CN107907904A - A kind of circuit and method for improving operating point measurement sensitivity - Google Patents

Abstract

The invention discloses a kind of circuit and method for improving operating point measurement sensitivity, interlock circuit includes：Beam position detector, envelope detection circuit, ac-coupled device, high resistant difference amplifier, notch filter and bandpass filter；Wherein：The two-way output terminal of the beam position detector connects an envelope detection circuit respectively, each envelope detection circuit output terminal connects an ac-coupled device respectively, the reverse input end and positive output terminal of the corresponding connection high resistant difference amplifier of output terminal of two ac-coupled devices, the output terminal connection notch filter of high resistant difference amplifier, the output terminal connection bandpass filter of notch filter.Program principle is simple, and circuit structure is easily built, and compared with conventional operating point measuring method, the detection sensitivity of work dot frequency can be greatly improved, and is particularly suitable for the real-time detection of operating point and parameter feedback in synchrotron radiation light source electronic storage ring.

Description

A circuit and method for improving working point measurement sensitivity

technical field

The invention relates to the technical field of charged particle accelerators, in particular to a circuit and a method for improving the measurement sensitivity of an operating point.

Background technique

The operating point is one of the most important parameters of the electron storage ring of a synchrotron radiation source. In conventional measurement methods, it is usually necessary to apply a certain excitation to the storage beam to effectively detect the operating point, and the disturbance of the beam makes the measurement of the operating point very limited in application. The limit diffraction storage ring proposed in recent years is the most advanced synchrotron radiation light source. Its emittance is usually tens of picometer radians, the stability of the beam trajectory is usually required to be on the order of hundreds of nanometers, and the dynamic aperture is significantly smaller than that of the third-generation light sources. Therefore, it is an urgent need for a new generation of light sources to reduce the disturbance of the stored beam current during the measurement of the operating point as much as possible. Improving the measurement sensitivity of the operating point is an effective way to reduce the impact on the beam current and can effectively expand the measurement of the operating point. applications, such as real-time operating point detection and feedback, radio frequency real-time detection and feedback, etc. However, there is no more effective solution at present.

Contents of the invention

The purpose of the present invention is to provide a circuit and method for improving the measurement sensitivity of the working point, which can effectively improve the detection sensitivity of the working point, thereby solving the adverse effect of the need for disturbing the measurement of the beam current in the existing measurement technology.

The purpose of the present invention is achieved through the following technical solutions:

A circuit for improving the measurement sensitivity of an operating point, comprising: a beam position detector, an envelope detection circuit, an AC coupler, a high-impedance differential amplifier, a notch filter, and a bandpass filter; wherein:

The two output terminals of the beam position detector are respectively connected to an envelope detection circuit, and the output terminals of each envelope detection circuit are respectively connected to an AC coupler, and the output terminals of the two AC couplers are respectively connected to high-impedance differential The reverse input terminal and the positive output terminal of the amplifier, the output terminal of the high-impedance differential amplifier are connected with a notch filter, and the output terminal of the notch filter is connected with a band-pass filter.

A method for improving the measurement sensitivity of an operating point, comprising: using a beam position detector to couple beam signals, and the output two-way coupled beam signals are respectively subjected to detection processing by an envelope detection circuit, and the obtained two-way detection-processed The opposite electrode signals are respectively input to the reverse input terminal and positive output terminal of the high-impedance differential amplifier through an AC coupler, and finally passed through the notch filter and the band-pass filter in turn to subtract the output of the high-impedance differential amplifier. The signal is filtered.

It can be seen from the technical solution provided by the present invention that the principle of the solution is simple, and the circuit structure is easy to construct. Compared with the conventional working point measurement method, the detection sensitivity of the working point frequency can be greatly improved, and it is especially suitable for electronic storage rings of synchrotron radiation sources. Real-time detection and parameter feedback of the middle working point.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

Fig. 1 is a kind of circuit schematic diagram that improves working point measurement sensitivity provided by the embodiment of the present invention;

FIG. 2 is a schematic diagram of envelope detection based on diode detection provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of a high-impedance differential amplifier provided by an embodiment of the present invention;

