Particle detection signal polarity adaptive preprocessing circuit structure

Abstract

The utility model relates to a particle detection signal polarity self-adaptive preprocessing circuit structure, and solves the technical problems that the switching efficiency is low, the noise before and after switching is inconsistent, the operation error is easy to occur and the intelligence cannot be realized because the existing nuclear detection energy disperse spectroscopy needs to manually set an output signal of an adaptive pre-amplifier. The device comprises a positive signal processing channel, a negative signal processing channel and a signal synthesizer. The positive signal processing channel comprises two signal drivers, a signal differentiator, a positive signal selector and a positive signal limiter; the positive signal selector is only responsible for processing positive signals, and the positive signal limiter limits the positive signals; the negative signal processing channel is only responsible for processing negative signals, and the principle is similar to that of the positive signal processing channel. And the signal synthesizer synthesizes output signals of the positive signal processing channel and the negative signal processing channel into one signal and outputs the signal to the signal input end of the ADC. According to the utility model, pre-amplification signals with different polarities are processed independently and then synthesized, thereby realizing unified pre-processing operation of positive and negative signals.

Description

Technical Field

[0001] The utility model relates to a signal adaptation circuit for particle detection, in particular to a circuit structure for adaptive preprocessing of particle detection signal polarity, which is used for preprocessing the preamplifier signal input to the ADC in a nuclear detection spectrometer. Background Art

[0002] In the field of particle detection, the signals generated by particle detectors are often very weak and need to be preliminarily amplified and processed by a preamplifier (abbreviation: preamp) to provide a basis for subsequent signal processing and data analysis. The output signals of different types of preamps are also different, with differences in signal polarity, signal type, etc. Some preamps output positive signals, while some output negative signals. For example, the output signal of an RC feedback type charge preamp is a negative exponential decay signal, while the output signal of a reset type charge preamp (also called a transistor recovery type preamp) is a signal pattern of "first rising step by step and resetting when reaching the threshold". This requires the nuclear detection spectrometer located at the back end connected to the preamp to be able to adjust and transform the settings according to the differences in signal polarity or signal type, etc. of different preamps to adapt to the output signals of different preamps (abbreviation: preamp signals).

[0003] The existing transformation setting methods of nuclear detection spectrometers on the market are all in manual mode, which can be specifically divided into a hardware manual setting mode and a software manual setting mode. The hardware manual setting mode is to set switch components such as jumper switches in the hardware system of the nuclear detection spectrometer. Users can switch the jumper switches to adapt to preamp signals of different polarities. The software manual setting mode is to change the switch components in the former to mechanical switches or electronic switches that can be controlled by a program, and then set control options in the spectrometer control software. Users can switch the preamp signals that the nuclear detection spectrometer can adapt to by setting these software control options.

[0004] However, the above two manual setting modes have the following disadvantages:

[0005] (1) Switch components are added to the nuclear detection spectrometer, and each time the switch components are switched, a certain electronic balance time is required, resulting in low switching efficiency.

[0006] (2) The switch components will cause a large amount of noise in the nuclear detection spectrometer at the moment of switching, and there will still be a problem that the noise characteristics are inconsistent with those before switching after stabilization, so that the filtering parameters need to be readjusted in subsequent signal processing to adapt to the new noise characteristics.

[0007] (3) When using the two manual modes, users may fail to select the signal polarity correctly or forget to select the signal polarity due to operational errors, and then fail to obtain correct test data; sometimes users may suspect that the nuclear detection spectrometer has a malfunction, which seriously affects the user experience. Similarly, since the manual setting mode cannot adapt to the signal, it directly affects the intelligent development of the nuclear detection spectrometer.

[0008] If you choose to process the preamplifier signal uniformly, such as positive polarity processing, you can make full use of the full range of the ADC and improve the accuracy of signal digitization, but it loses the random noise of the negative polarity part and the noise suppression performance will be reduced. Utility Model Content

[0009] The purpose of the utility model is to solve the technical problems that the existing nuclear detection energy spectrometer needs to be manually set to adapt to different polarities or different types of output signals of the preamplifier, has low switching efficiency, inconsistent noise before and after switching, easy operating errors and cannot be intelligent, and to provide a particle detection signal polarity adaptive preprocessing circuit structure.

