Radio frequency detection circuit system

Abstract

The invention provides a radio frequency detection circuit system, and relates to the technical field of scientific instruments. The radio frequency detection circuit system comprises a radio frequency signal RF +, a radio frequency signal RF-and a full-wave detection circuit, the radio frequency signal RF + is connected with the full-wave detection circuit, and two output ends of the full-wave detection circuit are respectively connected with an upper half-cycle filter circuit and a lower half-cycle filter circuit. The rear ends of the output circuits of the upper half-cycle filter circuit and the lower half-cycle filter circuit are respectively connected with compensation and amplification circuits, and the output circuits of the two compensation and amplification circuits are connected with the subtraction circuit. The radio frequency detection circuit system can detect the change of radio frequency power with high precision so as to adjust the power supply output in time, ensure the analysis accuracy of a mass spectrometer, detect the change of radio frequency signals in a short time, feed back the change to a control system, rapidly adjust and maintain stable radio frequency power supply output, avoid the influence of external interference on the detection result, and improve the detection accuracy of the mass spectrometer. Accurate and reliable detection signals are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of scientific instruments, in particular to a radio frequency detection circuit system. BACKGROUND

[0002] A mass spectrometer is a precision instrument used to analyze the composition and structure of substances. Its core principle is to determine the mass of molecules or atoms in a sample by measuring the mass-to-charge ratio (m / z) of ions, and then deduce the composition and structure of the substance. It has been widely used in many fields such as chemistry, biology, medicine, environmental science, and material science, such as drug research and development, food safety testing, and pollutant analysis.

[0003] After the sample to be measured enters the mass spectrometer, it is ionized into ions in the ion source. After acceleration, the ions enter the mass analyzer, where they are separated due to different trajectories in the electric and magnetic fields. The separated ions reach the detector one by one, which converts the ion signal into an electrical signal and records it, forming a mass spectrum. Through analysis of the mass spectrum, information about the composition and structure of the sample can be obtained.

[0004] The mass spectrometer needs to accurately measure the mass-to-charge ratio and other parameters of the ions, which requires the output power of the radio frequency power supply to be stable and accurately controllable. The detection circuit must be able to accurately detect the change in radio frequency amplitude in order to adjust the power supply output in a timely manner, ensuring the accuracy of the mass spectrometer analysis. However, current mass spectrometers have low control accuracy and weak anti-interference ability. SUMMARY

[0005] (I) Technical problems solved

[0006] To solve the problems of low control accuracy and weak anti-interference ability, the present application provides a radio frequency detection circuit system.

[0007] (II) Technical solutions

[0008] To achieve the above purpose, the present application realizes the following technical solutions: a radio frequency detection circuit system, comprising a radio frequency signal RF+, a radio frequency signal RF-, and a full-wave detection circuit, the radio frequency signal RF+ is connected with the full-wave detection circuit, the two output ends of the full-wave detection circuit are connected with an upper half-cycle filter circuit and a lower half-cycle filter circuit respectively, the output circuit rear ends of the upper half-cycle filter circuit and the lower half-cycle filter circuit are connected with a compensation and amplification circuit respectively, and the output circuits of the two compensation and amplification circuits are connected with a subtraction circuit.

[0009] The circuit principle of the back end connection of the RF signal RF- is the same as that of the back end connection of the RF signal RF+. The two subtraction circuits at the end of the circuits of the RF signal RF+ and the RF signal RF- are both connected to the input terminal of the (A+B) / 2 circuit. The output circuit of the subtraction circuit is connected to the input terminal of the (A+B) / 2 circuit, and the RF amplitude feedback is output through the (A+B) / 2 circuit.

[0010] Preferably, the radio frequency signal RF+ and radio frequency signal RF- are V1 and V'1, and V1 and V'1 are 1MHz sine signals with equal amplitude and 180° phase difference.

[0011] Preferably, the full-wave detector circuit includes: C1, C2, C3, C4, C5, R1, R2, R3, D1, D2, and U1.

[0012] Preferably, the filter circuit includes: T1, C6, and C7.

[0013] Preferably, in the upper half-cycle filter circuit and its downstream compensation and amplification circuit, VCC, R4, D3, and C8 constitute a positive voltage diode voltage drop compensation circuit.

[0014] Preferably, in the lower half-cycle filter circuit and its downstream compensation and amplification circuit, VDD, R5, D4, and C9 constitute a negative voltage diode voltage drop compensation circuit.

[0015] Preferably, in the compensation and amplification circuit, VCC, VDD, R8, R9, R13, R14, R17, and R17 form a dual-power supply resistor network for circuit compensation.

[0016] Preferably, in the compensation and amplification circuit, R6, R19, R15, and U2 form an inverting amplifier circuit to amplify the lower half-cycle amplitude detection voltage value, with an amplification factor of -R19 / R6; R10, R20, R18, and U3 form an inverting amplifier circuit to amplify the upper half-cycle amplitude detection, with an amplification factor of -R20 / R10.

[0017] Preferably, the subtraction circuit includes: R21, R22, R23, R24, and U4, where the resistance values ​​of R21, R22, R23, and R24 are equal, and the output value of U4 = the output value of U3 - the output value of U2.

