CN104155679B - Multi channel spectrum analysis instrument based on ADS1605 - Google Patents

Abstract

The invention discloses a multi-channel energy spectrum analyzer based on ADS1605, which includes two parts: the first part is a front-end conditioning circuit composed of a front-end amplifier circuit, a linear amplifier circuit, a filter shaping circuit and a differential conversion circuit, and the analog input signal passes through The front-end conditioning circuit signal is amplified and then differentially converted to output a differential signal; the second part is the control circuit, including the differential signal of the first part and the input signal drive of the voltage reference circuit, as well as the external clock control circuit and working state control circuit to control ADS1605 data acquisition. The present invention introduces the latest high-speed ARM7 processor into the multi-channel energy spectrum analyzer, through the front-end conditioning circuit and the control circuit, the signal differential conversion and amplification, the working state control, and the shaping of the collected signal are realized to realize the high speed and high precision of the ADS1605 16-bit 5MHZ analog-to-digital conversion.

Description

Multi-channel Energy Spectrum Analyzer Based on ADS1605

technical field

The invention belongs to the technical field of nuclear energy spectrum measurement, and relates to a multi-channel energy spectrum analyzer based on ADS1605.

Background technique

Nuclear energy spectrum measurement technology is a highly comprehensive emerging technology, which integrates multiple disciplines such as electronic technology, nuclear detection technology, and computer technology. At present, it has become one of the important means of material composition analysis, and plays an increasingly important role in medicine, geology, environmental science, chemistry, archaeology and other disciplines.

With the rapid development of nuclear electronics and computer technology, the performance of multi-channel energy spectrum analyzers has been continuously improved. Foreign nuclear spectrometers have high performance, but are expensive and difficult to be widely used by most domestic users. After several years of hard work, domestic researchers have developed multi-channel energy spectrometers constructed from early traditional analog circuits and digital circuits. So far, various types of energy spectrometers for field (on-site) use have been developed. At present, multi-channel energy spectrometers are developing toward the trend of powerful functions, stable performance, high instrument integration, easy-to-use operating environment, and low power consumption.

As a key component of the multi-channel energy spectrum analyzer, it mainly completes the following main tasks: (1) Differentially amplifies the input charge level signal and ensures that the signal is not distorted during the amplification process; (2) Forming a circuit through filtering can The input signal composed of external noise, system noise and useful signal superposition is denoised; (3) In order to preprocess the original data and obtain better measurement results, it is necessary to have a faster acquisition speed and measurement accuracy.

Contents of the invention

The purpose of the present invention is to provide a multi-channel energy spectrum analyzer based on ADS1605 that can meet the requirements of the hardware system in the nuclear energy spectrum analyzer system for data analog-to-digital conversion.

Technical scheme of the present invention:

A multi-channel energy spectrum analyzer based on ADS1605, which includes two parts, a front-end conditioning circuit and a control circuit, the front-end conditioning circuit includes a front-end amplifier circuit U1, a linear amplifier circuit U2, a filter shaping circuit U3 and a differential conversion circuit U4; the control circuit Including voltage reference circuit U5, working state control circuit U6 and clock control circuit U7; differential conversion circuit U4, voltage reference circuit U5, working state control circuit U6 and clock control circuit U7 are connected with ADS1605 analog-to-digital converter U8; the input charge signal is passed through The front-end amplifier circuit U1 is amplified at the first level, and then after the main amplification of the linear amplifier circuit U2, it is filtered by U3 and converted by U4 to form a differential input signal that is connected to pins 4 and 5 of the ADS1605 analog-to-digital converter U8; in the voltage reference circuit U5 The input voltage is passed through the precision reference voltage source chip and then the reference voltage is output through differential conversion, which is connected to the pins 60, 61, 62, 63, 64 of ADS1605 analog-to-digital converter U8, and ADS1605 analog-to-digital converter U8 converts the differentially converted input The signal is compared with the reference voltage after differential conversion to quantify the data; the external voltage input in the working state control circuit U6 is connected to the working control bit pins 13, 15, 21, 22 of the ADS1605 analog-to-digital converter U8 through the dial switch, Control the working state of the ADS1605 analog-to-digital converter U8; finally, in the clock control circuit U7, an external clock oscillator is connected to the pin 56 of the ADS1605 analog-to-digital converter U8 to provide a stable clock signal to the ADS1605 to control the data sampling of the ΔΣ modulator.