[0010] In order to achieve the above purpose, the technical solutions provided by the utility model are as follows:

[0011] A particle detection signal polarity adaptive preprocessing circuit structure is used to preprocess the preamplifier signal input to ADC in a nuclear detection spectrometer. The special features are:

[0012] It includes a positive signal processing channel, a negative signal processing channel and a signal synthesizer; the output end of the signal synthesizer is connected to the input end of the ADC; the output ends of the positive signal processing channel and the negative signal processing channel are respectively connected to the input end of the signal synthesizer;

[0013] The positive signal processing channel includes a first signal driver, a positive signal selector, a first signal differentiator, a positive signal limiter and a second signal driver which are sequentially connected along the signal transmission path;

[0014] The first signal driver performs power amplification on the preamplifier signal and outputs it to the positive signal selector; the positive signal selector selects the positive signal from the preamplifier signal after driving and outputs it to the first signal differentiator; the first signal differentiator differentiates the obtained positive signal and outputs it to the positive signal limiter; the positive signal limiter performs voltage limiting on the differentiated positive signal and outputs it to the second signal driver, and the limiting range of the positive signal limiter is N1 to +10V, N1 is the negative limiting voltage, and N1<0V; the second signal driver performs power amplification on the positive signal after limiting and outputs it to the signal synthesizer;

[0015] The negative signal processing channel includes a third signal driver, a negative signal selector, a second signal differentiator, a negative signal limiter, and a fourth signal driver connected in sequence along the signal transmission path;

[0016] The third signal driver amplifies the preamplifier signal in terms of power and outputs it to the negative signal selector; the negative signal selector selects the negative signal from the preamplifier signal after driving and outputs it to the second signal differentiator; the second signal differentiator differentiates the obtained negative signal and outputs it to the negative signal limiter; the negative signal limiter performs voltage limiting on the differentiated negative signal and outputs it to the fourth signal driver, and the limiting range of the negative signal limiter is -10V to N2, where N2 is the positive limiting voltage and N2 > 0V; the fourth signal driver amplifies the limited negative signal in terms of power and outputs it to the signal synthesizer;

[0017] The signal synthesizer synthesizes the positive signal and the negative signal into one signal and outputs it to the ADC, thereby realizing the adaptive preprocessing of preamplifier signals with different polarities.

[0018] Further, the range of the negative limiting voltage N1 is (-0.2*M)V to (-0.05*M)V, and the range of the positive limiting voltage N2 is (0.05*M)V to (0.2*M)V, where M is the reference voltage of the ADC.

[0019] Further, the negative limiting voltage N1 = (0.1*M)V, and the positive limiting voltage N2 = (0.1*M)V.

[0020] Further, the positive signal selector includes a first unidirectional conduction unit and a first baseline shifter connected in sequence along the signal transmission path, and the first unidirectional conduction unit is connected in the forward direction and is used to block the negative signal from passing through;

[0021] The negative signal selector includes a second unidirectional conduction unit and a second baseline shifter connected in sequence along the signal transmission path, and the second unidirectional conduction unit is connected in the reverse direction and is used to block the positive signal from passing through.

[0022] Further, the positive signal limiter includes a first positive clamping circuit and a first negative clamping circuit connected in sequence along the signal transmission path. The first positive clamping circuit is used to limit the differentiated positive signal below +10V, and the first negative clamping circuit limits the differentiated positive signal above the negative limiting voltage N1;

[0023] The negative signal limiter includes a second positive clamping circuit and a second negative clamping circuit connected in sequence along the signal transmission path. The second positive clamping circuit is used to limit the differentiated negative signal below the positive limiting voltage N2, and the second negative clamping circuit limits the differentiated negative signal above -10V;

[0024] Furthermore, the distortion-free input voltage ranges of the first signal driver, positive signal selector, first signal differentiator, positive signal limiter, second signal driver, third signal driver, negative signal selector, second signal differentiator, negative signal limiter, fourth signal driver, and signal synthesizer are all -10V to +10V.

