CN-121978405-A - Transient signal real-time capturing method based on frequency domain detection in digital oscilloscope

Abstract

The invention discloses a transient signal real-time capturing method based on frequency domain detection in a digital oscilloscope, which utilizes an improved WOLA structure to carry out multi-channel spectrum analysis and processing on signals, the processed signals are selected to be in different capturing methods according to the initial frequency position and signal limit of effective signals, fourier transformation and characteristic comparison are carried out on the signals containing effective signal frequency bands, and the frequency bands not containing effective signals are directly compared with the maximum value and the minimum value of normal signals, so that transient signal capturing of different frequency bands of the signals is realized.

Inventors

• LIU XUETAO
• ZHANG QINCHUAN
• QIU DUYU
• YANG KUOJUN
• Ye Pi
• WANG HONGJIE
• GE HAIPENG
• HUANG CHUAN
• PAN ZHIXIANG
• HUANG WUHUANG
• ZHAO YU

Assignees

• 电子科技大学

Dates

Publication Date

20260505

Application Date

20260121

Claims (1)

1. 1. A transient signal real-time capturing method based on frequency domain detection in a digital oscilloscope is characterized by comprising the following steps: (1) Powering up the digital oscilloscope and setting the digital oscilloscope to a normal acquisition mode; (2) Inputting the normal signal to a digital oscilloscope, and acquiring D paths of sampling data through ADC in an acquisition system , The serial number index of each sampling point in the sampling data is used for indexing; (3) Carrying out channelized spectrum analysis processing on the sampled data through a WOLA structure; (3.1), setting sample data Length of interception of (2) Sampling data Move D data backward from the first The initial interception length of the data is Is a sampling data of (a) , ; (3.2) Sampling data Carrying out channelized digital filtering; Let the coefficients of the prototype low-pass filter be Corresponding bandwidth is , wherein, In order to acquire the sampling rate of the system, Is the number of channels; Record the first The sampled data after D data translation interception in each channel is that Sampling data using a channelized digital filter Weighted filtering is carried out to obtain a filtered signal : ; (3.3) Filtering the signal According to In increasing order of The points being divided into a group of Then sum the components of the same column to obtain the vector with the length of Is a signal of (2) , ; (3.4) Pair signal Parallel DFT and time domain modulation are carried out in the digital domain to obtain a channelized low-frequency signal ; (4) Acquiring an effective channel; the frequency range for each channel is calculated according to the following formula: ; Extracting the frequency of the input normal signal Determining the frequency The frequency range of which channel is located, recording the corresponding channel number, and setting the channel as an effective channel; (5) Fast fourier transform; recording the output low frequency signal in the effective channel as And performing fast Fourier transform to obtain signal spectrum, and recording maximum amplitude in the spectrum Minimum amplitude And corresponding frequencies 、 ; (6) Extracting the amplitude range of the low-frequency signal output in the non-effective channel; By low-frequency signals The amplitude range is obtained through an extremum detection module: ; (7) Switching the digital oscilloscope to a transient signal capturing mode, inputting a signal to be detected, processing according to the steps (2) - (6), and recording the maximum amplitude of a frequency spectrum obtained under the signal to be detected Minimum amplitude And corresponding frequencies 、 ; (8) Setting a capturing zone bit; (8.1) judging abnormal boundary crossing; frequency comparison if And is also provided with If the frequency is judged not to be out of range, a flag bit is output Otherwise, judging that the frequency is out of range ; Amplitude comparison if And is also provided with If the amplitude is judged not to be out of range, outputting a zone bit Otherwise, judge that the amplitude is beyond ; When the frequency is out of range Or amplitude out of range When the capturing zone bit is set Otherwise, the device can be used to determine whether the current, ; (8.2) Judging the amplitude fluctuation range of the signal to be tested; under the signal to be measured, traversing the amplitude range of the low-frequency signal output in each non-effective channel Comparing the signal with the amplitude range of the corresponding channel under the normal signal, and if the signal amplitude range of one channel under the signal to be detected exceeds, setting the capture zone bit as Otherwise, the capture flag bit is set to ; (9) Capturing transient signals; When (when) Or (b) And when the digital oscilloscope starts transient signal capturing, storing the transient signal into the RAM, and finally transmitting the transient signal to the upper computer for display.