After the analog input signal is connected to the circuit, it passes through two independent amplifying circuits in series to realize the first-level amplification and second-level amplification of the signal, and then connects to the filter shaping circuit, which is output by the differential conversion circuit, and the clock signal is input through the external clock input circuit and works The control circuit hardware controls the ADS1605 chip selection bit and the read/write bit high and low levels, and adopts a differential input method to realize the parallel acquisition of 16-bit 5MHZ high-speed and high-precision signals.

The core component of the front-end amplifier circuit U1 is the LF357 operational amplifier. The analog signal input is connected to the 2nd pin of the LF357 operational amplifier through a capacitor; a capacitor and a resistor are connected in parallel and connected across the 2nd pin terminal and the 6th pin of the LF357 operational amplifier. The terminal of the output pin is connected to the input end of the linear amplifier circuit U2 via the No. 6 output of the front-end amplifier circuit U1.

In the linear amplification circuit U2, the signal output from the front-end amplification circuit U1 of the upper stage circuit is connected to the No. 2 pin of the NE5534 operational amplifier through a resistor, and a capacitor and a resistor are connected in parallel and then connected across the No. 2 pin of the NE5534 operational amplifier and Between No. 6 pins; two capacitors are connected in parallel to the positive and negative power supply pins of the NE5534 operational amplifier, and are output by No. 6 of the NE5534 operational amplifier.

In the voltage reference circuit U5, the input voltage is connected to the No. 2 pin of the REF028U reference chip through a filter circuit composed of four capacitors with different capacitances. After filtering, the signal output from the pin 6 is divided into four outputs: two of them The circuit is converted by two OPA2822U operational amplifiers U9 and U10 to form a voltage reference signal. The two circuits are connected as follows: one signal is connected to the pin 5 of the OPA2822U operational amplifier U9 through the potentiometer, and the secondary output pin of the OPA2822U operational amplifier U9 No. 7 is connected to the reference voltage negative pins 60 and 61 of the ADS1605 analog-to-digital converter U8; one signal is connected to the pin 3 of the OPA2822U operational amplifier U10 through the potentiometer, and the primary output pin No. 1 of U10 is connected to the ADS1605 module The positive pins 63 and 64 of the reference voltage of the digital converter U8; the other two connections are as follows: one signal is connected to the pin 3 of the OPA2822U operational amplifier U9, and the first-stage output pin 1 of the OPA2822U operational amplifier U9 is connected to the ADS1605 module The voltage median pin 62 of the digital converter U8, and the signal output from pin 1 is divided into two routes and connected to pin 6 of the OPA2822U operational amplifier U9 and pin 2 of the OPA2822U operational amplifier U10; the other signal is connected to the OPA2822U operational amplifier The pin 5 of the amplifier U10 is provided to the VCM of the differential conversion circuit through the secondary output pin 7 of the OPA2822U operational amplifier U10 for data quantization comparison.

In the working state control circuit U6, the four-way exclusion is connected to the working control bit pins 13, 15, 21, 22 of the ADS1605 analog-to-digital converter U8 through the DIP switch; in the external clock control circuit U7, the clock oscillator XOSM -573 pin 3 is connected to ADS1605 Analog to Digital Converter U8 pin 56.

The device is preferably: analog-to-digital converter ADS1605, front-end amplifier LF357 is provided in the front-end amplifier circuit, amplifier NE5534 is selected for the linear amplifier circuit, amplifier OPA2822U is selected for the differential conversion circuit, voltage reference chip REF028U, and external clock oscillator XOSM-573.

The multi-channel energy spectrum analyzer hardware composition based on ADS1605 of the present invention, in order to improve the acquisition speed and the stability of the analog-to-digital converter ADS1605, the input signal after the differential conversion is compared with the reference voltage after the differential conversion to perform data quantification, At the same time, the external clock inputs the clock signal and the hardware controls the working state. It also adopts 16-bit parallel acquisition mode, and the acquisition rate can reach 5MHZ, so that the present invention can realize high-speed acquisition and high-precision measurement while adapting to reducing volume and enhancing human-computer interaction ability; digital filtering algorithm is used to preprocess data, improving The data reliability of the device and the performance of the whole system are improved; at the same time, when the sampling is stopped, the power consumption of the system is reduced by starting the sleep mode.

The present invention combines the characteristics and advantages of nuclear energy spectrum analysis technology and data acquisition technology, analyzes and demonstrates the existing instruments, introduces a 16-bit 5MHZ high-speed high-precision analog-to-digital converter into a multi-channel energy spectrum analyzer for the first time, and applies independent research and development The ARM7 core board controls the collection and transmission of data, through the appropriate modification of the real-time measurement of the front-end conditioning circuit and filter circuit, the addition of ARM digital filter function, and the reasonable design of human-computer interaction software to improve system performance.

