Amplification circuit applied to explosive drug detector and detector

Abstract

The utility model provides an amplifying circuit applied to an explosive drug detector and the detector, the amplifying circuit comprises a signal input end, a first-stage amplifying circuit, a first filter circuit, a second-stage amplifying circuit, a second filter circuit and a sampling circuit, the first-stage amplifying circuit is connected with the signal input end, and the second-stage amplifying circuit is connected with the second filter circuit. The output end of the first-stage amplification circuit is connected with the input end of the first filter circuit, the input end of the second-stage amplification circuit is connected with the output end of the first filter circuit, the output end of the second-stage amplification circuit is connected with the input end of the second filter circuit, and the output end of the second filter circuit is connected with the sampling circuit. According to the amplifying circuit, small input signals are amplified in a high-magnification mode, interference signals of the amplified original signals are restrained through the second-stage amplifying circuit, the sampling circuit can obtain the needed original signals through the front filter circuit and the rear filter circuit, and signal analysis is effectively and rapidly conducted.

Description

Technical Field

[0001] This disclosure relates to the field of detection instruments, and in particular to an amplifier circuit and a detection instrument used in explosives and narcotics detectors. Background Technology

[0002] Ion mobility spectrometry (IMS) is now widely used in the rapid analysis and detection of explosives and narcotics. Its basic principle is to utilize the differences in ion mobility among different samples to achieve the separation and detection of these samples. Ions gain energy from an electric field and drift in a specific direction. During this drift, they lose energy through collisions with opposing gas molecules, resulting in a very weak captured signal. The original signal must be amplified significantly before being output to the sampling circuit.

[0003] The problem with existing amplifier circuits is that they only achieve high-magnification amplification. Many operational amplifiers can achieve high amplification through simple resistor-based proportional amplification. However, noise signals introduced into the original signal are also amplified and directly output to the sampling circuit for analysis, resulting in a large amount of noise in the signal. Complex software filtering is required to remove this noise and obtain a more ideal signal. Utility Model Content

[0004] To address at least one problem with the prior art, this disclosure provides an amplifier circuit and a detector for use in explosives and narcotics detectors.

[0005] The amplifier circuit used in the explosives and drugs detector includes a signal input terminal, a first-stage amplifier circuit, a first-stage filter circuit, a second-stage amplifier circuit, a second-stage filter circuit, and a sampling circuit. The first-stage amplifier circuit is connected to the signal input terminal, the output terminal of the first-stage amplifier circuit is connected to the input terminal of the first-stage filter circuit, the input terminal of the second-stage amplifier circuit is connected to the output terminal of the first-stage filter circuit, the output terminal of the second-stage amplifier circuit is connected to the input terminal of the second-stage filter circuit, and the output terminal of the second-stage filter circuit is connected to the sampling circuit.

[0006] In some implementations, the first-stage amplifier circuit includes a first operational amplifier U1, a resistor R1, and a resistor R2. One end of the resistor R2 is connected to the inverting input terminal of the first operational amplifier U1, and the other end is connected to the signal input terminal. One end of the resistor R1 is connected to the output terminal of the first operational amplifier U1, and the non-inverting input terminal of the first operational amplifier U1 is grounded.

[0007] In some implementations, the first filter circuit includes resistors R3 and R4 and capacitor C1. One end of resistor R3 is connected to the output of the first-stage amplifier circuit, and the other end is connected to one end of resistor R4 and capacitor C1. The other ends of resistor R4 and capacitor C1 are grounded.

[0008] In some embodiments, the second-stage amplifier circuit includes a second operational amplifier U2, capacitors C2 and C3, resistors R5, R6, R7, R8, R10, and R11. One end of resistor R10 is connected to the output of the first filter circuit, and the other end of resistor R10 is connected to one end of resistor R11 and one end of resistor R8. The other end of resistor R11 is connected to the inverting input of the second operational amplifier U2. The other end of resistor R8 is grounded. One end of resistor R7 is grounded and the other end is connected to the non-inverting input of the second operational amplifier U2. One end of capacitor C2 is grounded and the other end is connected to the non-inverting input of the second operational amplifier U2. One end of capacitor C3 is grounded and the other end is connected to the inverting input of the second operational amplifier U2. One end of resistor R5 is connected to the gain setting input of the second operational amplifier U2 and one end of resistor R6, and the other end of resistor R5 is connected to the bias voltage.

