CN109861658A - The broadband of Weak absorption, low noise differential amplifier circuit - Google Patents
The broadband of Weak absorption, low noise differential amplifier circuit Download PDFInfo
- Publication number
- CN109861658A CN109861658A CN201910020450.XA CN201910020450A CN109861658A CN 109861658 A CN109861658 A CN 109861658A CN 201910020450 A CN201910020450 A CN 201910020450A CN 109861658 A CN109861658 A CN 109861658A
- Authority
- CN
- China
- Prior art keywords
- resistance
- amplifying circuit
- circuit
- transporting discharging
- integrated transporting
- 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
Links
Abstract
The present invention relates to Technique of Weak Signal Detection, have the shortcomings that frequency band is narrow, noise is high for the detection circuit of sea sensor output small-signal, the present invention is directed to propose the amplifying circuit of a kind of broadband, low noise, this amplifying circuit can carry out effective amplification of nanoscale (nV) small-signal in 0.1Hz-10MHz broad frequency range, and self-noise level is lower.For this reason, the technical scheme adopted by the present invention is that the broadband of Weak absorption, low noise differential amplifier circuit, including three-stage amplifier, first order amplifying circuit uses proportional difference amplifying circuit, and second level amplifying circuit uses high-pass filtering amplifying circuit, and the third level uses scaling circuit；The two-pass DINSAR output of first order amplifier respectively enters same phase, the inverting input terminal of second level amplifier.Present invention is mainly applied to Detection of Weak Signals occasions.
Description
Technical field
The present invention relates to a kind of Technique of Weak Signal Detection, in particular to a kind of broadband of Weak absorption, low noise
Sound differential amplifier circuit, the circuit can effectively amplify electromagnetic type current meter front sensors output ground small-signal,
It is horizontal that background noise in the frequency domain of multiple sensors material can also be measured simultaneously.
Background technique
Currently, electromagnetic type current meter excites field source because it uses earth's magnetic field to be used as in the research and development of ocean current measurement instrument, itself
Equipment need not design emission source, so that front-end probe is more light.It is quicker, convenient relative to other ocean current measurement equipment,
The parameter measurement being suitable under a variety of marine environment.Such as document: Zhang Qisheng was " Chinese Journal of Geophysics " 2013 the 56th (11)
The 3699-3707 pages of article " jettisoning the development of formula ocean current electric field profile instrument " delivered is rolled up, since is produced from seawater movement cutting earth magnetism place
Raw electric field amplitude is very faint, and precision signal caused by 1cm/s current meter is to receive to lie prostrate grade (nV), and noise should not exceed
50nV.General preamplifier, which can not achieve, carries out under different frequency without amplifier noise interference expected small-signal
Effectively amplification.Therefore, it is necessary to make a kind of broadband of Weak absorption, low noise amplifier circuit.
Summary of the invention
In order to overcome the deficiencies of the prior art, that there are frequency bands is narrow for the detection circuit of sea sensor output small-signal,
The high disadvantage of noise, the present invention is directed to propose the amplifying circuit of a kind of broadband, low noise, this amplifying circuit is in 0.1Hz-
Effective amplification of nanoscale (nV) small-signal can be carried out in 10MHz broad frequency range, and self-noise level is lower.For
This, the technical solution adopted by the present invention is that, the broadband of Weak absorption, low noise differential amplifier circuit, including three-level are put
Big circuit, first order amplifying circuit use proportional difference amplifying circuit, and second level amplifying circuit uses high-pass filtering amplifying circuit,
The third level uses scaling circuit；First order amplifier two-pass DINSAR output respectively enter second level amplifier same phase,
Inverting input terminal.
Specifically, first order amplifying circuit use proportional difference amplifying circuit, including first resistor (R1), second resistance,
3rd resistor, the first integrated transporting discharging and the second integrated transporting discharging, second resistance, 3rd resistor are respectively as the first, second integrated fortune
The same phase put, inverting feedback resistance, the inverting input terminal of the first integrated transporting discharging are the input terminal of first order amplifying circuit, the first collection
The inverting input terminal of the second integrated transporting discharging, the same phase of the second integrated transporting discharging are connected to through 3rd resistor at the non-inverting input terminal of amplifier
Input end grounding；The differential amplification multiple of first order amplifying circuit is 1+2R2/R1, and R1, R2 are respectively the first, second resistance
Resistance value；Second level filter amplification circuit includes the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, first capacitor, second
Capacitor and third integrated transporting discharging, the output of the first integrated transporting discharging are successively connected to the integrated fortune of third through first capacitor, the 4th resistance
Inverting input terminal is put, the output of the second integrated transporting discharging is successively connected to the same phase of third integrated transporting discharging through the second capacitor, the 5th resistance
Input terminal, the 6th resistance are third integrated transporting discharging inverting feedback resistance, and the 7th resistance is connected across third integrated transporting discharging homophase input
Between end and ground, the differential amplification multiple of second level filter amplification circuit is R7/R5, and R7, R5 are the 7th resistance, the 5th electricity respectively
Hinder resistance value.
