CN112073015A - Automatic gain feedback control method and device - Google Patents

Automatic gain feedback control method and device Download PDF

Info

Publication number
CN112073015A
CN112073015A CN202010256714.4A CN202010256714A CN112073015A CN 112073015 A CN112073015 A CN 112073015A CN 202010256714 A CN202010256714 A CN 202010256714A CN 112073015 A CN112073015 A CN 112073015A
Authority
CN
China
Prior art keywords
signal
feedback control
controlled system
output
input
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010256714.4A
Other languages
Chinese (zh)
Inventor
韩永光
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kunshan Nier Precision Instrument Co ltd
Original Assignee
Kunshan Nier Precision Instrument Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kunshan Nier Precision Instrument Co ltd filed Critical Kunshan Nier Precision Instrument Co ltd
Priority to CN202010256714.4A priority Critical patent/CN112073015A/en
Publication of CN112073015A publication Critical patent/CN112073015A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers
    • H03G3/3042—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers in modulators, frequency-changers, transmitters or power amplifiers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/022—Circuit arrangements, e.g. for generating deviation currents or voltages ; Components associated with high voltage supply
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/004—Control by varying the supply voltage

Abstract

The invention provides an automatic gain feedback control method, firstly obtaining an output signal of a controlled system and a reference signal with preset frequency, and delaying the reference signal; then, a feedback control signal is obtained according to the delayed reference signal and the output signal of the controlled system; and finally, adjusting the input signal of the controlled system according to the feedback control signal. The invention also provides an automatic gain feedback control device. According to the invention, the delayed reference signal and the output signal of the controlled system are processed to obtain the feedback control signal, and the amplitude of the input signal of the controlled system is changed according to the feedback control signal, so that the amplitude of the signal with the same frequency as the reference signal in the output of the controlled system is constant, and the amplitude of other frequency signals contained in the output signal of the controlled system is not influenced. The invention can control sine wave signals or sine wave frequency sweeping signals within 10M and can accurately control the amplitude of the output signals of the high-voltage radio frequency power supply.

