Alternating current electromagnetic field signal gain self-adaptive adjusting system based on operational amplifier

Abstract

The invention discloses an alternating current electromagnetic field signal gain self-adaptive adjusting system based on an operational amplifier, which comprises the operational amplifier, a programmable digital potentiometer, an interface circuit and a single chip microcomputer minimum system, a control object is the proportional transformation gain of the operational amplifier part, and the four parts are positioned on the same circuit board. After an external signal is transmitted into the system through an interface circuit, the external signal is processed by a bias amplification circuit composed of an operational amplifier, a programmable digital potentiometer and an auxiliary resistor capacitor and then is transmitted to a single-chip microcomputer minimum system, the resistance value distribution of the programmable digital potentiometer is controlled by judging the value of the output signal, and the output signal is transmitted to the single-chip microcomputer minimum system. Therefore, the gain of the bias amplification circuit is changed, and automatic gain adjustment is realized.

Description

Technical Field

[0001] The invention relates to the field of information detection of special equipment, and in particular to an adaptive adjustment system for AC electromagnetic field signal gain based on an operational amplifier. Background Art

[0002] When special equipment is inspected, it is necessary to detect the material or thickness of the corresponding equipment or workpiece. The inspection can be carried out through an electromagnetic detector. When the electromagnetic detector detects the AC electromagnetic signal of the workpiece, most of the current similar products still use manual gain adjustment. When the material and thickness of the workpiece to be tested change, the actual signal value will change, and thus cannot effectively reflect the defect characteristics. In response to the above problems, a signal gain adaptive adjustment circuit including an operational amplifier, a programmable digital potentiometer, an interface circuit, and a single-chip microcomputer system is designed. The input signal is transmitted through the interface circuit, and then processed by the bias amplifier circuit composed of an operational amplifier, a programmable digital potentiometer, and an attached resistor and capacitor. The output signal is transmitted. By judging the value of the output signal, the resistance distribution of the programmable digital potentiometer is controlled, and then the gain of the bias amplifier circuit is changed, and the purpose of automatic gain adjustment has been achieved. Summary of the invention

[0003] The purpose of the present invention is to provide a Dynalu device for adaptively adjusting the gain of an AC electromagnetic field signal, so as to realize automatic gain adjustment of an amplifier circuit.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: A dyno device for adaptively adjusting the gain of an alternating current electromagnetic field signal comprises: a PCB circuit board, the circuit board is provided with mounting holes and is fixed through the mounting holes; an operational amplifier welded on the PCB circuit board; a programmable digital potentiometer welded on the PCB circuit board; an interface circuit welded on the PCB circuit board; and a single-chip computer system connected to the PCB circuit board.

[0005] Preferably, it also includes auxiliary resistors and capacitors, an operational amplifier, a programmable digital potentiometer and auxiliary resistors and capacitors to form a bias amplifier circuit, and the AC electromagnetic field signal to be detected is transmitted from the interface circuit to the signal collector in the Denolu device, and then enters the bias amplifier circuit.

[0006] Preferably, the AC electromagnetic field signal is analyzed by the bias amplifier circuit and then transmitted to the single-chip microcomputer system. The single-chip microcomputer system controls the resistance distribution of the programmable digital potentiometer by judging the value of the output signal, thereby changing the gain of the bias amplifier circuit.

[0007] Another object of the present invention is to provide a method for adaptively adjusting the gain of a signal preprocessing stage of an AC electromagnetic field detection device.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: A method for adaptively adjusting the gain of a signal preprocessing stage of an AC electromagnetic field detection device, using the above-mentioned Dinoru device, specifically comprises the following steps: S1. Turn on the power switch, and the device starts running the entire algorithm process after powering on; S2, the external AC electromagnetic field signal is transmitted through the interface circuit to the amplifier circuit composed of the operational amplifier, programmable digital potentiometer and auxiliary resistors and capacitors; S3, the single-chip microcomputer system receives the signal modulated by the amplifier circuit composed of the operational amplifier and the programmable digital potentiometer through the PCB circuit board wiring, and converts the analog signal into a digital signal; S4. In the single-chip microcomputer system, the single-chip microcomputer processes the converted digital signal and records the value of the incoming data obtained by the single-chip microcomputer system as , the expected value is recorded as ; The current resistance of the programmable potentiometer is recorded as , the initial resistance is recorded as ; The current gain of the operational amplifier is recorded as , the initial resistance is recorded as ; S5. According to the possible interference signals, the main control microcontroller circuit part in the circuit board of this device performs corresponding digital filtering on the data, mainly filtering out the possible fluctuation interference signals, adopting the sliding average filtering algorithm to realize the real-time processing of the data, and outputting the partial filtering; the input-output relationship of the partial filtering function in the sliding average filtering algorithm is: ; in, is the latest data output after filtering, is the filtered data at the previous moment, is the filter length; For the latest original data, For the front The original data of the filter at each moment; , after the incoming data is filtered, it is recorded as ; S6. Calculate the corresponding deviation value according to the numerical sequence after filtering output: ; According to the above formula, calculate the difference between the current data and the expected data, recorded as ; S7, based on the difference between the incoming data and the expected data size Determine the resistance of the potentiometer: ;in is the proportionality factor determined empirically; S8. When the resistance of the programmable potentiometer changes, the circuit gain of the operational amplifier part Will change accordingly, and the relationship is as follows: ;in is the inherent gain ratio, which is an inherent parameter of the operational amplifier circuit part; S9. After going through the above steps, the incoming data obtained by the single-chip microcomputer system will change in value due to the change in gain. This cycle can be repeated to achieve real-time dynamic adjustment.