Description of drawings

Fig. 1 is a structural schematic diagram in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a front-end conditioning circuit in an embodiment of the present invention.

Fig. 3 is a schematic diagram of the control circuit in the embodiment of the present invention.

detailed description

The present invention can be specifically implemented through the technical solutions of the above invention, and will be further illustrated by the following technical experiment reports and examples. However, the scope of the present invention is not limited to the following examples.

Example 1:

A multi-channel energy spectrum analyzer based on ADS1605, which includes two parts, a front-end conditioning circuit and a control circuit, the front-end conditioning circuit includes a front-end amplifier circuit U1, a linear amplifier circuit U2, a filter shaping circuit U3 and a differential conversion circuit U4; the control circuit Including voltage reference circuit U5, working state control circuit U6 and clock control circuit U7; differential conversion circuit U4, voltage reference circuit U5, working state control circuit U6 and clock control circuit U7 are connected with ADS1605 analog-to-digital converter U8; the input charge signal is passed through The front-end amplifier circuit U1, linear amplifier circuit U2, filter shaping circuit U3 and differential conversion circuit U4 are connected to the pins 4 and 5 of the ADS1605 analog-to-digital converter U8; the input voltage in the voltage reference circuit U5 is connected to the REF028U reference chip U11, and the output The voltage is connected to the pins 60, 61, 62, 63, and 64 of the ADS1605 analog-to-digital converter U8 through two OPA2822U operational amplifiers U9 and U10; at the same time, the secondary output pin 7 of the OPA2822U operational amplifier U10 is connected to the VCM of the differential conversion circuit U4 Terminal connection; the working state control circuit U6 is connected to the four-way exclusion through the DIP switch and connected to the working control bit pins 13, 15, 21, 22 of the ADS1605 analog-to-digital converter U8 through pins 5, 6, 7, and 8, respectively. ; The clock oscillator XOSM-573 pin 3 in the external clock control circuit U7 is connected to the ADS1605 analog-to-digital converter U8 pin 56.

The core component of the front-end amplifier circuit U1 is the LF357 operational amplifier. The analog signal input is connected to the 2nd pin of the LF357 operational amplifier through a capacitor; a capacitor and a resistor are connected in parallel and connected across the 2nd pin terminal and the 6th pin of the LF357 operational amplifier. At the end of the output pin, the No. 6 output pin of the LF357 operational amplifier is connected to a capacitor and connected to the input end of the next circuit module, that is, connected in series to the input end of the linear amplifier circuit U2.

In the linear amplification circuit U2, the signal output from the front-end amplification circuit U1 of the upper stage circuit is connected to the No. 2 pin of the NE5534 operational amplifier through a resistor, and a capacitor and a resistor are connected in parallel and then connected across the No. 2 pin of the NE5534 operational amplifier and Between No. 6 pins; two capacitors are connected in parallel to the positive and negative power supply pins of the NE5534 operational amplifier, and the No. 6 output pin of the NE5534 operational amplifier is connected to the input terminal of the next-stage circuit with the capacitor.

In the voltage reference circuit U5, the input voltage passes through a filter circuit composed of four capacitors with different capacitances, and is connected to the No. 2 pin of the REF028U reference chip, and then output through pin 6 and then filtered by parallel capacitors, and then divided into four outputs; The two circuits are converted by two OPA2822U operational amplifiers U9 and U10 to form a voltage reference signal. The two circuits are connected as follows: one signal is connected to pin 5 of the OPA2822U operational amplifier U9 through a potentiometer, and the secondary output lead of the OPA2822U operational amplifier U9 is Pin 7 is connected to the reference voltage negative pins 60 and 61 of the ADS1605 analog-to-digital converter U8; one signal is connected to the pin 3 of the OPA2822U operational amplifier U10 through the potentiometer, and the primary output pin 1 of the OPA2822U operational amplifier U10 Connect to the positive pins 63 and 64 of the reference voltage of U8; the other two connections are as follows: one signal is connected to the pin 3 of the OPA2822U operational amplifier U9, The primary output pin 1 of the OPA2822U operational amplifier U9 is connected to the voltage median pin 62 of U8, and the signal output from the pin 1 is divided into two routes and connected to the pin 6 of the OPA2822U operational amplifier U9 and the pin 6 of the OPA2822U operational amplifier U10 Pin 2; the other signal is connected to pin 5 of the OPA2822U operational amplifier U10, and is connected to the VCM terminal of the differential conversion circuit U4 through the secondary output pin 7 of the OPA2822U operational amplifier U10.