[0009] In some implementations, the second filter circuit includes a resistor R9 and a capacitor C4. One end of the resistor R9 is connected to the output of the second-stage amplifier circuit, and the other end is connected to the capacitor C4 and the sampling circuit. The other end of the capacitor C4 is grounded.

[0010] According to another aspect of the present invention, a detection instrument is provided, including the aforementioned amplification circuit.

[0011] The amplifier circuit of this invention amplifies a small input signal by a high factor, then passes the amplified original signal through a second-stage amplifier circuit to suppress interference signals. Through the two filtering circuits, the sampling circuit can obtain the required original signal and perform signal analysis effectively and quickly. Attached Figure Description

[0012] Figure 1 This is an amplifier circuit applied to an explosives and drugs detector according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0013] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0014] Please refer to Figure 1 According to one aspect of this disclosure, an amplifier circuit for use in an explosives and narcotics detector is provided. The circuit includes a signal input terminal, a first-stage amplifier circuit, a first-stage filter circuit, a second-stage amplifier circuit, a second-stage filter circuit, and a sampling circuit connected in sequence.

[0015] The first-stage amplifier circuit is connected to the signal input terminal, and its output terminal is connected to the input terminal of the first filter circuit. The input terminal of the second-stage amplifier circuit is connected to the output terminal of the first filter circuit, its output terminal is connected to the input terminal of the second filter circuit, and the output terminal of the second filter circuit is connected to the sampling circuit.

[0016] The amplifier circuit of the exemplary embodiment of this disclosure amplifies the small input signal by a high factor, and then passes the amplified original signal through a second-stage amplifier circuit to suppress interference signals. Through the two filtering circuits, the sampling circuit can obtain the required original signal and perform signal analysis effectively and quickly.

[0017] The first-stage amplifier circuit includes a first operational amplifier U1, resistors R1 and R2. One end of resistor R2 is connected to the inverting input of the first operational amplifier U1, and the other end is connected to the signal input of the amplifier circuit. One end of resistor R1 is connected to the output of the first operational amplifier U1. The non-inverting input of the first operational amplifier U1 is grounded. The first-stage amplifier circuit receives the input signal, amplifies it in the primary stage, and outputs the resulting signal to the first filter circuit.

[0018] The first filter circuit includes resistors R3 and R4, and capacitor C1. One end of resistor R3 is connected to the output of the first-stage amplifier circuit, such as the output of the first operational amplifier U1, and the other end is connected to one end of resistor R4 and capacitor C1. The other ends of resistor R4 and capacitor C1 are grounded. The first filter circuit is a low-pass filter circuit used to filter out high-frequency interference signals.

[0019] The second-stage amplifier circuit includes a second operational amplifier U2, capacitors C2 and C3, and resistors R5, R6, R7, R8, R10, and R11. One end of resistor R10 is connected to the output of the first filter circuit, i.e., connected to resistors R3, R4, and capacitor C1. The other end of resistor R10 is connected to one end of resistor R11 and one end of resistor R8. The other end of resistor R11 is connected to the inverting input of the second operational amplifier U2, and the other end of resistor R8 is grounded. One end of resistor R7 is grounded, and the other end is connected to the non-inverting input of the second operational amplifier U2. One end of capacitor C2 is grounded, and the other end is connected to the non-inverting input of the second operational amplifier U2. One end of capacitor C2 is grounded, and the other end is connected to the inverting input of the second operational amplifier U2. One end of resistor R5 is connected to the gain setting input of the second operational amplifier U2 and one end of resistor R6, and the other end of resistor R5 is connected to the bias voltage. The other end of resistor R6 is connected to the output of the second operational amplifier U2. The second-stage amplifier circuit mainly utilizes an instrumentation amplifier, which is used in circuits that require very high precision and stability. The instrumentation amplifier has very low DC offset, low drift, low noise, very high open-loop gain, very high common-mode rejection ratio, and high input impedance.

