than or equal to the residence time of the input signal at each frequency point, and after N times of stepping execution is finished, a complete frequency hopping signal stray spectrum can be constructed by using the statistical spectrum data of each stepping.
The invention controls the frequency tuning of the superheterodyne instrument according to the signal characteristics, and can quickly obtain interested signal spectrum data.
Drawings
Fig. 1 is a schematic block diagram of an intermediate frequency digital spectrum analyzer.
FIG. 2 shows the frequency switching time T of the local oscillator step tuningFTime graph of zero.
FIG. 3 shows the frequency switching time T of the local oscillator step tuningFTime relation graph with time not being zero.
FIG. 4 is a diagram of a broadband burst spectrum analyzer;
40-local oscillation unit; 41-superheterodyne frequency conversion receiving unit; 42-a filter; 43-ADC acquisition and pre-processing unit; 44-a spectral processing unit; 45-a signal feature extraction unit; 46-a scan controller; 47-display unit.
Fig. 5 is a schematic structural diagram of two-stage frequency conversion of the superheterodyne frequency conversion receiving unit and the filter.
Fig. 6 is a diagram of a signal feature extraction unit.
Detailed Description
The invention is described in further detail below with reference to the following figures and detailed description:
an input signal is input into a superheterodyne frequency conversion receiving unit 41, the superheterodyne frequency conversion receiving unit 41 mixes the input signal and a local oscillation signal with tunable frequency output by a local oscillation unit 40 into an intermediate frequency signal, the intermediate frequency signal is filtered by a filter 42 and then enters an ADC acquisition and preprocessing unit 43, the ADC acquisition and preprocessing unit 43 acquires and preprocesses the intermediate frequency signal, the preprocessing comprises digital frequency conversion and extraction filtering processing for realizing required analysis bandwidth and frequency resolution, the preprocessed formed baseband IQ signal data enters a frequency spectrum processing unit 44, and the baseband IQ signal data is displayed on a display unit 47 after being processed by the frequency spectrum processing unit 44; the scanning controller 46 controls the tunable local oscillator signal according to the characteristic information output by the signal characteristic extraction unit 45;
the superheterodyne frequency conversion receiving unit 41 is a one-stage or multi-stage frequency conversion unit.
The filter 42 is a cascade of a plurality of intermediate frequency filters, which include filters of each stage of the intermediate frequency chain and anti-aliasing filters of the ADC front end, wherein the bandwidth of each stage of the intermediate frequency filter is different, and the bandwidth of the intermediate frequency filter closer to the rf input end is larger. The first intermediate frequency filter bandwidth in fig. 5 is larger than the second intermediate frequency filter bandwidth, which is larger than the anti-aliasing filter bandwidth. The second intermediate frequency filter may also be combined with an anti-aliasing filter into one filter.
The spectrum processing unit 44 includes a windowed real-time FFT transform process and a spectrum statistical process performed on a plurality of frames of FFT spectrum data or a maximum hold process, an average process and a minimum hold process performed on a plurality of frames of FFT spectrum data. Meanwhile, a statistical spectrum track of all the measured frequency spans is constructed by the statistical spectrum track of each tuning measurement, or a maximum holding spectrum track of all the measured frequency spans is constructed by the maximum holding spectrum track of each tuning measurement, or an average processing spectrum track of all the measured frequency spans is constructed by the average processing spectrum track of each tuning measurement, or a maximum holding spectrum track of all the measured frequency spans is constructed by the minimum holding spectrum track of each tuning measurement,
and the display unit 47 is used for displaying one or more measurement tracks on a plurality of display windows simultaneously.
The signal feature extraction unit 45 extracts the basic features of the appearance time, the duration time, the disappearance time, and the repetition period of the signal to be detected according to the signal instantaneous power waveform, or extracts the basic features of the frequency switching time of the signal to be detected according to the signal instantaneous frequency feature. The input signal 48 of the signal characteristic extraction unit 45 may be a signal of an intermediate frequency link of any level or a radio frequency input signal.
One possible embodiment of the signal feature extraction unit 45 is shown in fig. 6. The input signal is passed through a power detector to obtain the instantaneous power of the signal, the instantaneous power is compared with a certain preset power threshold to generate a digital logic signal corresponding to the signal power change, the logic signal '1' represents that the signal power is higher than the power threshold, and the logic signal '0' represents that the signal power is lower than the power threshold. The digital logic signal is input into a programmable logic device, and the characteristics of signal duration, pulse repetition frequency and the like can be obtained through a counter.