Further explanation in conjunction with accompanying drawings:

In Figure 1, the input charge signal is amplified by the front-end amplifier circuit U1, and the signal input after the first-stage amplification is then amplified by the linear amplifier circuit U2, and the signal after the two-stage amplification is composed of external noise, system noise and useful signal Composed of superimposition, the signal is denoised by the filter forming circuit U3, and the processed signal is input to the differential input circuit U4 to form a differential mode signal, which is connected to the 16-bit analog-to-digital converter ADS1605U8 through the filter circuit; the voltage reference circuit U5 , the input voltage is passed through the precision reference voltage source chip, and then the reference voltage is output through differential conversion, which is connected to U8, so that ADS1605 compares the input signal after differential conversion with the reference voltage after differential conversion to quantify the data; at the same time, the working state control circuit In U6, through the external voltage input, it is connected to the working control bit of U8 through the dial switch to control the working state of U8; finally, in the external clock control circuit U7, the external clock oscillator is connected to U8 to provide a stable clock signal for ADS1605 to control ΔΣ modulation The data sampling of the device.

The front-end conditioning circuit is shown in Figure 2. The core component of the front-end amplifier circuit part is an LF357 operational amplifier, and the analog signal input is connected to the No. 2 pin of U9 through a capacitor. A capacitor and a resistor are connected in parallel and connected across pin 2 and output pin 6 of the LF357 operational amplifier. The output pin 6 of the LF357 operational amplifier is connected to the capacitor for overvoltage protection and connected to the next circuit module. The input terminal is the input terminal of the linear amplifier circuit. In the linear amplification circuit, the signal output from the front-end amplification circuit of the upper stage circuit is connected to the No. 2 pin of the NE5534 operational amplifier through a resistor, and the capacitor C4 and the resistor R3 are connected in parallel and connected across the No. 2 pin and No. 6 of the NE5534 operational amplifier. between pins. The two capacitors are connected in parallel to the positive and negative power supply pins of the NE5534 operational amplifier to filter the signal. The No. 6 output pin of the NE5534 operational amplifier is connected to the capacitor for overvoltage protection and connected to the input of the next stage circuit. end.

The control circuit is shown in Figure 3. In the voltage reference circuit U5, the input voltage passes through a filter circuit composed of four capacitors with different capacitances, and is connected to the No. 2 pin of the REF028U reference chip U11, and the stable voltage output through the pin 6 is filtered by parallel capacitors, and then divided into four circuits output. Two of them are converted by two OPA2822U operational amplifiers U9 and U10 to form a voltage reference signal. The two circuits are connected as follows: one signal is connected to pin 5 of OPA2822U operational amplifier U9 through a potentiometer, and the secondary output of OPA2822U operational amplifier U9 Pin 7 is connected to the reference voltage negative pins 60 and 61 of the ADS1605 analog-to-digital converter U8; one signal is connected to the pin 3 of the OPA2822U operational amplifier U10 through the potentiometer, and the primary output pin 1 of the OPA2822U operational amplifier U10 No. is connected to the reference voltage positive stage pins 63, 64 of U8. The other two connections are as follows: one signal is connected to pin 3 of OPA2822U operational amplifier U9, The primary output pin 1 of the OPA2822U operational amplifier U9 is connected to the voltage median pin 62 of U8, and the signal output from the pin 1 is divided into two routes and connected to the pin 6 of the OPA2822U operational amplifier U9 and the pin 6 of the OPA2822U operational amplifier U10 Pin 2; the other signal is connected to pin 5 of the OPA2822U operational amplifier U10, and is provided to the VCM of the differential conversion circuit through the secondary output pin 7 of the OPA2822U operational amplifier U10 for data quantization comparison. In the working state control circuit U6, the four-way exclusion is connected to the working control bit pins 13, 15, 21, 22 of U8 through the dip switch. In the external clock control circuit U7, the clock oscillator XOSM-573 pin 3 is connected to U8 pin 56.

This program uses the ADS1605 analog-to-digital conversion chip U8, which is a 16-bit, bipolar differential input channel, with the fastest acquisition rate of 5MSPS, low noise, low bias, low temperature drift, and low power consumption. The analog-to-digital conversion of a multi-channel energy spectrum analyzer is ideal.