Description

Automatic gain feedback control method and device
Technical Field
The invention relates to the technical field of mass spectrometry, in particular to an automatic gain feedback control method and device for amplitude of a high-voltage radio frequency power supply of a mass spectrometer.
Background
The mass spectrometer is a scientific instrument for performing qualitative and quantitative substance analysis and component identification on substances according to the mass-to-charge ratio of ions, and has high resolution and sensitivity. Generally, mass spectrometers are composed primarily of an ion source, an ion transport system, a mass analyzer, a detector, a vacuum system, and a data acquisition system. There are various types of mass analyzers, such as quadrupole rods, ion traps, time-of-flight, fourier transform ion cyclotron resonance traps, and the like. Ion trap mass analyzers can operate at higher gas pressures than other mass analyzers, making them one of the ideal choices for miniaturized mass spectrometers.
When mass analysis is performed using an ion trap mass analyzer, rf voltages are applied to the electrodes of the mass analyzer and scanned to screen ions for mass analysis. The sine wave frequency scanning mode is a brand new scanning mode. In the scan phase, a sine wave frequency scan pattern excites ions with a sine wave of constant amplitude and constant frequency over time. The sine wave frequency sweep pattern can further extend the mass range of mass spectrometry measurements relative to the amplitude sweep pattern for the same power consumption and volume. And because the sine wave does not contain steep edges, the electromagnetic compatibility is also improved to a certain extent.
In the scanning phase, if the amplitude of an RF (Radio Frequency) signal cannot be kept stable, even if the amplitude of the change is small, the peak of a mass spectrum is shifted. Stability of the RF signal amplitude is important.
The use of feedback control methods to stabilize the gain of an amplifier is one of the most widely used in electronic circuits. And a circuit for automatically controlling the Gain according to the voltage amplitude outputted from the system as a feedback signal is called AGC (Automatic Gain Control). Whereas the conventional AGC circuit adjusts the gain of the amplifying circuit by detecting the average value of the output voltage. When the average value of the output voltage is smaller than the set average value of the voltage, the gain of the amplifier is increased, otherwise, the gain of the amplifier is reduced.
The AGC circuit realizes automatic gain control by converting the average value of the output voltage into a suitable dc frequency through a detection circuit, which is generally composed of a detection circuit and a low-pass filter, and feeding back the dc frequency to a gain control terminal of a voltage-controlled gain controller.
The simplest detector circuit is a diode peak detector circuit for the detector circuit portion of the output voltage. With this kind of circuit, when the amplitude of the input signal is fixed, the average amplitude of the output signal of the diode peak detection circuit will change with the change of the frequency of the input signal. The peak voltage detection circuit and the effective value detection circuit can be formed by operational amplifiers. Integrated effective value/peak detection chips may also be used, with the accuracy of the detection circuit made using the integrated chip being limited primarily by device performance.
The low-pass filtering is to average the signal output by the detection circuit, i.e. extract the dc component in the signal, and then properly process the dc component according to the characteristics of the selected voltage-controlled gain amplifier, so as to obtain the control voltage of the voltage-controlled gain amplifier. The time constant of the low pass filter typically determines the reaction time of the AGC circuit. If the time constant is too large, the AGC action will be sluggish, i.e. it takes some time for the gain adjustment action to occur after the output changes. If the time constant is too small, a counter modulation phenomenon may occur. Therefore, the filtering time of the low-pass filter is longer than the period of the lowest frequency component in the input signal.
Because the transfer function of the radio frequency high-voltage module is changed due to the change of the temperature when the radio frequency high-voltage module works for a long time, the output amplitude is changed, the high-voltage radio frequency power supply is controlled by using an AGC control module, the output amplitude can be more stable, and the analysis result obtained by a mass spectrometer is more accurate.
However, the inventor finds that the AGC circuit of the prior art has the following defects when implementing the present invention: in the case of the conventional detector circuit, if the input signal is a combination of signals of a plurality of frequencies, the result of detection is the average amplitude of the voltage of the mixed signal, and it is not possible to extract amplitude information of a signal of one of the frequencies.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide an automatic gain feedback control method and apparatus, so as to overcome the defect that in the prior art, when an input signal is formed by combining signals of multiple frequencies, amplitude information of a certain frequency signal cannot be extracted.
In order to achieve the above object, the present invention provides an automatic gain feedback control method, comprising:
A. acquiring an output signal of a controlled system;
B. acquiring a reference signal with preset frequency, and delaying the reference signal;
C. obtaining a feedback control signal according to the delayed reference signal and the output signal of the controlled system;
D. and adjusting the input signal of the controlled system according to the feedback control signal, so as to control the amplitude of the signal with the same frequency as the reference signal in the output signal of the controlled system to be constant.
Further, the step C specifically includes:
c1, mixing the delayed reference signal and the output signal of the controlled system to obtain a mixing signal;
c2, performing low-pass filtering on the mixing signal to obtain a filtering signal;