[0020] The second filter circuit includes resistor R9 and capacitor C4. One end of resistor R9 is connected to the output of the second-stage amplifier circuit, i.e., the output of the second operational amplifier U2, and the other end is connected to capacitor C4 and the sampling circuit. The other end of capacitor C4 is grounded. The second filter circuit is a low-pass filter circuit, used to filter out high-frequency interference signals and output the signal to the sampling circuit for signal analysis.

[0021] According to another aspect of this disclosure, a detector including the aforementioned amplification circuit is provided.

[0022] The above descriptions are merely some embodiments of this utility model. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this utility model, and all such modifications and improvements fall within the protection scope of this utility model.

Claims

1. An amplifier circuit applied to an explosive and drug detector, characterized in that, The amplification circuit comprises a signal input end, a first-stage amplification circuit, a first filter circuit, a second-stage amplification circuit, a second filter circuit and a sampling circuit, the first-stage amplification circuit is connected with the signal input end, the output end of the first-stage amplification circuit is connected with the input end of the first filter circuit, the input end of the second-stage amplification circuit is connected with the output end of the first filter circuit, the output end of the second-stage amplification circuit is connected with the input end of the second filter circuit, and the output end of the second filter circuit is connected with the sampling circuit.

2. The amplifier circuit applied to the explosive and drug detector according to claim 1, wherein, The first-stage amplification circuit comprises a first operational amplifier U1, a resistor R1 and a resistor R2, one end of the resistor R2 is connected with the inverting input end of the first operational amplifier U1, the other end of the resistor R2 is connected with the signal input end, one end of the resistor R1 is connected with the output end of the first operational amplifier U1, and the non-inverting input end of the first operational amplifier U1 is grounded.

3. The amplifier circuit applied to the explosive and drug detector according to claim 1, characterized in that, The first filter circuit comprises a resistor R3, a resistor R4 and a capacitor C1, one end of the resistor R3 is connected with the output end of the first-stage amplification circuit, the other end of the resistor R3 is connected with one end of the resistor R4 and one end of the capacitor C1, and the other end of the resistor R4 and the capacitor C1 is grounded.

4. The amplifier circuit applied to the explosive and drug detector according to claim 1, wherein, The second-stage amplification circuit comprises a second operational amplifier U2, a capacitor C2, a capacitor C3, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R10 and a resistor R11, one end of the resistor R10 is connected with the output end of the first filter circuit, the other end of the resistor R10 is respectively connected with one end of the resistor R11 and one end of the resistor R8, the other end of the resistor R11 is connected with the inverting input end of the second operational amplifier U2, the other end of the resistor R8 is grounded, one end of the resistor R7 is grounded, the other end of the resistor R7 is connected with the non-inverting input of the second operational amplifier U2, one end of the capacitor C2 is grounded, the other end of the capacitor C2 is connected with the non-inverting input end of the second operational amplifier U2, one end of the capacitor C3 is grounded, the other end of the capacitor C3 is connected with the inverting input end of the second operational amplifier U2, one end of the resistor R5 is connected with the gain setting input end of the second operational amplifier U2 and one end of the resistor R6, and the other end of the resistor R5 is connected with a bias voltage.

5. The amplifier circuit for use in an explosive or drug detector according to claim 1, wherein The second filter circuit comprises a resistor R9 and a capacitor C4, one end of the resistor R9 is connected with the output end of the second-stage amplification circuit, the other end of the resistor R9 is connected with the capacitor C4 and the sampling circuit, and the other end of the capacitor C4 is grounded.

6. A detector characterized by The amplification circuit comprises the amplification circuit according to any one of claims 1-5.

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