Description

Transient signal real-time capturing method based on frequency domain detection in digital oscilloscope Technical Field The invention belongs to the technical field of digital oscilloscopes, and particularly relates to a transient signal real-time capturing method based on frequency domain detection in a digital oscilloscopes. Background With the rapid development of the fields of wireless communication, radar detection, spectrum monitoring and the like, the complexity of signals acquired by a high-speed acquisition system in a time-frequency domain is increasing. Modern communication systems widely employ frequency hopping, spreading, chirp, and various digital modulation techniques, so that signals exhibit complex characteristics such as dynamic distribution, fast switching, and broadband coverage in the frequency domain. Key features such as instantaneous burst, spectrum distortion, specific mode deletion and the like of the signals in the transmission process often bear important information such as system state, interference information or threat signals. Therefore, in a high-speed acquisition system, real-time and accurate capturing of transient signals becomes an important guarantee for the functional integrity and reliability of the system. Traditional signal capturing methods of digital oscilloscopes mainly rely on time domain triggering mechanisms, such as edge triggering, pulse width triggering or pattern triggering. Such methods are applicable to simple signals with significant time domain characteristics, but have significantly insufficient acquisition capability for complex signals with significant frequency domain dynamics. For example, when receiving a frequency hopping signal, the time domain trigger cannot effectively follow the frequency hopping rule, and when facing transient interference or in-band spectrum mutation, the time domain waveform may not be obviously distorted, so that the key signal segment is ignored by the system. Frequency domain analysis provides a new technological path for transient signal acquisition. Through real-time spectrum analysis, the acquisition system can identify the frequency distribution, the power spectral density and the change rule of the frequency spectrum along with time. However, the direct implementation of full-bandwidth and high-resolution frequency domain processing in a high-speed acquisition environment faces serious challenges, namely, on one hand, the traditional FFT processing has huge calculation amount of full-bandwidth data and is difficult to meet the real-time requirement, and on the other hand, the frequency domain characteristics of transient signals often have locality and time-varying properties, and acquisition omission or false alarms are easily caused by simply adopting a fixed threshold value or global template matching. The existing signal capturing scheme based on frequency domain detection is generally difficult to consider processing speed, capturing precision and algorithm flexibility in a hardware environment with limited resources. Especially in the application scene of high sampling rate and wide bandwidth, the throughput of signal data is extremely high, if the indiscriminate frequency domain processing is carried out on all data, the system load is too high, the response is delayed, and the timely capturing of transient or non-stable signals is difficult to realize. Meanwhile, the frequency domain structure of the transient signal may evolve with time, and the frequency spectrum analysis method of the fixed parameter cannot adaptively track the change of the signal characteristics, so that the practicability and the robustness of the acquisition system are further limited. Therefore, the frequency domain capturing technology for complex signals in the high-speed acquisition system of the current digital oscilloscope still has obvious defects, and a solution capable of realizing efficient, intelligent and self-adaptive frequency domain analysis and capturing under the condition of limited hardware resources is lacking. The field needs a new frequency domain capturing method capable of considering real-time processing capability, accurate capturing performance and resource efficiency, so as to meet urgent requirements of a modern high-speed acquisition system on real-time capturing of transient signals. Disclosure of Invention The invention aims to overcome the defects of the prior art, provides a transient signal real-time capturing method based on frequency domain detection in a digital oscilloscope, the signals are subjected to multi-channel spectrum processing by utilizing a parallel WOLA (Weigthed OverLap-Add) structure, the processed normal signals and signals to be detected are compared on a frequency domain, and capture is carried out according to the difference of the spectrum characteristic information. In order to achieve the above purpose, the invention provides a transient signal real-time capturing method