and C3, acquiring the feedback control signal according to the filtering signal.
Further, the step C1 specifically includes:
according to the formula
Figure BDA0002437622940000031
Obtaining a mixing signal UA(t)，
Wherein U isA(t) is a mixing signal; y (t) is the output signal of the controlled system, y (t) ar (t) + y1(t); r (t) is a delayed reference signal, and r (t) is Vrcos (t), reference signal r (t)1)，r(t1)＝Vrcos(ωt1) Where t is t1+ Δ t, Δ t is the delay time.
Further, the step C2 specifically includes:
will mix the signal UA(t) low-pass filtering to obtain a filtered signal
Figure BDA0002437622940000032
Further, the step C3 specifically includes:
c31, mixing UA_LPF(t) is obtained by squaring
Figure BDA0002437622940000033
C32, mixing (V)A-VB) After passing through a PI control circuit, a feedback control signal V is obtainedkIn which V isBIs a comparison voltage.
Further, the step D specifically includes:
and mixing the original input signal of the controlled system with the feedback control signal, wherein the output signal after mixing is used as the input signal after being adjusted by the controlled system.
The invention also provides an automatic gain feedback control device, which comprises a time delay unit, a feedback control signal acquisition unit and a signal adjustment unit;
the delay unit is used for receiving a reference signal with preset frequency and delaying the reference signal;
the feedback control signal acquisition unit is respectively connected with the delay unit and the output end of the controlled system, and is used for receiving the output signal of the controlled system and obtaining a feedback control signal according to the output signal of the controlled system and the delayed reference signal output by the delay unit;
the signal adjusting unit is respectively connected with the input end of the controlled system and the feedback control signal acquiring unit, and is used for receiving the original input signal of the controlled system and adjusting the input signal of the controlled system according to the feedback control signal acquired by the feedback control signal acquiring unit, so that the amplitude of the signal with the same frequency as the reference signal in the output signal of the controlled system is controlled to be constant.
Further, the feedback control signal obtaining unit includes a second mixer, a low-pass filter, and a PI controller;
the second mixer is respectively connected with the delay unit and the output end of the controlled system, and is used for receiving the output signal of the controlled system and mixing the delayed reference signal and the output signal of the controlled system to obtain a mixed signal;
the low-pass filter is connected with the second mixer and is used for performing low-pass filtering on the mixing signal to obtain a filtering signal;
and the PI controller is respectively connected with the low-pass filter and the signal adjusting unit and is used for acquiring a feedback control signal according to the filtering signal and sending the feedback control signal to the signal adjusting unit.
Further, the feedback control signal acquisition unit further comprises an external input comparison voltage interface and/or an internal input comparison voltage interface; when the external input comparison voltage interface is connected with the PI controller, the comparison voltage is input into the PI controller through the external input comparison voltage interface; when the internal input comparison voltage interface is connected with the PI controller, the comparison voltage is input into the PI controller through the internal input comparison voltage interface.
Further, the signal adjusting unit includes a first mixer, and the first mixer is connected to the input end of the controlled system and the PI controller, and is configured to receive an original input signal of the controlled system, mix the feedback control signal sent by the PI controller and the original input signal of the controlled system, and send an output signal after mixing to the input end of the controlled system.
According to the invention, the delayed reference signal and the output signal of the controlled system are processed to obtain the feedback control signal, and the amplitude of the input signal of the controlled system is changed according to the feedback control signal, so that the amplitude of the signal with the same frequency as the reference signal in the output of the controlled system is constant, and the amplitude of other frequency signals contained in the output signal of the controlled system is not influenced. The invention can control sine wave signals or sine wave frequency sweeping signals within 10M and can accurately control the amplitude of the output signals of the high-voltage radio frequency power supply.
Drawings
Fig. 1 is a flow chart of an automatic gain feedback control method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an automatic gain feedback control apparatus according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a high voltage RF power supply of a mass spectrometer according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a PI controller according to an embodiment of the present invention;
FIGS. 5 a-5 b are waveform diagrams of the output of the RF power source when the high voltage RF power source is frequency swept according to the embodiment of the present invention;
FIG. 6a is a waveform diagram of a reference signal when the high voltage RF power source is frequency swept in accordance with an embodiment of the present invention;
FIG. 6b is a waveform diagram of comparative voltages when the high voltage RF power supply is frequency swept in accordance with the present invention;
FIG. 7 is a waveform diagram of a reference signal when the high voltage RF power supply is amplitude swept in accordance with an embodiment of the present invention;
FIG. 8a is a waveform diagram of the comparison voltage when the high voltage RF power supply is amplitude-scanned and the comparison voltage is constant according to the embodiment of the present invention;
FIG. 8b is a waveform diagram of the final output of the controlled system when the high voltage RF power source is amplitude-scanned and the comparison voltage is constant according to the embodiment of the present invention;