[0018] Preferably, the (A+B) / 2 circuit includes R25, R26, and U5, where the output value of U5 = (output value of U4 + output value of U'4) / 2.

[0019] (III) Beneficial Effects

[0020] This invention provides a radio frequency detection circuit system. It has the following advantages:

[0021] 1. This radio frequency detection circuit system can detect changes in radio frequency power with high precision so as to adjust the power output in a timely manner and ensure the analytical accuracy of the mass spectrometer.

[0022] 2. This radio frequency detection circuit system can detect changes in radio frequency signals in a short time, feed them back to the control system, and quickly adjust to maintain a stable radio frequency power output.

[0023] 3. This radio frequency detection circuit system avoids the influence of external interference on the detection results, ensuring that the detection signal is accurate and reliable. Attached Figure Description

[0024] Fig. 1 This is a schematic diagram of an RF detection circuit system.

[0025] Fig. 2 This is a circuit diagram of a radio frequency detection circuit system. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Please see Figs. 1-2 This invention provides a technical solution: a radio frequency (RF) detection circuit system, including an RF signal RF+, an RF signal RF-, and a full-wave detection circuit. The RF signals RF+ and RF- are 1MHz sinusoidal signals with equal amplitude and 180° phase difference obtained by transformering from an RF coil, and are superimposed with a ±500V DC signal. The full-wave detection circuit adopts a precision operational amplifier peak detection circuit. The RF signal RF+ is connected to the full-wave detection circuit. The two output terminals of the full-wave detection circuit are respectively connected to an upper half-cycle filter circuit and a lower half-cycle filter circuit. The upper half-cycle filter circuit and the lower half-cycle filter circuit respectively filter and sample the voltage of the peak detection circuit and pass it to the subsequent circuit for further processing. The output circuits of the upper half-cycle filter circuit and the lower half-cycle filter circuit are respectively connected to compensation and amplification circuits. The compensation and amplification circuits compensate and calibrate for the voltage drop of the diode detector tube and the circuit loss introduced in the previous stage. The output circuits of the two compensation and amplification circuits are connected to a subtraction circuit. The subtraction circuit subtracts the results obtained by the upper half-cycle filter sampling circuit and the lower half-cycle filter sampling circuit.

[0028] The circuit principle of the RF- back-end connection is the same as that of the RF+ back-end connection. Both subtraction circuits at the ends of the RF+ and RF- circuits are connected to the input of the (A+B) / 2 circuit. The output circuit of the subtraction circuit is connected to the input of the (A+B) / 2 circuit, providing RF amplitude feedback. The (A+B) / 2 circuit averages the voltage values ​​obtained after the sinusoidal signals with equal amplitudes and a 180° phase difference have passed through detection and compensation circuits. This ensures that both sinusoidal signals with equal amplitudes and a 180° phase difference are functioning normally.

[0029] In this embodiment, the radio frequency signal RF+ and radio frequency signal RF- are V1 and V'1, respectively. V1 and V'1 are 1MHz sine signals with equal amplitude and 180° phase difference.

[0030] The radio frequency (RF) signals RF+ and RF- are 1MHz sine waves with equal amplitude and 180° phase difference, obtained by transformering from an RF coil, and superimposed with a ±500V DC signal.

[0031] In this embodiment, the full-wave detector circuit includes: C1, C2, C3, C4, C5, R1, R2, R3, D1, D2, and U1.

[0032] The U1 and U'1 models are AD847, a high-speed, low-power single-chip operational amplifier with both ±5V and ±15V rated operating voltages, conforming to MIL-STD-883B standards. This operational amplifier features a unity-gain bandwidth of 50MHz, a slew rate of 300V / μs, and a supply current of only 5.3mA. Its DC characteristics include a 0.5mV input offset voltage, 3500V / V open-loop gain (500Ω load), a minimum common-mode rejection of 78dB, and the ability to drive a 150Ω load.

[0033] In this embodiment, the filter circuit includes: T1, C6, and C7.

[0034] The full-wave detection circuit uses a precision operational amplifier peak detection circuit. T1 and T'1 are model DA103C, which is a digital audio data transmission transformer with good insulation performance and high withstand voltage capability. The turns ratio is 1:1. This transformer can also work stably in harsh electromagnetic environments, ensuring the integrity and reliability of signal transmission.

[0035] In this embodiment, VCC, R4, D3, and C8 constitute a positive voltage diode voltage drop compensation circuit in the upper half-cycle filter circuit and its downstream compensation and amplification circuit.

[0036] The specific model of D1 / D2, D'1 / D'2, D3, D4, D'3, and D'4 is HSMS-2812, which is an RF Schottky barrier diode with a junction capacitance of 1.2pF, a voltage drop of 410mV, and a maximum forward current of 1mA.

[0037] In this embodiment, in the lower half-cycle filter circuit and its downstream compensation and amplification circuit, VDD, R5, D4, and C9 constitute a negative voltage diode voltage drop compensation circuit.