[0025] Advantages of the present utility model compared with the prior art:

[0026] 1. For a particle detection signal polarity adaptive preprocessing circuit structure of the present utility model, through the design of two signal selectors and two signal limiters, the preamplifier signal is converted into positive and negative signals with unchanged absolute amplitude values according to different polarities, and is limited within a specified range. After independent separate processing and then synthesis, unified preprocessing operations for positive and negative signals are achieved, while retaining the random noise in the positive and negative polarity parts, and the noise suppression performance is good. For users, they can directly connect the signal line during use without caring about the positive and negative polarities of the signal, which is convenient and intelligent.

[0027] 2. For a particle detection signal polarity adaptive preprocessing circuit structure of the present utility model, unified preprocessing operations are performed on the preamplifier signal, achieving unified preprocessing operations for the output signals of different types of preamplifiers, that is, the nuclear detection spectrometer can automatically adapt to signals with different polarities or different types. For users, they can directly connect the signal line during use without caring about the types of preamplifiers, which is convenient and intelligent.

[0028] 3. For a particle detection signal polarity adaptive preprocessing circuit structure of the present utility model, there is no need to set a signal polarity selection item, nor do users need to worry about the signal polarity identification problem when running the software. The software development process is more concise and efficient, avoiding the problems existing in manual switching. Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of an embodiment of a particle detection signal polarity adaptive preprocessing circuit structure of the present utility model;

[0030] Figure 2 is a schematic structural diagram of the positive signal selector in the embodiment of the present utility model;

[0031] Figure 3 is a schematic structural diagram of the negative signal selector in the embodiment of the present utility model;

[0032] Figure 4 is a schematic structural diagram of the positive signal limiter in the embodiment of the present utility model. Detailed Embodiments

[0033] The following will further illustrate the specific technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present utility model.

[0034] The present utility model provides a particle detection signal polarity adaptive preprocessing circuit structure to solve the technical problem that the current particle measurement spectrometer cannot automatically adapt to the positive and negative polarities of the preamplifier signal and can only rely on the operator to manually select the signal type, thus restricting the intelligent development of the instrument.

[0035] See Figures 1 - 4 , a particle detection signal polarity adaptive preprocessing circuit structure for preprocessing the preamplifier signal input to the ADC in a nuclear detection spectrometer, including a positive signal processing channel, a negative signal processing channel, and a signal synthesizer; the output end of the signal synthesizer is connected to the input end of the ADC; the output ends of the positive signal processing channel and the negative signal processing channel are respectively connected to the input end of the signal synthesizer; the ADC is connected to a reference voltage M.

[0036] The positive signal processing channel includes a first signal driver, a positive signal selector, a first signal differentiator, a positive signal limiter, and a second signal driver connected in sequence along the signal transmission path;

[0037] The negative signal processing channel includes a third signal driver, a negative signal selector, a second signal differentiator, a negative signal limiter, and a fourth signal driver connected in sequence along the signal transmission path.

[0038] The particle detection signal is unipolar and can only be a positive signal or a negative signal. The preamplifier signal is driven by two signal drivers and enters the positive and negative signal selectors respectively. The selected signal is differentiated by the signal differentiator and then limited within a specified range by the positive and negative signal limiters. The two limited signals are respectively driven by the signal drivers and then simultaneously connected to the signal synthesizer, and finally synthesized into a target signal for output, thus completing the signal adaptive preprocessing process. Specifically:

[0039] The first signal driver amplifies the power of the preamplifier signal and outputs it to the input end of the positive signal selector; the positive signal selector selects the positive signal in the driven preamplifier signal and outputs it to the first signal differentiator; the first signal differentiator differentiates the obtained positive signal and outputs it to the positive signal limiter; the positive signal limiter limits the voltage of the differentiated positive signal and outputs it to the second signal driver. The limiting range of the positive signal limiter is N1~+10V, N1 is the negative limiting voltage, and N1 = (-0.1*M)V; the second signal driver amplifies the power of the limited positive signal and outputs it to the signal synthesizer;

[0040] The third signal driver amplifies the preamplified signal in power and outputs it to the input end of the negative signal selector; the negative signal selector selects the negative signal from the preamplified signal after driving and outputs it to the second signal differentiator; the second signal differentiator differentiates the obtained negative signal and outputs it to the negative signal limiter; the negative signal limiter limits the voltage of the differentiated negative signal and outputs it to the fourth signal driver, and the limiting range of the negative signal limiter is -10V to N2, where N2 is the positive limiting voltage and N2 = (0.1 * M)V; the fourth signal driver amplifies the limited negative signal in power and outputs it to the signal synthesizer;

[0041] The signal synthesizer synthesizes the positive signal and the negative signal into one signal and then outputs it to the ADC, so as to realize the adaptive preprocessing of the preamplified signals with different polarities respectively.