[0009] The beneficial effects of the present invention are as follows: the present invention relates to the field of special detection, and is used for adaptive adjustment of the gain in the signal preprocessing stage of AC electromagnetic field detection equipment. The control method in this patent mainly relies on the judgment and calculation of the signal amplitude to determine the resistance value of the digital potentiometer, and then controls the change of the gain of the operational amplifier circuit, which can realize the dynamic adjustment of the gain in the process of AC electromagnetic field signal detection, and prevent data overflow from causing measurement problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of a Denolu device for adaptively adjusting the gain of an AC electromagnetic field signal.

[0011] Figure 2 It is a schematic diagram of a method for adaptively adjusting gain in the signal preprocessing stage of AC electromagnetic field detection equipment. DETAILED DESCRIPTION

[0012] The following describes in detail the implementation mode of the present invention in a step-by-step manner. The description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0013] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only used to describe the present invention and simplify the description, rather than indicating or implying that the device or element referred to must have a specific direction, and a specific direction structure and operation, and therefore cannot be understood as a limitation on the present invention.

[0014] Embodiment 1: A Dynuru device for adaptively adjusting the gain of an AC electromagnetic field signal, comprising: a PCB circuit board, the circuit board being provided with mounting holes and being fixed through the mounting holes; an operational amplifier welded on the PCB circuit board; a programmable digital potentiometer welded on the PCB circuit board; an interface circuit welded on the PCB circuit board; and a single-chip microcomputer system connected to the PCB circuit board.

[0015] The Denolu device also includes a bias amplifier circuit composed of auxiliary resistors and capacitors, an operational amplifier, a programmable digital potentiometer and auxiliary resistors and capacitors. The AC electromagnetic field signal to be detected is transmitted from the interface circuit to the signal collector in the Denolu device and then enters the bias amplifier circuit.

[0016] The AC electromagnetic field signal is analyzed by the bias amplifier circuit and then transmitted to the single-chip microcomputer system. The single-chip microcomputer system controls the resistance distribution of the programmable digital potentiometer by judging the value of the output signal, thereby changing the gain of the bias amplifier circuit.

[0017] Embodiment 2: A method for adaptively adjusting the gain of a signal preprocessing stage of an AC electromagnetic field detection device, using the above-mentioned Dinoru device, specifically comprising the following steps: S1. Turn on the power switch, and the device starts running the entire algorithm process after powering on; S2. The external AC electromagnetic field signal is transmitted to the amplifier circuit composed of the operational amplifier, programmable digital potentiometer and auxiliary resistors and capacitors through the interface circuit; S3. The single-chip microcomputer system receives the signal modulated by the amplifier circuit composed of the operational amplifier and the programmable digital potentiometer through the PCB circuit board routing, and converts the analog signal into a digital signal; S4. In the single-chip microcomputer system, the single-chip microcomputer processes the converted digital signal and records the value of the incoming data obtained by the single-chip microcomputer system as , the expected value is recorded as ; The current resistance of the programmable potentiometer is recorded as , the initial resistance is recorded as ; The current gain of the operational amplifier is recorded as , the initial resistance is recorded as ; S5. According to the possible interference signal, the main control microcontroller circuit part in the circuit board of this device performs corresponding digital filtering on the data, mainly filtering out the possible fluctuation interference signal, using the sliding average filtering algorithm to realize real-time processing of the data, and outputting this part of the filtering; S6. Calculate the corresponding deviation value according to the numerical sequence after the filtering output: ; According to the above formula, calculate the difference between the current data and the expected data, recorded as ; S7, based on the difference between the incoming data and the expected data size Determine the resistance of the potentiometer: ;in is the proportional coefficient determined by experience; S8, when the resistance of the programmable potentiometer changes, the circuit gain of the operational amplifier part Will change accordingly, and the relationship is as follows: ;in is the inherent gain ratio, which is an inherent parameter of the operational amplifier circuit; S9. After passing through the above links, the incoming data obtained by the single-chip microcomputer system will change in value due to the gain change. This cycle can be repeated to achieve real-time dynamic adjustment.