[0038] In this embodiment, the compensation and amplification circuit, VCC, VDD, R8, R9, R13, R14, R17, and R17 form a dual-supply resistor network for circuit compensation.

[0039] In this embodiment, the compensation and amplification circuit, R6, R19, R15, and U2 form an inverting amplifier circuit to amplify the lower half-cycle amplitude detection voltage value, with an amplification factor of -R19 / R6; R10, R20, R18, and U3 form an inverting amplifier circuit to amplify the upper half-cycle amplitude detection, with an amplification factor of -R20 / R10.

[0040] In this embodiment, the subtraction circuit includes: R21, R22, R23, R24, and U4. The resistance values ​​of R21, R22, R23, and R24 are equal, and the output value of U4 = the output value of U3 - the output value of U2.

[0041] U2, U3, U'2, and U'3 are specifically modeled as OP117G, a precision operational amplifier. This operational amplifier features low noise, low offset, and low drift, making it suitable for applications requiring high amplification accuracy. Furthermore, it boasts a wide power supply range and high common-mode rejection ratio, ensuring stable performance under various operating conditions.

[0042] In this embodiment, the (A+B) / 2 circuit includes R25, R26, and U5, and the output value of U5 = (output value of U4 + output value of U'4) / 2.

[0043] U4, U'4, and U5 are model INA154U, a high-speed precision differential amplifier. Key parameters: power supply voltage: ±15V dual power supply; input bias voltage: ≤0.75mV; common-mode rejection ratio: 80dB; operating current: 2.4mA (typical). It is suitable for signal processing scenarios, such as circuit designs for instruments and meters where high precision is required.

[0044] It can detect changes in radio frequency power with high precision so as to adjust the power output in a timely manner, ensuring the analytical accuracy of the mass spectrometer. It can detect changes in radio frequency signals in a short time, feed them back to the control system, and make rapid adjustments to maintain a stable radio frequency power output, avoiding the influence of external interference on the detection results and ensuring accurate and reliable detection signals.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A radio frequency detection circuit system, comprising a radio frequency signal RF+, a radio frequency signal RF-, and a full-wave detection circuit, characterized in that: The radio frequency signal RF+ is connected to the full-wave detector circuit. The two output terminals of the full-wave detector circuit are connected to the upper half-cycle filter circuit and the lower half-cycle filter circuit, respectively. The output circuits of the upper half-cycle filter circuit and the lower half-cycle filter circuit are respectively connected to compensation and amplification circuits. The output circuits of the two compensation and amplification circuits are connected to the subtraction circuit. The circuit principle of the back end connection of the RF signal RF- is the same as that of the back end connection of the RF signal RF+. The two subtraction circuits at the end of the circuits of the RF signal RF+ and the RF signal RF- are both connected to the input terminal of the (A+B) / 2 circuit. The output circuit of the subtraction circuit is connected to the input terminal of the (A+B) / 2 circuit, and the RF amplitude feedback is output through the (A+B) / 2 circuit.

2. The radio frequency detection circuit system according to claim 1, characterized in that: The radio frequency signal RF+ and radio frequency signal RF- are V1 and V'1, respectively. V1 and V'1 are 1MHz sine signals with equal amplitude and 180° phase difference.

3. The radio frequency detection circuit system according to claim 1, characterized in that: The full-wave detector circuit includes: C1, C2, C3, C4, C5, R1, R2, R3, D1, D2, and U1.

4. The radio frequency detection circuit system according to claim 1, characterized in that: The filtering circuit includes: T1, C6, and C7.

5. The radio frequency detection circuit system according to claim 1, characterized in that: In the upper half-cycle filter circuit and its downstream compensation and amplification circuit, VCC, R4, D3, and C8 constitute a positive voltage diode voltage drop compensation circuit.

6. The radio frequency detection circuit system according to claim 1, characterized in that: In the lower half-cycle filter circuit and its downstream compensation and amplification circuit, VDD, R5, D4, and C9 constitute a negative voltage diode voltage drop compensation circuit.

7. The radio frequency detection circuit system according to claim 1, characterized in that: The compensation and amplification circuit, in which VCC, VDD, R8, R9, R13, R14, R17, and R17 form a dual-supply resistor network, is used for circuit compensation.

8. The radio frequency detection circuit system according to claim 1, characterized in that: The compensation and amplification circuit consists of R6, R19, R15, and U2 forming an inverting amplifier circuit to amplify the lower half-cycle amplitude detection voltage value, with an amplification factor of -R19 / R6; and R10, R20, R18, and U3 forming an inverting amplifier circuit to amplify the upper half-cycle amplitude detection, with an amplification factor of -R20 / R10.

9. The radio frequency detection circuit system according to claim 1, characterized in that: The subtraction circuit includes: R21, R22, R23, R24, and U4. The resistance values ​​of R21, R22, R23, and R24 are equal, and the output value of U4 = the output value of U3 - the output value of U2.

10. The radio frequency detection circuit system according to claim 1, characterized in that: The (A+B) / 2 circuit includes R25, R26, and U5. The output value of U5 is equal to (the output value of U4 + the output value of U'4) / 2.

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