The high-pass filter calculation formula of second level filter amplification circuit is:
The calculation formula of cutoff frequency fc is:
C1, C2 are respectively the capacitance of first capacitor, the second capacitor.
The circuit noise level mainly determines by the noise of first order differential amplifier circuit, its calculation formula is:
WhereinFor the voltage noise power spectral density of the first integrated transporting discharging,For the electricity of the second integrated transporting discharging
Noise power spectral density is pressed,For the equivalent voltage power spectral density of first resistor,For the equivalent electricity of second resistance
Power spectral density is pressed,For the equivalent voltage power spectral density of 3rd resistor.
The features of the present invention and beneficial effect are:
The performance test results and advantage of the present invention are as follows:
1, amplification factor spectral performance is tested: this broadband amplifying circuit is times magnification in 10Hz-10MHz in frequency range
The value of number G is 1210 (about 61.66dB), and in 0.1Hz-10Hz frequency band, amplification factor is also maintained at 700 times (about 56.90dB)
More than.Its filtering performance is very good, interferes amplification factor (as shown in Figure 2) without other factors.
2, the total input noise test of amplifying circuit: in 1Hz-10MHz frequency range, noise by low frequency 1/f noise and
High frequency white noise composition.1/f noise power spectral density at 1Hz is 14.32 × 10-18V2/Hz, measurement error is 2.15 ×
10-18V2/Hz；Power Spectrum of White Noise density within the scope of 10Hz-10MHz is 3.04 × 10-18V2/Hz, and measurement error is
0.46×10-18V2/Hz；In view of error amount, noise measurement is all satisfied in circuit noise design value (as shown in Figure 3).
3, this broadband, low noise differential amplifier circuit, a variety of frequencies that electromagnetic type current meter front sensors can be exported
Volt grade (nV) small-signal of receiving of rate is effectively amplified, while can also measure background noise in multiple sensors material frequency domain
It is horizontal.The present invention provides trivector database building methods in a kind of ray trace, pass through simplified three-dimensional CAD modeling side
Method establishes three-dimensional scene models and database, and it is visible about the three-dimensional of scene then to establish viewpoint using modified perspective projection
Metadatabase is capable of the biggish dough sheet and the quantity split for reducing and participating in that ray trace calculates, so be effectively reduced ray with
The computation complexity of track channel modeling method.
Detailed description of the invention:
Fig. 1 is circuit diagram of the invention.
Fig. 2 is circuit amplification factor spectral performance test chart in kind.
Fig. 3 is the total input noise test chart of circuit in kind.
Specific embodiment
The purpose of the invention is achieved by the following technical solution: a kind of broadband of Weak absorption, low noise difference
Amplifying circuit, including three-stage amplifier, the first order and third level amplifying circuit are all made of proportional difference amplifying circuit, and described
Second level differential amplifier circuit uses high-pass filtering differential amplifier circuit.Wherein: first order use ratio differential amplifier circuit, including
First resistor (R1), second resistance (R2), 3rd resistor (R3), the first integrated transporting discharging (AD797-11) and the second integrated transporting discharging
(AD797-12)；The differential amplification multiple of first order amplifying circuit is (1+2R2/R1)；Second resistance (R2) and 3rd resistor
It (R3) is the build-out resistor for being symmetrically distributed in the positive terminal of integrated transporting discharging, the resistance value of two resistance is equal, this purpose is elimination pair
The interference of differential output voltage.In order to guarantee the amplification factor of every grade of amplifying circuit close to 10 times, second resistance (R2) and
The resistance value of three resistance (R3) should be set as 500 Ω, and first resistor (R1) resistance value is set as 100 Ω；
Second level filter amplification circuit, including the 4th resistance (R4), the 5th resistance (R5), the 6th resistance (R6), the 7th electricity
Hinder (R7), first capacitor (C1), the second capacitor (C2) and third integrated transporting discharging (AD797-21)；Second level filter amplification circuit
Differential amplification multiple is (R7/R5), and high-pass filter calculation formula is:
The calculation formula of the cutoff frequency fc of this high-pass filter is:
The cutoff frequency of this amplifying circuit is 0.8 0Hz, according to cutoff frequency calculation formula, first capacitor (C1), second
What capacitor (C2) used is capacitance for the aluminium electrolutic capacitor of 100 μ F；It can be calculated the 4th resistance (R4) and the 5th electricity
The resistance value of resistance (R5) is disposed as 2K Ω.In order to match with amplification factor, the resistance value of the 4th resistance (R4) is set as 2K Ω, and the 5th
The resistance value of resistance (R5) is set as 2K Ω, and the resistance value of the 6th resistance (R6) is set as the resistance value setting of 20K Ω, the 7th resistance (R7)
For 20K Ω；
Third level differential amplifier circuit uses scaling circuit, including the 8th resistance (R8), the 9th resistance (R9) and the
Four integrated transporting dischargings (AD797-31)；The differential amplification multiple of third amplifying circuit is (1+R9/R8)；The resistance value of 8th resistance (R8)
It is set as 1K Ω, the resistance value of the 9th resistance (R9) is set as 10K Ω, this purpose is to guarantee amplification factor close to 10；
The value of the total differential amplification multiple G of the amplifying circuit is 1210, and the amplification factor is equal to first order amplification electricity
The superposition that is multiplied on road, second level amplifying circuit and third level amplifying circuit amplification factors at different levels, its calculation formula is:
The circuit noise level mainly determines by the noise of first order differential amplifier circuit, its calculation formula is:
WhereinFor the voltage noise power spectral density of the first integrated transporting discharging (AD797-11),For the second collection
At the voltage noise power spectral density of amplifier (AD797-12),For the equivalent voltage power spectrum of first resistor (R1)
Degree,For the equivalent voltage power spectral density of second resistance (R2),For the equivalent voltage power of 3rd resistor (R3)
Spectrum density.