The scan controller 46 controls the frequency switching of the tuned local oscillator and the residence time of a tuned frequency point according to the signal features extracted by the signal feature extraction unit 45, specifically, the time features of the appearance, disappearance or frequency switching of the detected signal can be used for controlling the local oscillator switching, and the time features of the duration and repetition period of the detected signal can be used for controlling the residence time of the local oscillator frequency point.
The broadband burst signal analysis method provided by the invention comprises the following steps:
step 1: determining a starting frequency F1 and a terminating frequency F2 required for analyzing the broadband burst signal, wherein the frequency span is larger than the analysis bandwidth RTBW of a spectrum analyzer, namely the frequency span is (F2-F1) > RTBW;
step 2: selecting a frequency resolution used for analyzing the broadband burst signal, and determining a STEP bandwidth STEP _ BW of each analysis according to the resolution and the analysis bandwidth of a spectrum analyzer, wherein the STEP _ BW is less than or equal to RTBW;
and step 3: the scanning control unit sets the output of the local oscillation unit to a first tuning frequency point, and a first section of frequency interval corresponding to frequency spectrum data from F1 to F2 can be obtained through the first tuning frequency point, wherein the starting frequency of the frequency interval is F1, and the ending frequency of the frequency interval is F1+ STEP _ BW;
and 4, step 4: the signal characteristic extraction unit extracts the signal residence time characteristic and transmits the time parameter to the scanning controller, the scanning controller determines the residence time of a first tuning frequency point of a local oscillator of the superheterodyne frequency conversion receiving unit, and the frequency spectrum processing unit performs frequency spectrum processing on output data of the ADC acquisition and preprocessing unit within the residence time to obtain frequency spectrum data of a first section of frequency interval;
and 5: the scanning controller controls the local oscillation unit to output switching from the first tuning frequency point to the second tuning frequency point, and the second tuning frequency point corresponds to a second section of frequency interval between F1 and F2, wherein the starting frequency of the second section of frequency interval is F1+ STEP _ BW, and the ending frequency is F1+2 + STEP _ BW;
step 6: the scanning controller controls the residence time of a second tuning frequency point of the local oscillator according to the signal characteristics output by the signal characteristic extraction unit, and the frequency spectrum processing unit performs frequency spectrum processing on the output data of the ADC acquisition and preprocessing unit in the residence time to obtain frequency spectrum data of a second section of frequency interval;
and 7: repeating the steps 3-6 until the measurement of all tuning frequency points is completed and all frequency intervals with the frequency span of F2-F1 are covered;
and 8: and the spectrum processing unit constructs the spectrum data corresponding to all the tuning frequency points into all the spectrum tracks with the frequency span of F2-F1.
According to the method provided by the invention, the spectrum processing comprises the following steps: obtaining a statistical spectrum track of a corresponding frequency interval in the residence time, or obtaining a maximum retention spectrum track of the corresponding frequency interval in the residence time, or obtaining a minimum retention spectrum track of the corresponding frequency interval in the residence time, or obtaining an average spectrum track of the corresponding frequency interval in the residence time, or simultaneously obtaining a plurality of spectrum tracks therein.
Assuming that it is desired to measure the spectrum of a burst signal with a wide bandwidth, the signal occupies a frequency span larger than the maximum analysis bandwidth of the ADC acquisition preprocessing module, and has a very short occurrence time and a long occurrence time interval. For the second technical solution, taking the example of performing N steps to complete one measurement, the time taken to perform one measurement in all frequency spans is ST ═ N × TP+(N-1)*TFWhere N denotes the number of steps, TPRepresenting the dwell time of each step, consisting essentially of the system rise time and acquisition time, TFIndicating the frequency switching time of the step tuning. Assuming that the software and hardware recovery time between two measurements is neglected, the time taken to perform M measurements over the entire frequency span is T2-M ST-M N TP+M*(N-1)*TF. Due to the time and signal at which the measurement is performedThe occurrence times are asynchronous, and even if M measurements are performed, there is no guarantee that the spectrum data at the time of the occurrence of the signal can be completely captured.
By adopting the technical scheme of the invention, the stay time of each step can be set to stay for at least one signal period, the maximum retention spectrum data measurement can be executed within the stay time, and after the execution of N steps is finished, the complete signal spectrum can be constructed by using the maximum retention spectrum data of each step. From the above analysis, it can be seen that the technical solution of the present invention has stronger analysis capability for executing wide bandwidth burst signals.