[0042] In the embodiment of the present utility model, as Figure 3 shown, the positive signal selector includes a first unidirectional conduction unit and a first baseline shifter connected in sequence along the signal transmission path. The first unidirectional conduction unit is connected in the forward direction and is used to block the negative signal; as Figure 4 shown, the negative signal selector includes a second unidirectional conduction unit and a second baseline shifter connected in sequence along the signal transmission path. The second unidirectional conduction unit is connected in the reverse direction and is used to block the positive signal.

[0043] As Figure 4 described, the positive signal limiter includes a first positive clamping circuit and a first negative clamping circuit connected in sequence along the signal transmission path. The first positive clamping circuit is used to limit the differentiated positive signal below +10V, and the first negative clamping circuit limits the differentiated positive signal above the negative limiting voltage N1; the negative signal limiter has the same structure as the positive signal limiter, including a second positive clamping circuit and a second negative clamping circuit connected in sequence along the signal transmission path. The second positive clamping circuit is used to limit the differentiated negative signal below the positive limiting voltage N2, and the second negative clamping circuit limits the differentiated negative signal above -10V.

[0044] In the embodiment of the present utility model, the distortion-free input voltage ranges of the first signal driver, the positive signal selector, the first signal differentiator, the positive signal limiter, the second signal driver, the third signal driver, the negative signal selector, the second signal differentiator, the negative signal limiter, the fourth signal driver, and the signal synthesizer are all -10V to +10V.

[0045] The assembly method of the embodiment of the present utility model is:

[0046] (0) Prepare the following electronic components: four identical signal drivers, two signal differentiators, one positive signal selector, one negative signal selector, one positive signal limiter, one negative signal limiter, and one signal synthesizer. Select an ADC with a reference voltage specification of 1.2V and set the reference voltage to 1.2V. Set the positive signal limiter to limit the signal to (-0.1×1.2)V to +10V; set the negative signal limiter to limit the signal to -10V to (0.1×1.2)V;

[0047] (1) Connect the first signal driver, positive signal selector, first signal differentiator, positive signal limiter, and second signal driver in sequence according to the signal transmission direction to form a positive signal processing channel;

[0048] (2) Connect the third signal driver, negative signal selector, second signal differentiator, negative signal limiter, and fourth signal driver in sequence according to the signal transmission direction to form a negative signal processing channel;

[0049] (3) Divide the input signal (pre-amplified signal) into two parallel paths with wires and connect them to the input terminals of the first signal driver and the third signal driver respectively;

[0050] (4) Connect the output signals of the second signal driver and the fourth signal driver to the input terminal of the signal synthesizer at the same time. The signal synthesizer outputs one signal and connects it to the ADC, and the ADC outputs a digital signal.

[0051] The working principle of the embodiment of the present utility model is as follows:

[0052] When the particle detection signal is a positive signal, it is preprocessed through the positive signal processing channel. At this time, the signal cannot pass through the negative signal channel, so the output of the negative signal processing channel is 0. The signal after the two channels pass through the signal synthesizer is the signal processed by the positive signal processing channel;

[0053] When the particle detection signal is a negative signal, it is preprocessed through the negative signal processing channel. At this time, the signal cannot pass through the positive signal channel, so the output of the positive signal processing channel is 0. The signal after the two channels pass through the signal synthesizer is the signal processed by the negative signal processing channel.

[0054] The positive or negative signal is decomposed by the signal differentiator after passing through it, and then the positive signal limiter and the negative signal limiter respectively limit the signal within the specified range to prevent serious negative overload of the signal caused by differentiation, thus affecting the amplitude value of the subsequent signal; finally, the two signals are synthesized by the signal synthesizer and then sent to the ADC to complete the digital signal conversion.