FIG. 9a is a waveform diagram of the comparison voltage when the high voltage RF power supply is amplitude swept and the comparison voltage is varied according to the embodiment of the present invention;
FIG. 9b is a waveform diagram of the final output of the controlled system when the high voltage RF power supply is amplitude swept and compared for voltage variation according to the embodiment of the present invention.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and examples.
Example 1
A high-voltage radio frequency power supply of a mass spectrometer according to an embodiment of the present invention is an automatic gain feedback control method according to an embodiment of the present invention, as shown in fig. 1, the method including the steps of:
and step s101, acquiring an output signal of the controlled system.
Step s102, obtaining a reference signal with a preset frequency, and delaying the reference signal. In this embodiment, the reference signal is a preset sinusoidal signal, and is consistent with the frequency of the signal to be controlled. If the final output of the controlled system is formed by aliasing of sinusoidal signals of 1Mhz and 20Khz, but the amplitude of the sinusoidal signal corresponding to the controlled 1Mhz is fixed, and not the average voltage amplitude absorbed by the final output of the controlled system, a reference signal with the frequency of 1Mhz needs to be input (because the amplitude of the 1Mhz signal is to be controlled), and the amplitude of the reference signal is within the allowable amplitude range (the amplitude should be fixed and not changed). When the controlled radio frequency power supply is amplitude scanning, the frequency of the reference signal is fixed, and the waveform is a sine signal; when the controlled rf power source is frequency swept, the frequency of the reference signal is consistent with the frequency variation of the final output of the controlled system (because the frequency of the tracked control signal is varied), and the waveform is a sinusoidal signal.
In this embodiment, first, let the reference signal be r (t)1) The output signal of the controlled system is y (t) ═ Ar (t) + y1(t), wherein t is t1+ Δ t, the time required by the delay circuit to delay the reference signal is Δ t.
And step s103, obtaining a feedback control signal according to the delayed reference signal and the output signal of the controlled system. In this embodiment, the steps specifically include:
(1) and mixing the delayed reference signal and the output signal of the controlled system to obtain a mixed signal. The method specifically comprises the following steps: according to the formula
Figure BDA0002437622940000071
Obtaining a mixing signal UA(t); wherein U isA(t) is a mixing signal; y (t) is the output signal of the controlled system, y (t) ar (t) + y1(t); r (t) is a delayed reference signal, and r (t) is Vrcos (t), reference signal r (t)1)，r(t1)＝Vrcos(ωt1) Where t is t1+ Δ t, Δ t is the delay time.
(2) And carrying out low-pass filtering on the frequency mixing signal to obtain a filtering signal. The method specifically comprises the following steps: will mix the signal UA(t) low-pass filtering to obtain a filtered signal
Figure BDA0002437622940000077
(3) And acquiring the feedback control signal according to the filtering signal. The method specifically comprises the following steps: firstly, U is firstlyA_LPF(t) is obtained by squaring
Figure BDA0002437622940000072
Then (V)A-VB) After passing through a PI control circuit, a feedback control signal V is obtainedkIn which V isBIs a comparison voltage.
In addition, if the reference signal is not delayed, the reference signal and the output signal of the controlled system are directly mixed, and the mixed signal is filtered by a low-pass filter, and the process is as follows:
firstly, the controlled system outputs a signal y (t) and a reference signal r (t)1) After passing through a mixer, a signal U is obtainedA' (t) then
Figure BDA0002437622940000073
Wherein
Figure BDA0002437622940000074
Then the signal UA' (t) is filtered by a low-pass filter to obtainTo
Figure BDA0002437622940000075
Wherein
Figure BDA0002437622940000076
Through the comparison, the reference signal is subjected to time delay processing, so that the amplitude of the controlled signal can be prevented from changing together when the frequency of the tracked signal changes, the AGC feedback circuit can track the component of single frequency change in the output signal of the controlled system, and then the amplitude of the AGC feedback circuit is controlled to be constant.
And step s104, adjusting the input signal of the controlled system according to the feedback control signal, so as to control the amplitude of the signal with the same frequency as the reference signal in the output signal of the controlled system to be constant. In this embodiment, the following concrete steps are performed: and mixing the original input signal of the controlled system with the feedback control signal, wherein the output signal after mixing is used as the input signal after being adjusted by the controlled system.
According to the invention, the delayed reference signal and the output signal of the controlled system are processed to obtain the feedback control signal, and the amplitude of the input signal of the controlled system is changed according to the feedback control signal, so that the amplitude of the signal with the same frequency as the reference signal in the output of the controlled system is constant, and the amplitude of other frequency signals contained in the output signal of the controlled system is not influenced.
Example 2
As shown in fig. 2, an automatic gain feedback control apparatus according to an embodiment of the present invention includes a delay unit 21, a feedback control signal obtaining unit 22, and a signal adjusting unit 23; the feedback control signal acquisition unit 22 is respectively connected with the delay unit 21 and the signal adjustment unit 23; when the device is applied to a controlled system 24, the output end of the controlled system 24 is connected with the feedback control signal acquisition unit 22, and the input end is connected with the signal adjusting unit 23.
The delay unit 21 is configured to receive a reference signal with a preset frequency, and delay the reference signal.