In addition, in the case of the present invention, it is assumed that M measurements are performed during the dwell time of each step, and that the time T0 taken to perform M measurements in the entire frequency span is M × N × TP+(N-1)*TF. Obviously, as long as N is greater than 1 and M is greater than 1, the time T0 taken to perform M measurements using the solution of the invention<T2, the measurement efficiency of the technical scheme of the present invention is far better than that of the second technical scheme, and for burst signals whose signal appearance time, frequency and duration are unknown, the detection interception capability of the technical scheme of the present invention on signals is still better than that of the conventional technical scheme.
In order to more clearly illustrate the beneficial effects of the technical solution of the present invention, the following is further described with reference to another more specific embodiment.
Assuming that it is desired to measure the spurious spectrum of a certain frequency hopping signal, the frequency hopping signal is switched between F1 and F2, and the frequency interval from F1 to F2 is greater than the analysis bandwidth of the superheterodyne instrument, for example, F1 is 1GHz, F2 is 2GHz, the acquisition and analysis bandwidth of the instrument is only 100MHz, and even sometimes, the analysis bandwidth of the instrument can only be set to a smaller bandwidth in order to achieve the required frequency resolution.
With the second solution, the obtained signal spectrum may include additional spectral components generated during frequency switching, and these spectral components are desirably removed. By adopting the technical scheme of the invention, the tunable local oscillator can perform tuning frequency stepping at the time of switching the frequency of the input signal, and the residence time of each tuning frequency point is less than or equal to that of the input signal at each frequency point. When N steps are completed, where N is 10, a complete frequency hopping signal spurious spectrum can be constructed by using the statistical spectrum data of each step.
The protection point of the invention is to protect a burst signal analysis method with wide bandwidth, and the bandwidth of the burst signal is larger than the analysis bandwidth of a superheterodyne instrument; the key point of the invention is that the frequency tuning of the superheterodyne instrument is controlled according to the signal characteristics, and interested signal spectrum data can be rapidly obtained. The input signal for extracting the signal characteristics is the signal of an intermediate frequency link or a radio frequency input signal of any level, and the bandwidth of the intermediate frequency link or the radio frequency link is far larger than the analysis bandwidth of the instrument.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.
Claims (6)
1. A broadband burst signal spectrum analyzer, characterized by: the system comprises a superheterodyne frequency conversion receiving unit, a local oscillation unit, a filter, an ADC (analog to digital converter) acquisition and preprocessing unit, a signal characteristic extraction unit, a scanning controller, a frequency spectrum processing unit and a display unit;
the superheterodyne frequency conversion receiving unit is configured to mix an input signal and a local oscillator signal with tunable frequency into an intermediate frequency signal;
the local oscillation unit is configured to be used for providing a local oscillation signal required by the superheterodyne frequency conversion receiving unit;
a filter configured to filter out an image signal;
an ADC acquisition and pre-processing unit configured for acquiring and pre-processing the intermediate frequency signal, the pre-processing including digital frequency conversion and decimation filtering processing for achieving a required analysis bandwidth and frequency resolution;
a signal feature extraction unit configured to extract basic features of an appearance time, a duration and a disappearance time of the input signal to be detected, a repetition period, or a frequency switching time of the input signal to be detected according to the signal instantaneous frequency feature;
the scanning controller is configured to control frequency switching of a tuned local oscillator and residence time of a certain tuned frequency point according to the signal features extracted by the signal feature extraction unit, specifically, the time features of appearance, disappearance or frequency switching of a detected signal can be used for controlling the switching of the local oscillator, and the time features of duration and repetition period of the detected signal can be used for controlling the residence time of the local oscillator;
a spectrum processing unit configured to perform a windowed real-time FFT transform process and a spectrum statistical process on a plurality of frames of FFT spectrum data or a maximum hold process, an average process, and a minimum hold process on a plurality of frames of FFT spectrum data; constructing spectrum tracks of all measured frequency spans from spectrum tracks of different frequency intervals measured for multiple times, specifically constructing a statistical spectrum track of all measured frequency spans from a statistical spectrum track of each step measurement, or constructing a maximum retention spectrum track of all measured frequency spans from a maximum retention spectrum track of each step measurement, or constructing an average processing spectrum track of all measured frequency spans from an average processing spectrum track of each step measurement, or constructing a minimum retention spectrum track of all measured frequency spans from a minimum retention spectrum track of each step measurement;
a display unit configured to simultaneously display the statistical spectrum locus, the maximum-maintained spectrum locus, the average spectrum locus or the minimum-maintained spectrum locus in a multi-window form;
the superheterodyne frequency conversion receiving unit mixes an input signal and a local oscillation signal provided by the local oscillation unit into an intermediate frequency signal, the intermediate frequency signal enters an ADC (analog to digital converter) acquisition and preprocessing unit after being filtered by a filter, the ADC acquisition and preprocessing unit acquires and preprocesses the intermediate frequency signal, the preprocessing comprises digital frequency conversion and extraction filtering processing for realizing required analysis bandwidth and frequency resolution, baseband IQ signal data formed after preprocessing enters a frequency spectrum processing unit, and the baseband IQ signal data is displayed on a display unit after being processed by the frequency spectrum processing unit; the scanning controller controls the local oscillation unit to output expected local oscillation signals according to the characteristic information output by the signal characteristic extraction unit.