Fig. 4 is the circuit principle diagram of the notch filter provided by the embodiment of the present invention;

Fig. 5 is the magnitude-frequency response curve of the notch filter provided by the embodiment of the present invention;

6 is a schematic circuit diagram of a bandpass filter provided by an embodiment of the present invention;

Fig. 7 is the amplitude-frequency response curve of the band-pass filter provided by the embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the electronic storage ring of synchrotron radiation source, the working point measurement system is an essential part. The operating point is obtained by measuring the spectrum of the beam oscillation signal. The common method is to directly collect the beam signal for spectrum analysis. Since the beam signal is a narrow pulse modulation signal, the main frequency component in the beam signal is the cyclotron frequency, and the frequency component at the operating point accounts for a very low proportion. Therefore, the beam is usually excited in real time to increase the frequency component at the operating point. Compared with conventional methods, the high-sensitivity working point measurement method of the present invention effectively improves signal detection sensitivity.

As shown in Figure 1, a circuit for improving the measurement sensitivity of the working point is provided for the embodiment of the present invention, which mainly includes: a beam position detector 1, an envelope detection circuit 2, an AC coupler 3, a high-impedance differential amplifier 4, Notch filter 5 and bandpass filter 6; Wherein:

The two output terminals of the beam position detector 1 are respectively connected to an envelope detection circuit 2, and the output terminals of each envelope detection circuit 2 are respectively connected to an AC coupler 3, and the output terminals of the two AC couplers 3 correspond to The inverting input terminal and the forward output terminal of the high-impedance differential amplifier 4 are connected, the output terminal of the high-impedance differential amplifier 4 is connected to the notch filter 5 , and the output terminal of the notch filter 5 is connected to the bandpass filter 6 .

Afterwards, the signal output by the band-pass filter 6 is sent to the low noise amplifier for pre-amplification, and the pre-amplified signal is finally sent to the ADC for digital processing.

In the embodiment of the present invention, the beam position detector may be composed of a pair of opposite electrodes or four axisymmetric electrodes. A pair of opposite electrodes can be used to measure beam position oscillation in one plane direction, and four axisymmetric electrodes can be used to measure beam position oscillation in two orthogonal directions.

In the embodiment of the present invention, envelope detection technology is used to perform detection processing on the coupled beam current signal, and the envelope detection circuit is realized by a diode detection circuit or a triode detection circuit. Exemplarily, a diode detection circuit as shown in Figure 2 can be used. As shown in Figure 2, R1 is an input matching resistor, and a chip resistor with a resistance value of 50 ohms is selected. D1, R2 and C1 can detect the operating point according to the needs frequency to select. Assuming that the operating point frequency to be detected is 2.036MHz in the horizontal direction and 1.622MHz in the vertical direction, then D1 selects HSMS-2805, R2 selects a chip resistor with a resistance of 1000 ohms, and C1 selects a chip capacitor with a capacitance of 510 picofarads. The attenuation time constant of the detection circuit is calculated to be t=0.51 microseconds.

In the embodiment of the present invention, the AC coupler may be implemented by connecting capacitors in series.

In the embodiment of the present invention, in order to reduce the impact on the detection circuit, the input impedance of the differential amplifier is increased as much as possible, so the high-impedance differential amplifier can be a differential operation unit of the instrument amplifier type. Exemplarily, an AD8429 instrumentation amplifier integrated circuit can be selected, as shown in FIG. 3 , the gain resistor R1 can be a chip resistor with a resistance value of 6000 ohms.

In the embodiment of the present invention, the notch filter and the band-pass filter are used to filter out the convolution frequency and the harmonic component respectively, so as to effectively improve the power component of the frequency signal at the working point.

In the embodiment of the present invention, the notch filter can be a double-T notch filter and an active Chebyshev II filter, as shown in Figure 4, the operating frequency of the notch filter is 4.534MHz, and its amplitude-frequency response The curve is shown in Figure 5.

In the embodiment of the present invention, the bandpass filter can be an 8-order Butterworth filter, as shown in FIG. 6 , and its amplitude-frequency response curve is shown in FIG. 7 , with a center frequency of 1.06 MHz and a 3dB bandwidth of 2 MHz.