The feedback control signal obtaining unit 22 is configured to receive the output signal of the controlled system 24, and obtain a feedback control signal according to the output signal of the controlled system 24 and the delayed reference signal output by the delay unit 21. The feedback control signal acquiring unit 22 includes a second mixer 221, a low pass filter 222, and a PI controller 223. The second mixer 221 is connected to the output ends of the delay unit 21 and the controlled system 24, and is configured to receive the output signal of the controlled system 24, and mix the delayed reference signal and the output signal of the controlled system 24 to obtain a mixed signal; the low-pass filter 222 is connected to the second mixer 221, and configured to perform low-pass filtering on the mixed signal to obtain a filtered signal; the PI controller 223 is respectively connected to the low-pass filter 222 and the signal adjusting unit 23, and is configured to obtain a feedback control signal according to the filtering signal, and send the feedback control signal to the signal adjusting unit 23. In addition, the feedback control signal obtaining unit 22 further includes an external input comparison voltage interface and/or an internal input comparison voltage interface; when the external input comparison voltage interface is connected with the PI controller 223, the comparison voltage is input to the PI controller 223 through the external input comparison voltage interface; when the internal input comparison voltage interface is connected to the PI controller 223, the comparison voltage is input to the PI controller 223 through the internal input comparison voltage interface.
The structure of a PI controller according to an embodiment of the present invention is shown in fig. 4, in which
R37＝R35，
I＝(VA-VB)/R37，
VK＝-(R36/R37)(VA-VB)-1/(C28R37)∫(VA-VB)dt。
For the use of the external input interface and the internal input interface: in this embodiment, three connection interfaces, A (V of PI controller) are usedBEnd), B (external input interface), C (internal input interface). Jumper wires are used to select whether to connect the AB or the AC, i.e. to select both the externally input comparison voltage and the internal comparison voltage. When it is desired that the output voltage is varied (for example, linearly, in the case where the controlled rf power supply is in an amplitude sweep mode), it is necessary to externally input a varying voltage corresponding to the desired variation to control the variation of the output amplitude, and the AB is connected. When it is desired that the output amplitude is fixed (i.e. the controlled rf power supply is frequency swept and needs to be stabilized), the voltage V is comparedBShould be fixed, at this time an internal input voltage (jumper connected AC, internal V) may be selectedBCan be adjusted by an adjusting knob), or a comparison voltage V with fixed amplitude can be selected and input externallyB(jumper connection AB).
The signal adjusting unit 23 is configured to receive an original input signal of the controlled system 24, and adjust the input signal of the controlled system 24 according to the feedback control signal obtained by the feedback control signal obtaining unit 22, so as to control the amplitude of a signal having the same frequency as the reference signal in the output signal of the controlled system 24 to be constant. In this embodiment, the signal adjusting unit adopts a first mixer, and the first mixer is respectively connected to the input end of the controlled system 24 and the PI controller 223, and is configured to receive an original input signal of the controlled system 24, mix a feedback control signal sent by the PI controller 223 and the original input signal of the controlled system 24, and send a mixed output signal to the input end of the controlled system 24.
In the embodiment, the amplitude of the input signal is adjusted in real time by using the mixer and the low-pass filter, so that the amplitude of the output signal is kept unchanged. The embodiment can control the sine wave signal or the sine wave frequency sweeping signal within 10M, and can accurately control the amplitude of the output signal of the high-voltage radio frequency power supply. The sine wave signal and the sine wave frequency sweep signal described in this embodiment respectively refer to whether the controlled signal is a sine signal with a fixed frequency or a sine frequency sweep signal (i.e., a sine signal with a frequency that continuously changes from high to low or from low to high within a frequency band).
Example 3
In this embodiment, a mixer and a low-pass filter are used to extract the amplitude of a signal with a specified frequency from an output signal of a high-voltage rf module to adjust the amplitude of an input signal, so as to keep the amplitude of the frequency signal unchanged during output.
The high-voltage radio frequency power supply applied to the mass spectrometer mainly has two working modes, one mode is amplitude scanning, namely, a sinusoidal signal with constant frequency and linear amplitude variation is used for scanning to realize the mass analysis of ions; the other is frequency scanning, that is, scanning with a sinusoidal signal with constant amplitude and linearly changing frequency to realize mass analysis of ions. While a sine wave frequency sweep is one of the frequency sweeps, it is emphasized that the signal it outputs is a sinusoidal signal.
The structure of the high-voltage radio frequency power supply of the mass spectrometer of the embodiment is shown in fig. 3, and includes an RF module and an AGC feedback control module, where an input and an output of the RF module are respectively connected to the AGC feedback control module through an amplifying/attenuating circuit, and the AGC feedback control module is the automatic gain feedback control device of the present invention.
Referring to fig. 3, the AGC feedback control module includes a delay circuit, a mixer 2, a low pass filter LPF, a PI controller, and a mixer 1, the mixer 2 is respectively connected to output terminals of the delay circuit, the low pass filter LPF, and the RF module, an output terminal of the low pass filter LPF is connected to an input terminal of the PI controller, and the mixer 1 is respectively connected to an output terminal of the PI controller and an input terminal of the RF module, and receives an original input signal U of the RF moduleIN。