2. The wideband burst signal spectrum analyzer of claim 1, wherein: the superheterodyne frequency conversion receiving unit is a one-stage or multi-stage frequency conversion unit.
3. The wideband burst signal spectrum analyzer of claim 1, wherein: the filter is formed by cascading a plurality of intermediate frequency filters, the intermediate frequency filters comprise a filter of each stage of intermediate frequency link and an anti-aliasing filter at the front end of the ADC, the bandwidth of each stage of intermediate frequency filter is different, and the bandwidth of the intermediate frequency filter closer to the radio frequency input end is larger.
4. The wideband burst signal spectrum analyzer of claim 1, wherein: the input signal is a signal of an intermediate frequency link of any stage or a radio frequency input signal.
5. A broadband burst signal analysis method, characterized by: the wideband burst signal spectrum analyzer as claimed in claim 1, comprising the steps of:
step 1: determining a starting frequency F1 and a terminating frequency F2 required for analyzing the broadband burst signal, wherein the frequency span is larger than the analysis bandwidth RTBW of a spectrum analyzer, and the frequency span is F2-F1, F2-F1> RTBW;
step 2: selecting a frequency resolution used for analyzing the broadband burst signal, and determining a STEP bandwidth STEP _ BW of each analysis according to the resolution and the analysis bandwidth of a spectrum analyzer, wherein the STEP _ BW is less than or equal to RTBW;
and step 3: the scanning controller sets the output of the local oscillation unit to a first tuning frequency point, and a first section of frequency interval corresponding to frequency spectrum data from F1 to F2 can be obtained through the first tuning frequency point, wherein the starting frequency of the frequency interval is F1, and the ending frequency of the frequency interval is F1+ STEP _ BW;
and 4, step 4: the signal characteristic extraction unit extracts the signal residence time characteristic and transmits the time parameter to the scanning controller, the scanning controller determines the residence time of a first tuning frequency point of a local oscillator of the superheterodyne frequency conversion receiving unit, and the frequency spectrum processing unit performs frequency spectrum processing on output data of the ADC acquisition and preprocessing unit within the residence time to obtain frequency spectrum data of a first section of frequency interval;
and 5: the scanning controller controls the output of the local oscillation unit to be switched from a first tuning frequency point to a second tuning frequency point, and a second frequency interval corresponding to frequency spectrum data from F1 to F2 can be obtained through the second tuning frequency point, wherein the starting frequency of the second frequency interval is F1+ STEP _ BW, and the ending frequency of the second frequency interval is F1+2 STEP _ BW;
step 6: the scanning controller controls the residence time of the second tuning frequency point according to the signal characteristics output by the signal characteristic extraction unit, and the frequency spectrum processing unit performs frequency spectrum processing on the output data of the ADC acquisition and preprocessing unit within the residence time to obtain frequency spectrum data of a second section of frequency interval;
and 7: repeating the steps 3-6 until the measurement of all tuning frequency points is completed and all frequency intervals with the frequency span of F2-F1 are covered;
and 8: and the spectrum processing unit constructs the spectrum data corresponding to all the tuning frequency points into all the spectrum tracks with the frequency span of F2-F1.
