A low sampling rate electromagnetic pulse amplitude and width measurement method

Abstract

The application discloses a low sampling rate electromagnetic pulse amplitude and width measurement method, which converts pulse width measurement into pulse amplitude and in-pulse area measurement. Amplitude value measurement is that after a pulse passes through a peak detection circuit, the pulse is sampled by an analog-to-digital converter, and the maximum value obtained by sampling is taken as an amplitude value; area value measurement is that after a pulse passes through an integration circuit, the pulse is sampled by an analog-to-digital converter, and the maximum value obtained by sampling is taken as an in-pulse area value after processing. Meanwhile, the application corrects the pulse detection amplitude to obtain a real pulse amplitude in view of the situation that peak detection causes detection amplitude distortion of a nanosecond-level narrow pulse. The method can measure the pulse width under a low sampling rate condition, corrects the amplitude measurement of detection distortion, and realizes accurate measurement and monitoring of the pulse width and amplitude.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic pulse signal measurement technology, specifically relating to a method for measuring the amplitude and width of electromagnetic pulses at low sampling rates. Background Technology

[0002] With the increasing number of frequency-using devices in daily life, the electric field environment in which these devices operate is becoming increasingly complex in multiple dimensions, including time, frequency, space, and energy. This includes increasingly dense signals, wide spectrum occupancy, and complex properties, which necessitates understanding the characteristics of the electromagnetic environment and real-time monitoring of the electromagnetic environment at the device's location. Due to the wide bandwidth and narrow pulse width of UWB pulse signals (ranging from 0.3ns to 5ns), real-time measurement of such signals has always been a challenge for electromagnetic environment monitoring.

[0003] Pulse width measurement involves measuring the time interval between the rising and falling edges of a pulse. Currently, there are three main methods for pulse width measurement both domestically and internationally: oscilloscope measurement, counter measurement, and high-speed acquisition. The oscilloscope method plots the waveform of the measured pulse signal over time and calculates the pulse width from the waveform. This method can accurately measure most transient signals, but it is difficult to digitize and integrate into a system. The counter method uses the measured pulse as the control signal. When the rising edge of the measured pulse arrives, it triggers a counter that counts a reference clock signal. The counter stops counting when the falling edge of the measured pulse arrives or the rising edge of the next pulse arrives. The counter method is limited by the reference clock frequency and suffers from large measurement errors at low clock frequencies. The high-speed acquisition method uses a high-speed analog-to-digital converter to acquire signal data. For narrow pulse measurements, a very high sampling rate is required. However, this high sampling rate leads to significant data redundancy and high power consumption. Furthermore, this method also faces the bottleneck of balancing sampling rate and measurement error.

[0004] Furthermore, pulse amplitude is one of the most important parameters of a pulse, characterizing its energy information. There are two main methods for pulse amplitude measurement: oscilloscope measurement and high-speed acquisition methods. Oscilloscope measurement plots the waveform of the pulse signal under test over time and calculates the pulse amplitude from the waveform. This method can accurately measure most transient signals, but it is difficult to digitize and integrate into a system. High-speed acquisition methods use high-speed analog-to-digital converters to acquire signal data. For narrow pulse measurements, a very high sampling rate is required. High sampling rates lead to significant data redundancy and high power consumption. This method also faces the bottleneck of a trade-off between sampling rate and measurement error. Methods for measuring pulses at low sampling rates include uncorrelated reception and peak detection. Low sampling rate refers to a rate lower than the Nyquist sampling rate. Uncorrelated reception uses an integrator circuit to determine the presence of a signal by passing it through a threshold, which is unsuitable for pulse amplitude measurement. Peak detection is a better method for measuring pulse amplitude at low sampling rates. It utilizes the charging and discharging characteristics of a capacitor and the unidirectional conduction characteristics of a diode to maintain the amplitude of the pulse's maximum value in the time domain. However, peak detection has a response time due to the influence of parasitic parameters, which leads to amplitude distortion when measuring narrow pulses, making it impossible to obtain the true pulse amplitude. Summary of the Invention

[0005] Based on the above analysis, the present invention provides a method for measuring the amplitude and width of electromagnetic pulses at low sampling rates, in order to solve the technical problem of the limitation contradiction between sampling rate and pulse width measurement error. The measurement method of the present invention can measure the width of narrow pulses at low sampling rates, and can correct the amplitude measurement of detection distortion, thereby realizing the measurement and monitoring of the width and amplitude of narrow pulses.