When the high-voltage radio frequency power supply is used for frequency scanning, the working steps are as follows:
the method comprises the following steps: reference signal UrReference signal input connected to AGC feedback control moduleThe input interface is connected with a delay circuit to obtain UR. First, assume that the reference signal is Ur(t)＝r(t1) The output signal of the controlled system (RF module) is UOUT(t)＝Ar(t)+y1(t), wherein t is t1+ Δ t. The time that the delay circuit needs to delay the reference signal is Δ t. This makes it possible to make the amplitude of the signal of the tracked frequency in the output be the set amplitude when the frequency of the signal to be tracked is changed. In this embodiment, the frequency of the signal to be tracked and controlled is changed, and thus the frequency of the reference signal is also changed.
Step two, extracting UOUTSpecifying amplitude information of a signal of a specified frequency, the steps being as follows:
step 1: output U of system to be controlledOUTAfter suitable scaling, a signal U is obtained3And (t) inputting the signal to a controlled signal input interface of the AGC feedback control module.
Step 2: will U3And URAfter passing through a mixer 2, a signal U is obtained4。
Assume that the reference signal is Ur(t)＝Vrcos(ωt1) The delayed reference signal is UR(t)＝Vrcos(ωt)，U3(t)＝AVrcos(ωt)+V1cos(ω1t)。
Then
Figure BDA0002437622940000111
Figure BDA0002437622940000112
And step 3: output U of mixer 24(t) after filtering and re-evolution by a low-pass filter, the method can be obtained
Figure BDA0002437622940000113
Step three: will (U)5(t)-VB) After passing through a PI control circuit, a feedback control voltage U is obtained6In which V isBThe reference voltage for the set output amplitude can be adjusted by a knob.
Step four: input signal U of original controlled systemINAnd feedback control voltage U6The output signal obtained by multiplying the frequency mixer 1 is used as the input U of the controlled system after feedback1Wherein U isINIs an input interface of the AGC feedback control module, U1And the output interface of the AGC feedback control module.
In this embodiment, the AGC feedback control module has 5 interfaces, wherein 4 interfaces are necessary to be connected, and are input interfaces UIN(connected with the input of the controlled system) and an output interface U1(connected to the input end of the controlled system) and a controlled signal input interface U3(controlled signal is input to the interface, namely the output signal of the controlled system), reference signal is input to the interface Ur(the reference signal has the same frequency as the signal to be tracked), and 1 selective interface is an external input comparison voltage interface VB. The present embodiment further includes two adjusting knobs, namely a delay adjusting knob (for adjusting the delay of the reference signal) and an output amplitude adjusting knob (for adjusting the amplitude of the output of the controlled system).
In this embodiment, when the controlled high voltage rf power supply is scanned by sine wave frequency, the external input comparison voltage interface V is not neededB(ii) a When the controlled high-voltage radio frequency power supply is in amplitude scanning, the voltage interface V can be compared through external inputBA varying comparison voltage is input to achieve a linear variation in amplitude.
(1) In this embodiment, when the high-voltage rf power supply is frequency-swept, assuming that a sinusoidal signal b with other frequencies is superimposed in the output of the rf power supply besides the frequency-swept signal a (the frequency of the signal a is not related to the frequency of the signal b), as shown in fig. 5a, the superimposed output waveform is as shown in fig. 5b, and it is desired to make the output of the frequency-swept signal constant through AGC feedback control, in the AGC feedback control module of this embodiment, a frequency-swept signal that is completely consistent with the controlled signal except for the amplitude is input as a reference signal (used for extracting the amplitude information of the frequency-swept signal in the superimposed output)) And a comparison voltage VB(the voltage may be selected using an external input or using an internal input that adjusts the value of the voltage via a knob). By varying the comparison voltage VBTo adjust the amplitude of the sweep frequency signal in the final output of the controlled system. Corresponding reference signal and comparison voltage VBThe waveforms of (a) are shown in fig. 6a and 6 b.
(2) In this embodiment, when the high voltage rf power supply is amplitude-swept, if the output of the controlled system is a sine wave with a fixed frequency, the reference signal with the same frequency as the output of the controlled system is input, and the voltage V is comparedBTo control the voltage amplitude of the output of the controlled system. The input reference signal waveform is shown in fig. 7. When comparing the voltage VBComparing the voltage V with a constant valueBThe waveform is shown in fig. 8a, and the final output of the controlled system is shown in fig. 8 b; when the input comparison voltage VBWhen it is changed, comparing the voltage VBThe waveform is shown in fig. 9a, and the final output of the controlled system is shown in fig. 9 b.
The AGC feedback control module of this embodiment controls the amplitude of the specified frequency signal in the output of the controlled system to be constant by adjusting the amplitude of the signal input by the controlled system. The AGC feedback control module of the embodiment has small volume and complete interfaces, can be connected to a circuit system which needs to be added with automatic gain control for joint debugging test, and is convenient to use; the broadband can control sine wave signals or frequency sweep signals within 10M; the precision is high, and when the frequency of a controlled signal is within 10M, the output gain can be accurately controlled; high input voltage, capable of inputting signal amplitude up to 20V at most; the anti-interference capability is strong, and the shielding protection can block the interference of external electromagnetic noise.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, devices, means, methods, or steps.