[0018] Embodiment 3: According to the possible interference signal, the main control microcontroller circuit part in the circuit board of this device performs corresponding digital filtering on the data, mainly filtering out the possible fluctuation interference signal, adopts the sliding average filtering algorithm to realize the real-time processing of the data, and outputs the partial filtering; the input-output relationship of the partial filtering function in the sliding average filtering algorithm is: ; in, is the latest data output after filtering, is the filtered data at the previous moment, is the filter length; For the latest original data, For the front The original data of the filter at each moment, , after the incoming data is filtered, it is recorded as .

[0019] Embodiment 4: In this embodiment, a detection device is provided, in which an operational amplifier, a programmable digital potentiometer, an interface circuit, and a single-chip minimum system are provided. These four parts are located on the same circuit board, and the external signal is transmitted into the system by the interface circuit. After being processed by the bias amplifier circuit composed of the operational amplifier, the programmable digital potentiometer, and the attached resistors and capacitors, the signal is transmitted to the single-chip minimum system. By judging the value of the output signal, the resistance distribution of the programmable digital potentiometer is controlled, and then the gain of the bias amplifier circuit is changed, so as to achieve the purpose of automatic gain adjustment.

[0020] In this system, the control method mainly relies on the judgment and calculation of the signal amplitude to determine the resistance value of the digital potentiometer, and then control the change of the gain of the operational amplifier circuit. The value of the incoming data obtained by the single-chip minimum system is recorded as , the expected value is recorded as ; The current resistance of the programmable potentiometer is recorded as , the initial resistance is recorded as ; The current gain of the operational amplifier is recorded as , the initial resistance is recorded as .

[0021] According to the possible interference signals, the main control microcontroller circuit part in the main control circuit board of this device performs corresponding digital filtering on the data, mainly filtering out the possible fluctuation interference signals, and adopts the sliding average filtering algorithm to realize the real-time processing of the data. The input and output relationship of this part of the filtering function is: ;in is the latest data output after filtering, is the filtered data at the previous moment, is the filter length, For the latest original data, For the front The original data of the filter at each moment, , after the incoming data is filtered, it is recorded as .

[0022] Then, the corresponding deviation value is calculated according to the numerical sequence after filtering output: ; According to the above formula, calculate the difference between the current data and the expected data, recorded as . Then, based on the difference between the incoming data and the expected data size Determine the resistance of the potentiometer: ;in is the proportional coefficient determined empirically and is a constant. When the resistance of the programmable potentiometer changes, the circuit gain of the operational amplifier part The corresponding changes are changed, and the relationship is as follows: ;in is the inherent gain ratio, and is a constant inherent to the operational amplifier circuit part.

[0023] After going through the above three steps, the incoming data obtained by the single-chip microcomputer minimum system will change in value due to the change in gain. By repeating this cycle, real-time dynamic adjustment can be achieved.

[0024] Embodiment 5, when performing specific data analysis and calculation, the data analyzed and calculated are as follows: step A1, external signal source data is transmitted to the interface circuit; step A2, the interface circuit transmits the external signal data to the operational amplifier circuit; step A3, the operational amplifier circuit processes the signal and transmits it to the minimum system part of the single-chip microcomputer; step A4, the algorithm is executed in the minimum system part of the single-chip microcomputer, and the expected value after the algorithm is executed is 1000 LSB, and the unit LSB is the resolution unit of ADC analog-to-digital conversion.

[0025] According to the above steps, when the specific calculation is performed, the calculated values ​​are shown in the table. The interface circuit introduces the external signal data, and the numerical sequence of the signal data is shown in Table 1 below: Table 1 The numerical sequence of the analog-to-digital conversion of the external data input by the single-chip minimum system .

[0026] After the signal data in Table 1 is calculated by sliding average filtering, the numerical sequence is shown in Table 2 below: Table 2 The numerical sequence of the data in Table 1 after filtering .