[0006] This invention discloses a method for measuring the amplitude and width of electromagnetic pulses with a low sampling rate, the specific steps of which are as follows:

[0007] Establish an equivalent model relating pulse width to pulse amplitude and pulse area;

[0008] ;

[0009] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k For waveform coefficients;

[0010] The pulse to be tested is divided into two sub-pulses;

[0011] One sub-pulse enters the peak detection circuit to obtain the detection output signal; the amplitude of the detected signal output signal is acquired by an analog-to-digital converter, and the maximum value of the acquired detection signal amplitude is taken as the pulse amplitude. A ;

[0012] Another sub-pulse enters the integrator circuit to obtain the integrated output signal; the integrated output signal is sampled by an analog-to-digital converter to obtain the amplitude of the integrated signal. The maximum value of the integrated output signal is the maximum value of the integrated signal amplitude, and the maximum value of the sampled integrated signal amplitude is used as the pulse area. ;

[0013] Based on an equivalent model relating pulse width to pulse amplitude and pulse area, the maximum value of the detected signal amplitude and the pulse area of ​​the pulse under test are obtained, thus yielding the pulse amplitude. A and pulse width .

[0014] Optionally, the amplitude of the detected signal is obtained by sampling the detected output signal using an analog-to-digital converter, and the maximum value of the sampled detected signal amplitude is used. Obtain pulse amplitude A The expression is:

[0015] ;

[0016] In the formula, The maximum detector signal amplitude; A The amplitude of the pulse; e It is the natural logarithm; R S This represents the series resistance value of the diode in the peak detection circuit; This is the value of the charging capacitor for the peak detection circuit.

[0017] Optionally, the integral output signal is sampled by an analog-to-digital converter to obtain the integral signal amplitude, and the maximum value of the integral output signal is the maximum value of the integral signal amplitude. The maximum value of the integral signal amplitude obtained by sampling. As pulse area The expression is:

[0018] ;

[0019] In the formula, For the integrator circuit, a series resistor is used. The capacitor is used to charge the integrating circuit.

[0020] Optionally, in step 3, when the charging constant of the integrator circuit is much larger than the input pulse width, the expression for the integrated output signal is:

[0021] ;

[0022] In the formula, S o ( t )for tThe integral output signal at time t; For the integrator circuit, a series resistor is used. A capacitor for charging the integrating circuit; For time t Integrate points; For time t For the sub-pulse of the integral variable.

[0023] Optionally, it is used to obtain the pulse width when the pulse is a rectangular pulse or a Gaussian pulse;

[0024] For a rectangular pulse, the equivalent model expression for the relationship between the rectangular pulse width and the pulse amplitude and pulse area is:

[0025] ;

[0026] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k =1;

[0027] For a Gaussian pulse, the equivalent model expression for the relationship between the Gaussian pulse width and the pulse amplitude and pulse area is:

[0028] ;

[0029] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k = .

[0030] The present invention has at least the following beneficial effects:

[0031] (1) The method of the present invention converts the time domain parameter measurement (directly measuring the pulse width) into the energy domain parameter measurement (measuring the amplitude and area of ​​the pulse), which greatly reduces the sampling rate and thus reduces the system measurement and monitoring costs;

[0032] (2) The method of the present invention corrects the distorted detection amplitude by combining the amplitude and area of ​​the pulse, which not only reduces the sampling rate for narrow pulse measurement, but also breaks through the response time limit of peak detection and significantly reduces the lower limit of pulse measurement.

[0033] (3) The method of the present invention can achieve high-precision measurement at a low cost, without the need for an oscilloscope or high-speed acquisition device, is portable and can be used in real time.

[0034] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained from the description and accompanying drawings, which are particularly pointed out. Attached Figure Description

[0035] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0036] Figure 1 This is a flowchart of the measurement method of the present invention;

[0037] Figure 2(a) and (b) show the equivalent models of Gaussian pulses and rectangular pulses;

[0038] Figure 3 (a) and (b) are schematic diagrams of the amplitude measurement circuit and principle of the present invention;

[0039] Figure 4 (a) and (b) are schematic diagrams of the area measurement circuit and principle of the present invention;

[0040] Figure 5 This is a schematic diagram showing the actual measurement results using the measurement method of the present invention. Detailed Implementation

[0041] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0042] A specific embodiment of the present invention, such as Figures 1-5 As shown, a method for measuring the amplitude and width of electromagnetic pulses with a low sampling rate is disclosed, and in particular, a method for measuring the amplitude and width of narrow pulses with a low sampling rate is disclosed. The specific steps are as follows:

[0043] Step 1: Establish an equivalent model relating pulse width to pulse amplitude and pulse area;

[0044] ;

[0045] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k These are waveform coefficients.