Claims (10)

1. A method of automatic gain feedback control, the method comprising the steps of:
A. acquiring an output signal of a controlled system;
B. acquiring a reference signal with preset frequency, and delaying the reference signal;
C. obtaining a feedback control signal according to the delayed reference signal and the output signal of the controlled system;
D. and adjusting the input signal of the controlled system according to the feedback control signal, so as to control the amplitude of the signal with the same frequency as the reference signal in the output signal of the controlled system to be constant.
2. The automatic gain feedback control method according to claim 1, wherein the step C specifically comprises:
c1, mixing the delayed reference signal and the output signal of the controlled system to obtain a mixing signal;
c2, performing low-pass filtering on the mixing signal to obtain a filtering signal;
and C3, acquiring the feedback control signal according to the filtering signal.
3. The automatic gain feedback control method according to claim 2, wherein the step C1 specifically comprises:
according to the formula
Figure FDA0002437622930000011
Acquisition mixingSignal UA(t)，
Wherein U isA(t) is a mixing signal; y (t) is the output signal of the controlled system, y (t) ar (t) + y1(t); r (t) is a delayed reference signal, and r (t) is Vrcos (t), reference signal r (t)1)，r(t1)＝Vrcos(ωt1) Where t is t1+ Δ t, Δ t is the delay time.
4. The automatic gain feedback control method according to claim 3, wherein the step C2 specifically comprises:
will mix the signal UA(t) low-pass filtering to obtain a filtered signal
Figure FDA0002437622930000012
5. The automatic gain feedback control method according to claim 4, wherein the step C3 specifically comprises:
c31, mixing UA_LPF(t) is obtained by squaring
Figure FDA0002437622930000021
C32, mixing (V)A-VB) After passing through a PI control circuit, a feedback control signal V is obtainedkIn which V isBIs a comparison voltage.
6. The automatic gain feedback control method according to any one of claims 1 to 5, wherein the step D specifically comprises:
and mixing the original input signal of the controlled system with the feedback control signal, wherein the output signal after mixing is used as the input signal after being adjusted by the controlled system.
7. An automatic gain feedback control device is characterized by comprising a time delay unit, a feedback control signal acquisition unit and a signal adjustment unit;
the delay unit is used for receiving a reference signal with preset frequency and delaying the reference signal;
the feedback control signal acquisition unit is respectively connected with the delay unit and the output end of the controlled system, and is used for receiving the output signal of the controlled system and obtaining a feedback control signal according to the output signal of the controlled system and the delayed reference signal output by the delay unit;
the signal adjusting unit is respectively connected with the input end of the controlled system and the feedback control signal acquiring unit, and is used for receiving the original input signal of the controlled system and adjusting the input signal of the controlled system according to the feedback control signal acquired by the feedback control signal acquiring unit, so that the amplitude of the signal with the same frequency as the reference signal in the output signal of the controlled system is controlled to be constant.
8. The automatic gain feedback control device according to claim 7, wherein the feedback control signal obtaining unit includes a second mixer, a low pass filter, and a PI controller;
the second mixer is respectively connected with the delay unit and the output end of the controlled system, and is used for receiving the output signal of the controlled system and mixing the delayed reference signal and the output signal of the controlled system to obtain a mixed signal;
the low-pass filter is connected with the second mixer and is used for performing low-pass filtering on the mixing signal to obtain a filtering signal;
and the PI controller is respectively connected with the low-pass filter and the signal adjusting unit and is used for acquiring a feedback control signal according to the comparison voltage and the filtering signal and sending the feedback control signal to the signal adjusting unit.
9. The automatic gain feedback control device according to claim 8, wherein the feedback control signal obtaining unit further comprises an external input comparison voltage interface and/or an internal input comparison voltage interface; when the external input comparison voltage interface is connected with the PI controller, the comparison voltage is input into the PI controller through the external input comparison voltage interface; when the internal input comparison voltage interface is connected with the PI controller, the comparison voltage is input into the PI controller through the internal input comparison voltage interface.
10. The agc apparatus according to claim 8 or 9, wherein the signal adjusting unit comprises a first mixer, and the first mixer is connected to the input terminal of the controlled system and the PI controller, respectively, and configured to receive an original input signal of the controlled system, mix the feedback control signal sent by the PI controller and the original input signal of the controlled system, and send a mixed output signal to the input terminal of the controlled system.
CN202010256714.4A 2020-04-02 2020-04-02 Automatic gain feedback control method and device Pending CN112073015A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010256714.4A CN112073015A (en) 2020-04-02 2020-04-02 Automatic gain feedback control method and device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010256714.4A CN112073015A (en) 2020-04-02 2020-04-02 Automatic gain feedback control method and device