[0027] After calculating the corresponding deviation, the data are shown in Table 3 below: Table 3 The numerical sequence after calculating the deviation between the data sequence in Table 2 and the expected numerical sequence .

[0028] The data after calculating the corresponding corrected digital potentiometer resistance value is shown in Table 4 below: Table 4 The resistance sequence of the digital potentiometer to be adjusted after the algorithm calculation .

[0029] The data after calculating the corresponding corrected amplifier circuit gain is shown in Table 5 below: Table 5 Gain multiples of the amplifier circuit after adjusting the digital potentiometer resistance .

[0030] The data after obtaining the corrected collected values ​​are shown in Table 6 below: Table 6 The numerical sequence of the analog-to-digital conversion of the external data after the adjustment of the single-chip minimum system .

[0031] In Table 1, Table 2, Table 3 and Table 6 above, the unit LSB is the resolution unit of ADC analog-to-digital conversion; according to the above steps, the initial resistance value of the digital potentiometer is , initial gain The data value collected is less than the expected value.

Claims

1. A Dynalu device for adaptively adjusting the gain of an AC electromagnetic field signal, characterized in that: include: PCB circuit board, the circuit board is provided with mounting holes, and is fixed through the mounting holes; the operational amplifier is welded on the PCB circuit board; the programmable digital potentiometer is welded on the PCB circuit board; the interface circuit is welded on the PCB circuit board; the single-chip computer system is connected to the PCB circuit board.

2. A Dynalu device for adaptively adjusting the gain of an AC electromagnetic field signal according to claim 1, characterized in that: It also includes auxiliary resistors and capacitors, an operational amplifier, a programmable digital potentiometer and auxiliary resistors and capacitors to form a bias amplifier circuit. The AC electromagnetic field signal to be detected is transmitted from the interface circuit to the signal collector in the Denolu device, and then enters the bias amplifier circuit.

3. A Dynalu device for adaptively adjusting the gain of an AC electromagnetic field signal according to claim 1, characterized in that: The AC electromagnetic field signal is analyzed by the bias amplifier circuit and then transmitted to the single-chip microcomputer system. The single-chip microcomputer system controls the resistance distribution of the programmable digital potentiometer by judging the value of the output signal, thereby changing the gain of the bias amplifier circuit.

4. A method for adaptively adjusting the gain of a signal preprocessing stage of an AC electromagnetic field detection device, characterized in that: The Dynuru device for adaptively adjusting the gain of an AC electromagnetic field signal according to any one of claims 1 to 3 comprises the following steps: S1. Turn on the power switch, and the device starts running the entire algorithm process after powering on; S2, the external AC electromagnetic field signal is transmitted through the interface circuit to the amplifier circuit composed of the operational amplifier, programmable digital potentiometer and auxiliary resistors and capacitors; S3, the single-chip microcomputer system receives the signal modulated by the amplifier circuit composed of the operational amplifier and the programmable digital potentiometer through the PCB circuit board wiring, and converts the analog signal into a digital signal; S4. In the single-chip microcomputer system, the single-chip microcomputer processes the converted digital signal and records the value of the incoming data obtained by the single-chip microcomputer system as , the expected value is recorded as ; The current resistance of the programmable potentiometer is recorded as , the initial resistance is recorded as ; The current gain of the operational amplifier is recorded as , the initial resistance is recorded as ; S5. According to the possible interference signal, the main control microcontroller circuit part in the circuit board of the device performs corresponding digital filtering on the data, mainly filtering out the possible fluctuation interference signal, using the sliding average filtering algorithm to realize real-time data processing, and outputting the filtering part; The input-output relationship of some filter functions in the sliding average filter algorithm is: ； in, is the latest data output after filtering, is the filtered data at the previous moment, is the filter length; For the latest original data, For the front The original data of the filter at each moment; , after the incoming data is filtered, it is recorded as ; S6. Calculate the corresponding deviation value according to the data sequence after filtering output: ； According to the above formula, the difference between the current data and the expected data is calculated and recorded as ; S7, based on the difference between the incoming data and the expected data size Determine the resistance of the potentiometer: ； in is the proportionality factor determined empirically; S8. When the resistance of the programmable potentiometer changes, the circuit gain of the operational amplifier part Will change accordingly, and the relationship is as follows: ； in is the inherent gain ratio, which is an inherent parameter of the operational amplifier circuit part; S9. After going through the above steps, the incoming data obtained by the single-chip microcomputer system will change in value due to the change in gain. This cycle can be repeated to achieve real-time dynamic adjustment.

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