[0046] For example, the equivalent model expression for the relationship between the rectangular pulse width and the pulse amplitude and pulse area is:

[0047] ;

[0048] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k =1.

[0049] The equivalent model expression for the relationship between Gaussian pulse width, pulse amplitude, and pulse area is:

[0050] ;

[0051] in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k = .

[0052] Step 2: Divide the pulse into two sub-pulses; one sub-pulse enters the peak detection circuit to obtain the detection output signal; use an analog-to-digital converter to collect the detection signal amplitude of the detection output signal, and take the maximum value of the collected detection signal amplitude as the pulse amplitude;

[0053] Peak detection circuit diagram as follows Figure 3 As shown in (a), the peak detection circuit includes a detector diode and a forward resistor. r Charging capacitor and load resistance . Figure 3 (b) describes the principle of peak detection amplitude measurement when the Gaussian pulse is the input pulse. The solid black line represents the input Gaussian pulse, and the dashed black line represents the output pulse of the peak detection circuit. In the figure, during the pulse rising edge phase, the forward resistance of the detection diode is... r When the circuit is turned on, the peak detection circuit operates in the charging state and supplies power to the charging capacitor. During charging, the charging circuit time constant is... This ensures that the detected signal remains consistent with the original signal; during the falling edge phase, the forward resistance of the detector diode... r At the cutoff, the peak detection circuit is in a discharging state, and the charging capacitor... Through load resistance Discharge occurs, at which point the discharge circuit time constant... for This causes the amplitude of the detected signal to decrease slowly. During this slow decrease phase, the maximum amplitude of the detected signal is obtained by sampling the output signal through an analog-to-digital converter. The maximum value of the amplitude of the sampled detector signal Obtain pulse amplitude A Pulse amplitude A The expression to retrieve is:

[0054] ;

[0055] In the formula, The maximum detector signal amplitude; A The amplitude of the pulse; e It is the natural logarithm; R S This represents the series resistance value of the diode in the peak detection circuit; This is the value of the charging capacitor for the peak detection circuit.

[0056] This invention addresses the issue of amplitude distortion in nanosecond-level narrow pulse detection caused by peak detection by correcting the pulse detection amplitude to obtain the true pulse amplitude, thus enabling accurate acquisition of the pulse amplitude.

[0057] Step 3: Enter the other sub-pulse from Step 2 into the integrating circuit to obtain the integrated output signal; use an analog-to-digital converter to collect the amplitude of the integrated output signal, and use the maximum value of the collected integrated signal amplitude as the pulse area.

[0058] Integrating circuits such as Figure 4 As shown in (a), the integrating circuit includes a series resistor. Charging capacitor and load resistance . Figure 4 (b) illustrates the principle of area measurement of the integrator circuit when the Gaussian pulse is the input pulse. The solid black line represents the input Gaussian pulse, and the dashed black line represents the output waveform of the integrator circuit. The constant during the charging of the integrator circuit is... Much larger than the input pulse width Preferably, when the integrating circuit is charging, the constant is... When the input pulse width is greater than 10 times, the integral output signal is expressed as follows:

[0059] ;

[0060] In the formula, S o ( t )for t The integral output signal at time t; For the integrator circuit, a series resistor is used. A capacitor for charging the integrating circuit; dτ For time t Integrate points; S ( τ ) as time tFor the sub-pulse of the integral variable.

[0061] The amplitude of the integral signal is obtained by sampling the integral output signal using an analog-to-digital converter, and the maximum value of the integral output signal is also obtained. s 0( t ) max The maximum value of the integral signal amplitude The maximum value of the integral signal amplitude obtained by sampling. As pulse area Pulse area The expression to retrieve is:

[0062] ;

[0063] Step 4: Based on the equivalent model of the relationship between pulse width, pulse amplitude, and pulse area obtained in Step 1, and the maximum value of the detected signal amplitude obtained in Steps 2 and 3. and pulse area Obtain pulse amplitude A and pulse width .