Publications (1)

Publication Number Publication Date
CN112073015A true CN112073015A (en) 2020-12-11

Family

ID=73658771

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010256714.4A Pending CN112073015A (en) 2020-04-02 2020-04-02 Automatic gain feedback control method and device

Country Status (1)

Country Link
CN (1) CN112073015A (en)

Similar Documents

Publication Publication Date Title
CN108351405B (en) Circuit and method for determining chirp signal linearity and phase noise of FMCW radar
US9134355B2 (en) Apparatus for very high speed adaptive spectrum analysis
US8525509B2 (en) Low cost simplified spectrum analyzer for magnetic head/media tester
US5952834A (en) Low noise signal synthesizer and phase noise measurement system
GB2416620A (en) Electronically driving a quadrupole mass spectrometer
JP2007532028A (en) Improved RF power control device for RF plasma application
JP2005518686A (en) Intermodulation product cancellation circuit
WO2013003301A1 (en) Method for detecting leakage in digitally modulated systems
CN104410469B (en) Calibration method for tracking preselector based on built-in noise source
EP0877945B1 (en) A receiver for spectrum analysis
CN107479089B (en) A kind of power detector
US20120259571A1 (en) Iq calibration method of test device for wireless communication system such as dvb-h system or like, device, and test device manufacturing method
US4149122A (en) Wideband tracking generator for harmonic mixing receivers
CN112073015A (en) Automatic gain feedback control method and device
US20090247098A1 (en) System and Method for Autoranging in Test Apparatus
CN106353594B (en) A kind of fast multiresolution frequency spectrum analysis system and method
EP1305643B1 (en) Signal measurement
CN113422604B (en) Frequency synthesizer
US10411816B2 (en) Method for searching a spur in a signal received and device for searching a spur in a signal received
CN104753611B (en) Frequency conversion system and method based on frequency spectrograph
Power et al. The design and initial testing of a beam phase and energy measurement for LEDA
Millenaar et al. SSSM system design considerations
KR100670128B1 (en) Electromagnetic Analyzer with filter design and filter measure function
CN114441890A (en) Network analyzer with ultra-wideband detection gain control
JP2009510432A (en) System and method for automatic range adjustment in a test apparatus

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination