CN103941280B - Based on the digital core pulse Gauss manufacturing process of Impulse invariance procedure - Google Patents

Abstract

The invention discloses a kind of digital core pulse Gauss manufacturing process based on Impulse invariance procedure, comprise: according to the circuit of simulation Gauss formation system, obtain the differential equation of circuit system input signal and output signal, the differential equation is derived by frequency-domain analysis, obtains the unit impulse response of simulation Gaussian Systems; The frequency response of analysis mode Gauss formation system, and frequency that simulation Gauss formation system is sampled is determined according to the spectral range of frequency response; Simulation Gauss formation system Impulse invariance procedure is converted to numeric field by analog domain, obtains the unit impulse response of digital Gaussian formation system, containing the forming parameter that can adjust waveform widths in described impulse response; Forming parameter in selected impulse response, and the unit impulse response of corresponding digital Gaussian formation system is determined according to selected forming parameter value; The unit impulse response of the core pulse signal and digital Gaussian formation system that are input to digital Gaussian formation system is carried out Convolution sums computing, realizes digital core pulse Gauss and be shaped.

Description

Based on the digital core pulse Gauss manufacturing process of Impulse invariance procedure

Technical field

The Gauss that the present invention relates to digital core pulse in radioactivity survey is shaped, and particularly relates to a kind of digital core pulse Gauss manufacturing process based on Impulse invariance procedure.

Background technology

In nuclear spectrum measurement system, reduce pulse pile-up for convenience of subsequent conditioning circuit process and analysis and improve signal to noise ratio (S/N ratio), the signal shaping that detector need be exported be suitable waveform.The signal to noise ratio (S/N ratio) of Gaussian waveform is high, top is more smooth, ballistic deficit is less, and therefore the normal signal shaping exported by detector is Gauss or accurate Gaussian waveform.Simulation Gauss is shaped and simulation Sallen-Key wave filter can be used to realize, but the formation system realized due to mimic channel, changing over shape parameter must adjust hardware; Digital forming does not then need adjustment System hardware, has higher dirigibility and stability, and digital Gaussian shaping Algorithm becomes the focus of Nuclear signal processing research in recent years.

Summary of the invention

For solving the problems of the technologies described above, the object of this invention is to provide a kind of digital core pulse Gauss manufacturing process based on Impulse invariance procedure.The method overcome the deficiency that core pulse simulation Gauss is shaped, solve the digital Gaussian shaping demand of core pulse, for the digitizing of nuclear instrument is laid a good foundation.

Object of the present invention is realized by following technical scheme:

Based on the digital core pulse Gauss manufacturing process of Impulse invariance procedure, comprising:

According to the circuit of simulation Gauss formation system, obtain the differential equation of circuit system input signal and output signal, the differential equation is derived by frequency-domain analysis, obtain the unit impulse response of simulation Gaussian Systems;

The frequency response of analysis mode Gauss formation system, and frequency that simulation Gauss formation system is sampled is determined according to the spectral range of frequency response;

Simulation Gauss formation system Impulse invariance procedure is converted to numeric field by analog domain, obtains the unit impulse response of digital Gaussian formation system, containing the forming parameter that can adjust waveform widths in described impulse response;

Forming parameter in selected impulse response, and the unit impulse response of corresponding digital Gaussian formation system is determined according to selected forming parameter value;

The unit impulse response of the core pulse signal and digital Gaussian formation system that are input to digital Gaussian formation system is carried out Convolution sums computing, realizes digital core pulse Gauss and be shaped.

Compared with prior art, one or more embodiment of the present invention can have the following advantages by tool:

Effectively overcome the deficiency of simulation Gauss formation system, be shaped digital core pulse signal the Gaussian waveform that is as the criterion, and can according to needing flexible parameter value to shaping waveform in using, to meet different measurement demands, the energy resolution of raising system, in digital core energy depressive spectroscopy, the real-time implementation of Gaussian particle filter is laid a good foundation.

Other features and advantages of the present invention will be set forth in the following description, and, partly become apparent from instructions, or understand by implementing the present invention.Object of the present invention and other advantages realize by structure specifically noted in instructions, claims and accompanying drawing and obtain.

Accompanying drawing explanation

Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for instructions, with embodiments of the invention jointly for explaining the present invention, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the process flow diagram of digital Gaussian shaping implementation procedure;

Fig. 2 is the circuit theory diagrams of simulation Gauss formation system;

Fig. 3 is that Gauss corresponding to different parameters value is shaped waveform.

Embodiment

Easy understand, according to technical scheme of the present invention, do not changing under connotation of the present invention, one of ordinary skill in the art can propose multiple frame mode of the present invention and method for making.Therefore following embodiment and accompanying drawing are only illustrating of technical scheme of the present invention, and should not be considered as of the present invention all or be considered as restriction or the restriction of technical solution of the present invention.

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail.