Claims (5)

1. a kind of multichannel energy spectrum analyzer based on ADS1605, it comprises two parts, front-end conditioning circuit and control circuit, it is characterized in that: The front-end conditioning circuit includes a front-end amplifier circuit (U1), a linear amplifier circuit (U2), a filter shaping circuit (U3) and a differential conversion circuit (U4); The control circuit includes a voltage reference circuit (U5), a working state control circuit (U6) and a clock control circuit (U7); The differential conversion circuit (U4), the voltage reference circuit (U5), the working state control circuit (U6) and the clock control circuit (U7) are connected with the ADS1605 analog-to-digital converter (U8); The input charge signal is amplified by the front-end amplifier circuit (U1), and then amplified by the linear amplifier circuit (U2), filtered by the filter shaping circuit (U3), converted by the differential conversion circuit (U4) to form a differential input signal and connected to the ADS1605 On the pins 4 and 5 of the analog-to-digital converter (U8); after the input voltage in the voltage reference circuit (U5) passes through the precision reference voltage source chip, the output reference voltage is connected to the ADS1605 analog-to-digital converter (U8) through differential conversion Pins 60, 61, 62, 63, 64, the ADS1605 analog-to-digital converter (U8) compares the input signal after differential conversion with the reference voltage after differential conversion for data quantization; the external state control circuit (U6) The voltage input is connected to the working control bit pins 13, 15, 21, and 22 of the ADS1605 analog-to-digital converter (U8) through the dial switch to control the working state of the ADS1605 analog-to-digital converter (U8); finally, in the clock control circuit (U7) , connected to pin 56 of the ADS1605 analog-to-digital converter (U8) through an external clock oscillator to provide a stable clock signal to the ADS1605 to control the data sampling of the ΔΣ modulator. 2. The multi-channel energy spectrum analyzer based on ADS1605 according to claim 1, characterized in that: the core component of the front-end amplifier circuit (U1) is the LF357 operational amplifier (U11), and the analog signal input is connected to the LF357 operational amplifier through a capacitor The No. 2 pin of the amplifier; a capacitor and a resistor are connected in parallel and connected across the No. 2 pin terminal of the LF357 operational amplifier and the No. 6 output pin terminal, and the No. 6 output is connected to the input terminal of the linear amplifier circuit (U2) . 3. The multi-channel energy spectrum analyzer based on ADS1605 according to claim 1, characterized in that: in the linear amplifier circuit (U2), the signal output from the front-end amplifier circuit (U1) of the upper stage circuit is connected to the On the 2nd pin of the NE5534 operational amplifier (U12), a capacitor and a resistor are connected in parallel between the 2nd and 6th pins of the NE5534 operational amplifier; two capacitors are connected in parallel and then connected to the positive On the negative power supply pin, it is output by No. 6 of the NE5534 operational amplifier. 4. The multi-channel energy spectrum analyzer based on ADS1605 according to claim 1, characterized in that: in the voltage reference circuit (U5), the input voltage passes through a filter circuit composed of four capacitors with different capacitances, and is connected to REF028U On pin 2 of the reference chip, the signal output by pin 6 is divided into four outputs after filtering: two of them are converted by the first OPA2822U operational amplifier (U9) and the second OPA2822U operational amplifier (U10) to form a voltage Reference signal, the two connections are as follows: one signal is connected to the pin 5 of the first OPA2822U operational amplifier (U9) through the potentiometer, and the second output pin 7 of the first OPA2822U operational amplifier (U9) is connected to the ADS1605 modulus The reference voltage negative pins 60 and 61 of the converter (U8); one signal is connected to the pin 3 of the second OPA2822U operational amplifier (U10) through the potentiometer, and the primary output pin of the second OPA2822U operational amplifier (U10) No. 1 is connected to the reference voltage positive pins 63 and 64 of the ADS1605 analog-to-digital converter (U8); the other two connections are as follows: one signal is connected to the pin 3 of the first OPA2822U operational amplifier (U9), through the first OPA2822U The primary output pin 1 of the operational amplifier (U9) is connected to the voltage median pin 62 of the ADS1605 analog-to-digital converter (U8), and the signal output from the pin 1 is connected to the first OPA2822U operational amplifier (U9 ) pin 6 and pin 2 of the second OPA2822U operational amplifier (U10); the other signal is connected to pin 5 of the second OPA2822U operational amplifier (U10), through the secondary output of the second OPA2822U operational amplifier (U10) Pin 7 is provided to the VCM of the differential conversion circuit for data quantization comparison. 5. The multi-channel energy spectrum analyzer based on ADS1605 according to claim 1, characterized in that: in the working state control circuit (U6), the four-way exclusion is connected to the ADS1605 analog-to-digital converter through a dial switch (U8) work control bit pins 13, 15, 21, 22; in the external clock control circuit (U7), the clock oscillator XOSM-573 pin 3 is connected to the ADS1605 analog-to-digital converter (U8) pin 56.