Based on the above scheme, the electronic storage ring of Hefei Light Source is used as the platform, its high-frequency frequency is 204MHz, the gyro frequency is 4.534MHz, the maximum operating current is 360mA, the decimal part of the horizontal working point is 0.4490, and the decimal part of the vertical working point is 0.3577 . Designed according to the beam current parameters of Hefei Light Source, using the circuit provided by the invention, the real-time detection of the working point can be realized without exciting the beam current. Compared with the original working point measurement system, the sensitivity is increased by about 17dB.

Another embodiment of the present invention also provides a method for improving the measurement sensitivity of the operating point, which can be realized based on the "circuit" provided in the foregoing embodiments, mainly as follows: the beam position detector is used to couple the beam signal, and the output two-way The coupled beam current signals are respectively processed by an envelope detection circuit, and the obtained two-way detection-processed relative electrode signals are respectively input to the reverse input terminal and the forward output terminal of the high-impedance differential amplifier through a corresponding AC coupler. Finally, the subtracted signal output by the high-impedance differential amplifier is filtered through a notch filter and a band-pass filter in sequence.

In the embodiment of the present invention, the beam position detector is composed of a pair of opposite electrodes or four axisymmetric electrodes.

In the embodiment of the present invention, the envelope detection circuit is realized by a diode detection circuit or a triode detection circuit.

In the embodiment of the present invention, the AC coupler is implemented by connecting capacitors in series.

In the embodiment of the present invention, the high-impedance differential amplifier is a differential operation unit of an instrumentation amplifier type.

It should be noted that, the specific implementation manners of the functions implemented by each device included in the above method have been described in detail in the foregoing embodiments, so details are not repeated here.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. A circuit for improving working point measurement sensitivity is characterized in that it comprises: beam position detector, envelope detection circuit, AC coupler, high-impedance differential amplifier, notch filter and band-pass filter; wherein: The two output terminals of the beam position detector are respectively connected to an envelope detection circuit, and the output terminals of each envelope detection circuit are respectively connected to an AC coupler, and the output terminals of the two AC couplers are respectively connected to high-impedance differential The reverse input terminal and the positive output terminal of the amplifier, the output terminal of the high-impedance differential amplifier are connected with a notch filter, and the output terminal of the notch filter is connected with a band-pass filter. 2 . The circuit for improving the measurement sensitivity of the working point according to claim 1 , wherein the beam position detector is composed of a pair of opposite electrodes or 4 axisymmetric electrodes. 3 . 3 . The circuit for improving the measurement sensitivity of the working point according to claim 1 , wherein the envelope detection circuit is realized by a diode detection circuit or a triode detection circuit. 4 . 4. A circuit for improving the measurement sensitivity of an operating point according to claim 1, wherein the AC coupler is implemented by connecting capacitors in series. 5 . The circuit for improving the measurement sensitivity of the operating point according to claim 1 , wherein the high-impedance differential amplifier is a differential operation unit of an instrument amplifier type. 6 . 6. A method for improving the measurement sensitivity of an operating point, comprising: using a beam position detector to couple beam signals, and the output two-way coupled beam signals are respectively subjected to detection processing by an envelope detection circuit, and the obtained The opposite electrode signals after the two-way detection and processing are respectively input to the reverse input terminal and positive output terminal of the high-impedance differential amplifier through an AC coupler, and finally pass through the notch filter and the band-pass filter to the high-impedance differential amplifier in turn. The output signal after subtraction is filtered. 7. A method for improving the measurement sensitivity of the working point according to claim 6, wherein the beam position detector is composed of a pair of opposite electrodes or 4 axisymmetric electrodes. 8. A method for improving the measurement sensitivity of the working point according to claim 6, characterized in that, the envelope detection circuit is realized by a diode detection circuit or a triode detection circuit. 9. A method for improving the measurement sensitivity of the working point according to claim 6, characterized in that the AC coupler is implemented by connecting capacitors in series. 10 . The method for improving the measurement sensitivity of the working point according to claim 6 , wherein the high-impedance differential amplifier is a differential operation unit of an instrumentation amplifier type. 11 .