[0055] The above are only the embodiments of the present utility model, and are not limitations on the protection scope of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present utility model. For those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present utility model, and the scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A particle detection signal polarity adaptive preprocessing circuit structure, used for preprocessing the preamplifier signal input to ADC in a nuclear detection spectrometer, characterized in that: It includes a positive signal processing channel, a negative signal processing channel and a signal synthesizer; the output end of the signal synthesizer is connected to the input end of the ADC; the output ends of the positive signal processing channel and the negative signal processing channel are respectively connected to the input end of the signal synthesizer; The positive signal processing channel includes a first signal driver, a positive signal selector, a first signal differentiator, a positive signal limiter and a second signal driver which are sequentially connected along a signal transmission path; The first signal driver performs power amplification on the preamplifier signal and outputs the power amplification to the positive signal selector; The positive signal selector selects the positive signal from the driven preamplifier signal and outputs it to the first signal differentiator; The first signal differentiator differentiates the obtained positive signal and outputs it to the positive signal limiter; The positive signal limiter performs voltage limiting on the differentiated positive signal and outputs it to the second signal driver, the limiting range of the positive signal limiter is N1 to +10V, N1 is the negative limiting voltage, N1<0V; The second signal driver amplifies the power of the limited positive signal and outputs it to the signal synthesizer; The negative signal processing channel includes a third signal driver, a negative signal selector, a second signal differentiator, a negative signal limiter and a fourth signal driver which are sequentially connected along the signal transmission path; The third signal driver performs power amplification on the preamplifier signal and outputs the power amplification to the negative signal selector; The negative signal selector selects the negative signal in the driven preamplifier signal and outputs it to the second signal differentiator; The second signal differentiator differentiates the obtained negative signal and outputs it to the negative signal limiter; The negative signal limiter performs voltage limiting on the differentiated negative signal and outputs it to the fourth signal driver, the limiting range of the negative signal limiter is -10V to N2, N2 is the positive limiting voltage, N2>0V; The fourth signal driver amplifies the power of the limited negative signal and outputs it to the signal synthesizer; The signal synthesizer synthesizes the positive signal and the negative signal into one signal and outputs the signal to the ADC, thereby realizing adaptive preprocessing of preamplifier signals of different polarities.

2. The particle detection signal polarity adaptive preprocessing circuit structure according to claim 1 is characterized in that: The negative limit voltage N1 ranges from (-0.2*M)V to (-0.05*M)V, and the positive limit voltage N2 ranges from (0.05*M)V to (0.2*M)V, where M is the reference voltage of ADC.

3. The particle detection signal polarity adaptive preprocessing circuit structure according to claim 2 is characterized in that: The negative limit voltage N1 = (-0.1*M)V, and the positive limit voltage N2 = (0.1*M)V.

4. The particle detection signal polarity adaptive preprocessing circuit structure according to any one of claims 1 to 3, characterized in that: The positive signal selector comprises a first unidirectional conductive unit and a first baseline shifter connected in sequence along the signal transmission path, the first unidirectional conductive unit being connected in a positive direction for preventing the negative signal from passing through; The negative signal selector includes a second unidirectional conductive unit and a second baseline shifter connected in sequence along the signal transmission path, and the second unidirectional conductive unit is reversely connected to prevent the positive signal from passing through.

5. The particle detection signal polarity adaptive preprocessing circuit structure according to claim 4 is characterized in that: The positive signal limiter includes a first positive clamping circuit and a first negative clamping circuit connected in sequence along the signal transmission path, the first positive clamping circuit is used to limit the differentiated positive signal to below +10V, and the first negative clamping circuit limits the differentiated positive signal to above the negative limit voltage N1; The negative signal limiter includes a second positive clamping circuit and a second negative clamping circuit connected in sequence along the signal transmission path. The second positive clamping circuit is used to limit the differentiated negative signal to below the positive limit voltage N2, and the second negative clamping circuit limits the differentiated negative signal to above -10V.

6. The particle detection signal polarity adaptive preprocessing circuit structure according to claim 5, characterized in that: The undistorted input voltage range of the first signal driver, positive signal selector, first signal differentiator, positive signal limiter, second signal driver, third signal driver, negative signal selector, second signal differentiator, negative signal limiter, fourth signal driver, and signal synthesizer is -10V to +10V.

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