6. The wideband burst signal analysis method of claim 5, wherein: the spectrum processing described in steps 4 and 6 includes: obtaining a statistical spectrum track of a corresponding frequency interval in residence time, or obtaining a maximum retention spectrum track of the corresponding frequency interval in residence time, or obtaining a minimum retention spectrum track of the corresponding frequency interval in residence time, or obtaining an average spectrum track of the corresponding frequency interval in residence time, or simultaneously obtaining a plurality of spectrum tracks.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911169851.8A CN110988473B (en) | 2019-11-26 | 2019-11-26 | Broadband burst signal spectrum analyzer and broadband burst signal analysis method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911169851.8A CN110988473B (en) | 2019-11-26 | 2019-11-26 | Broadband burst signal spectrum analyzer and broadband burst signal analysis method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110988473A CN110988473A (en) | 2020-04-10 |
| CN110988473B true CN110988473B (en) | 2021-08-17 |
Family
ID=70086852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911169851.8A Active CN110988473B (en) | 2019-11-26 | 2019-11-26 | Broadband burst signal spectrum analyzer and broadband burst signal analysis method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110988473B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112836169A (en) * | 2021-03-04 | 2021-05-25 | 天津光电通信技术有限公司 | FFT (fast Fourier transform) spectrum data processing method and device based on high-speed acquisition |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102183691A (en) * | 2011-03-22 | 2011-09-14 | 安徽白鹭电子科技有限公司 | Double-tuned microwave spectrum analyzer |
| JP2016121894A (en) * | 2014-12-24 | 2016-07-07 | アイコム株式会社 | Spectrum analyzer and display control method therefor |
| CN106353594A (en) * | 2016-08-15 | 2017-01-25 | 中国电子科技集团公司第四十研究所 | Spectrum analyzer system with fast multi-resolution and method |
| CN106405235A (en) * | 2016-10-17 | 2017-02-15 | 深圳市鼎阳科技有限公司 | Spectrum analyzer and data processing method thereof |
-
2019
- 2019-11-26 CN CN201911169851.8A patent/CN110988473B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102183691A (en) * | 2011-03-22 | 2011-09-14 | 安徽白鹭电子科技有限公司 | Double-tuned microwave spectrum analyzer |
| JP2016121894A (en) * | 2014-12-24 | 2016-07-07 | アイコム株式会社 | Spectrum analyzer and display control method therefor |
| CN106353594A (en) * | 2016-08-15 | 2017-01-25 | 中国电子科技集团公司第四十研究所 | Spectrum analyzer system with fast multi-resolution and method |
| CN106405235A (en) * | 2016-10-17 | 2017-02-15 | 深圳市鼎阳科技有限公司 | Spectrum analyzer and data processing method thereof |
Non-Patent Citations (1)
| Title |
|---|
| "频谱分析仪综合实验系统设计和应用";董英雷 等;《实验技术与管理》;20190731;第97-102页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110988473A (en) | 2020-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8849213B2 (en) | Integrated circuit for signal analysis | |
| US8447252B2 (en) | Adaptive channel scanning for detection and classification of RF signals | |
| CN101300498B (en) | Wide-bandwidth spectrum analysis of transient signals using a real-time spectrum analyzer | |
| EP2219039B1 (en) | Amplitude discrimination using the frequency mask trigger | |
| US8988272B2 (en) | Digital receiver techniques in radar detectors | |
| EP2219037B1 (en) | Time qualified frequency mask trigger | |
| WO2018032645A1 (en) | Wideband wide-frequency agile signal measurement instrument and measurement method | |
| Al Adnani et al. | Spectrum analyzers today and tomorrow: part 1 towards filterbanks-enabled real-time spectrum analysis | |
| CN106353594B (en) | A kind of fast multiresolution frequency spectrum analysis system and method | |
| US9450598B2 (en) | Two-stage digital down-conversion of RF pulses | |
| CN110988473B (en) | Broadband burst signal spectrum analyzer and broadband burst signal analysis method | |
| US8064560B2 (en) | Systems and methods for detecting a signal across multiple Nyquist bands | |
| CN110045256A (en) | A kind of SHF frequency range local discharge signal reception circuit | |
| CN103297073A (en) | Wideband receiver | |
| CN109541307A (en) | The circuit structure of UWB signal analysis function is realized based on Single Conversion technology | |
| CN106896268A (en) | A kind of frequency expansion device, the spectrum analyzer for possessing spread spectrum function | |
| JP4176479B2 (en) | Frequency analysis method, frequency analysis apparatus, and spectrum analyzer | |
| CN103941092B (en) | A kind of device of the quick scanning survey of frequency domain | |
| CN106374946B (en) | A kind of receiver radio frequency panoramic scanning circuit | |
| Keller | A new concept for a wideband FFT-Based EMI receiver | |
| JP4260344B2 (en) | Spectrum analyzer | |
| CN112068105B (en) | System and method for analyzing signal spectrum of frequency modulation continuous wave laser radar receiver | |
| JPH10126217A (en) | Decimation filter | |
| CN105356954A (en) | Method and system for detecting chirp signal power | |
| Braun | Spectrum analysis and EMI measurements based on time-domain methods |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 266555 No. 98 Xiangjiang Road, Huangdao District, Qingdao City, Shandong Province Patentee after: CLP kesiyi Technology Co.,Ltd. Address before: 266555 No. 98 Xiangjiang Road, Huangdao District, Qingdao City, Shandong Province Patentee before: CHINA ELECTRONICS TECHNOLOGY INSTRUMENTS Co.,Ltd. |
|
| CP01 | Change in the name or title of a patent holder |