As shown in Figure 1, be the digital core pulse Gauss manufacturing process based on Impulse invariance procedure, the method comprises the following steps:

Step 10 is according to the circuit of simulation Gauss formation system, obtain circuit system input signal f (t) and the differential equation outputing signal y (t), the differential equation is derived by frequency-domain analysis, obtains unit impulse response h (t) of simulation Gaussian Systems;

Namely the circuit of above-mentioned simulation Gauss formation system is the circuit of simulation Sallen-Key wave filter, according to the circuit theory (as shown in Figure 2) of simulation Sallen-Key wave filter, the differential equation listed between input signal f (t) and output signal y (t) is:

R ²C ²y"(t)+RCy′(t)+y(t)＝2f(t)(1)

The unit impulse response of simulation Gaussian Systems is derived with frequency domain analysis

$f\left(\mathrm{\ω}\right)={\∫}_{-\∞}^{\∞}f\left(t\right)e^{-\mathrm{j\ωt}}\mathrm{dt}---\left(2\right)$

$Y\left(\mathrm{\ω}\right)={\∫}_{-\∞}^{\∞}y\left(t\right)e^{-\mathrm{j\ωt}}\mathrm{dt}---\left(3\right)$

$\frac{d^{n}y\left(t\right)}{{\mathrm{dt}}^n}\stackrel{L}{\↔}j{\mathrm{\ω}}^{n}Y\left(\mathrm{\ω}\right)---\left(4\right)$

According to the frequency response function H (ω) that must simulate Gauss's formation system is:

$H\left(\mathrm{\ω}\right)=\frac{Y\left(\mathrm{\ω}\right)}{F\left(\mathrm{\ω}\right)}=\frac{2}{R^2{C}^2{\left(\mathrm{j\ω}\right)}^2+\mathrm{RCj\ω}+1}---\left(5\right)$

Carry out inverse Fourier transform to it to obtain:

$h\left(t\right)=\frac{{2e}^{-{\left(\frac{1}{2\mathrm{FC}}\right)}^t}\sin \left(\frac{\sqrt{B}}{2\mathrm{RC}}\right)t}{\sqrt{3}\mathrm{RC}}u\left(t\right)---\left(6\right)$

The frequency response of step 20 analysis mode Gauss formation system, and frequency that simulation Gauss formation system is sampled is determined according to the spectral range of frequency response;

Guarantee that sample frequency is greater than 2 times of simulation Gauss formation system frequency response bandwidth, when changing to numeric field to avoid analog domain, spectral aliasing occurs.

Simulation Gauss formation system is converted to numeric field by analog domain by step 30, obtains unit impulse response h (n) of digital Gaussian formation system, containing the forming parameter that can adjust waveform widths in described impulse response;

Unit impulse response h (n) of described digital Gaussian formation system just in time equals the sampled value of impulse response h (t) of analog filter, i.e. h (n)=h (t) | _t=nT, T is the sampling period.

$h\left(n\right)=\frac{{2\mathrm{ae}}^{-\frac{a}{2}n}\sin \frac{\sqrt{3}a}{2}n}{\sqrt{3}}u\left(n\right)---\left(7\right)$

Wherein, $\frac{T}{\mathrm{RC}}=a$

Step 40 selectes forming parameter suitable in impulse response, namely determines the value of RC and T, and determines unit impulse response h (n) of corresponding digital Gaussian formation system according to selected forming parameter value;

The unit impulse response of core pulse signal and digital Gaussian formation system that step 50 is input to digital Gaussian formation system carries out Convolution sums computing, realizes digital core pulse Gauss and is shaped, that is:

$y\left(n\right)=f\left(n\right)*h\left(n\right)=\underset{k=-\∞}{\overset{\∞}{\mathrm{\Σ}}}f\left(m\right)h(n-m)---\left(8\right)$

Fig. 3 is the waveform of parameter Gaussian particle filter when getting different value.As can be seen from the figure parameter value can affect width and the waveform shape of shaped pulse, can select suitable parameter value according to actual needs in practical application, to meet different measurement demands.

Although the embodiment disclosed by the present invention is as above, the embodiment that described content just adopts for the ease of understanding the present invention, and be not used to limit the present invention.Technician in any the technical field of the invention; under the prerequisite not departing from the spirit and scope disclosed by the present invention; any amendment and change can be done what implement in form and in details; but scope of patent protection of the present invention, the scope that still must define with appending claims is as the criterion.

Claims (4)

1., based on the digital core pulse Gauss manufacturing process of Impulse invariance procedure, it is characterized in that, described method comprises:

According to the circuit of simulation Gauss formation system, obtain the differential equation of circuit system input signal and output signal, the differential equation is derived by frequency-domain analysis, obtain the unit impulse response of simulation Gaussian Systems;

The frequency response of analysis mode Gauss formation system, and frequency that simulation Gauss formation system is sampled is determined according to the spectral range of frequency response;

Simulation Gauss formation system Impulse invariance procedure is converted to numeric field by analog domain, obtains the unit impulse response of digital Gaussian formation system, containing the forming parameter that can adjust waveform widths in described impulse response;

Forming parameter in selected impulse response, and the unit impulse response of corresponding digital Gaussian formation system is determined according to selected forming parameter value;

The unit impulse response of the core pulse signal and digital Gaussian formation system that are input to digital Gaussian formation system is carried out Convolution sums computing, realizes digital core pulse Gauss and be shaped.

2. the digital core pulse Gauss manufacturing process based on Impulse invariance procedure according to claim 1, is characterized in that, described frequency of sampling to simulation Gauss formation system is greater than 2 times of simulation Gauss formation system frequency response bandwidth.

3. the digital core pulse Gauss manufacturing process based on Impulse invariance procedure according to claim 1, it is characterized in that, described forming parameter affects width and the waveform shape of shaped pulse, and parameter value is less, and waveform is wider.

4. the digital core pulse Gauss manufacturing process based on Impulse invariance procedure according to claim 1, it is characterized in that, described Impulse invariance procedure is: make the unit impulse response of digital Gaussian formation system equal to simulate the sampled value of Gauss's formation system unit impulse response, thus obtain the unit impulse response of digital Gaussian formation system.