[0064] Understandably, obtaining the maximum value of the detector signal amplitude is the goal. and the maximum value of the integral signal amplitude Combine the equivalent model of the relationship between pulse width, pulse amplitude, and pulse area in step 1, and the pulse amplitude in step 2. A Obtain the pulse area from the expression and step 3. Obtain the pulse amplitude from the expression A and pulse width .

[0065] The effectiveness and advancement of the method of the present invention will be further explained below with reference to experiments.

[0066] The experimental circuit and equipment were built according to the working principle diagram. The SD101AW detector diode was used for sampling, with a series resistance of 2 ohms and a junction capacitance of 2.2 × 10⁻⁶. -12 F, operating at high frequency. The analog-to-digital converter has a sampling rate of 10MHz, at which direct sampling of the input pulse is not possible. A rectangular pulse was selected as the input signal for testing; two 0.68V / 18.8ns rectangular pulses appeared at 1µs and 3µs. The acquisition results are as follows... Figure 5 As shown.

[0067] Figure 5 The results are shown as direct sampling and 10Msps sampling results after peak detection and integration of the pulse. The vertical bars represent sampling points, and the height of the bars represents the sampled values. As can be seen, Figure 5In the direct sampling results, only one pulse was detected, the second pulse was lost, and the pulse width measurement error of the first pulse was 100ns. Figure 5 After peak detection and integration, the pulses were sampled at 10 Msps. It can be seen that both pulses were detected, and their amplitudes and pulse areas can be read. After calculation, the amplitudes and pulse widths of the two pulses are 0.713V / 17.01ns and 0.711V / 17.00ns, respectively.

[0068] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the amplitude and width of electromagnetic pulses with a low sampling rate, characterized in that, The specific steps are as follows: Establish an equivalent model relating pulse width to pulse amplitude and pulse area; ； in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k For waveform coefficients; The pulse to be tested is divided into two sub-pulses; One sub-pulse enters the peak detection circuit to obtain the detection output signal; the amplitude of the detected signal output signal is acquired by an analog-to-digital converter, and the maximum value of the acquired detection signal amplitude is taken as the pulse amplitude. A ; Another sub-pulse enters the integrator circuit to obtain the integrated output signal; the integrated output signal is sampled by an analog-to-digital converter to obtain the amplitude of the integrated signal. The maximum value of the integrated output signal is the maximum value of the integrated signal amplitude, and the maximum value of the sampled integrated signal amplitude is used as the pulse area. ; Based on an equivalent model relating pulse width to pulse amplitude and pulse area, the maximum value of the detected signal amplitude and the pulse area of ​​the pulse under test are obtained, thus yielding the pulse amplitude. A and pulse width .

2. The measurement method according to claim 1, characterized in that, The amplitude of the detected signal is obtained by sampling the output signal through an analog-to-digital converter, and the maximum value of the sampled amplitude is used. Obtain pulse amplitude A The expression is: ； In the formula, The maximum detector signal amplitude; A The amplitude of the pulse; e It is the natural logarithm; R S This represents the series resistance value of the diode in the peak detection circuit; This is the charging capacitor value of the peak detection circuit.

3. The measurement method according to claim 1, characterized in that, The amplitude of the integral signal is obtained by sampling the integral output signal using an analog-to-digital converter. The maximum value of the integral output signal is the maximum value of the integral signal amplitude. The maximum value of the integral signal amplitude obtained by sampling. As pulse area The expression is: ； In the formula, For the series resistance of the integrating circuit; This is the charging capacitor for the integrating circuit.

4. The measurement method according to claim 1, characterized in that, In step 3, when the charging constant of the integrator circuit is greater than 10 times the input pulse width, the expression for the integrated output signal is: ； In the formula, S o ( t )for t The integral output signal at time t; For the series resistance of the integrating circuit; The charging capacitor for the integrating circuit; For time t Integrate points; For time t For the sub-pulse of the integral variable.

5. The measurement method according to any one of claims 1-4, characterized in that, Used to obtain the pulse width of a rectangular pulse or a Gaussian pulse; For a rectangular pulse, the equivalent model expression for the relationship between the rectangular pulse width and the pulse amplitude and pulse area is: ； in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k =1; For a Gaussian pulse, the equivalent model expression for the relationship between the Gaussian pulse width and the pulse amplitude and pulse area is: ； in, W , A and S These represent pulse width, pulse amplitude, and pulse area, respectively. k = .

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