The amplifying circuit is within the scope of 10Hz-10MHz in frequency band, and noise is mainly by first resistor (R1), second resistance
(R2) it is determined with the white noise of 3rd resistor (R3).Amplifying circuit noise when less than 10Hz is mainly by the first integrated transporting discharging
(AD797-11) it is determined with the low frequency 1/f noise of the second integrated transporting discharging (AD797-12).
The integrated transporting discharging be broadband, high-accuracy, Low Drift Temperature, low noise bipolar field-effect tube operational amplifier
AD797, in 100Hz-10MHz frequency range, Power Spectrum of White Noise density is 8.10 × 10-19V2/Hz, the 1/f at 1Hz
Noise power spectral density is 6.76 × 10-19V2/Hz；The resistance is close tolerance seal metal film fixed resister；It is described
Capacitor is aluminium electrolutic capacitor.
The working principle of the invention:, can root due to amplifier, resistor and the presence of capacitor element in amplifying circuit
According to the frequency of input signal, the amplification factor of circuit is influenced.Simultaneously because there are noise, the overall noises of circuit for electronic device itself
Equal to the superposition of the noise of each device.The major way of circuit design is using symmetrical multi-level differential amplifying circuit, as far as possible
Reduce influence of the individual devices to circuit.In addition broadband, the integrated transporting discharging chip of low noise are used, in conjunction with every grade of amplification factor
It is approximately equal to 10 three-stage amplifier, to guarantee that circuit reaches 103 times or more in the amplification factor of broad frequency band.Circuit design
Two identical symmetrical capacitors of middle addition, eliminate input terminal DC voltage to amplifying circuit and the filtering to low frequency signal
Interference.The present invention includes three-stage amplifier, and the first order and third level amplifying circuit are all made of proportional difference amplifying circuit, the
Second amplifying circuit uses high-pass filtering amplifying circuit.First order amplifying circuit uses proportional difference amplifying circuit, including first
Resistance (R1), second resistance (R2), 3rd resistor (R3), the first integrated transporting discharging (AD797-11) and the second integrated transporting discharging
(AD797-12)；The differential amplification multiple of first order amplifying circuit is (1+2R2/R1).Second level filter amplification circuit, including the
Four resistance (R4), the 5th resistance (R5), the 6th resistance (R6), the 7th resistance (R7), first capacitor (C1), the second capacitor (C2) and
Third integrated transporting discharging (AD797-21)；The differential amplification multiple of second level filter amplification circuit is (R7/R5), high-pass filter
Cutoff frequency is 0.79Hz.Third level differential amplifier circuit uses scaling circuit, including the 8th resistance (R8), the 9th resistance
(R9) and the 4th integrated transporting discharging (AD797-31)；The differential amplification multiple of third amplifying circuit is (1+R9/R8).
It is right with reference to the accompanying drawings and embodiments in order to which the purpose of the present invention, timely scheme and advantage is more clearly understood
The present invention is described in further detail, and embodiments of the present invention are not limited thereto.
As shown in Figure 1, the broadband of Weak absorption of the invention, low noise differential amplifier circuit, including three-level are put
Big circuit, the first order and third level amplifying circuit are all made of proportional difference amplifying circuit, and the second level differential amplifier circuit is adopted
Use filter amplification circuit.
In this amplifying circuit, the differential amplification multiple of first order amplifying circuit is (1+2R2/R1), second level filter and amplification
The differential amplification multiple of circuit is (R7/R5), and the differential amplification multiple of third amplifying circuit is (1+R9/R8), wherein the first electricity
Resistance (R1) resistance value is set as 100 Ω, and second resistance (R2) and 3rd resistor (R3) are the positive terminals for being symmetrically distributed in integrated transporting discharging
Build-out resistor, the resistance value of two resistance is equal, this purpose is the interference eliminated to differential output voltage.In order to guarantee that every grade puts
For the amplification factor of big circuit close to 10 times, the resistance value of second resistance (R2) and 3rd resistor (R3) is 500 Ω, the 5th resistance
(R5) resistance value is 2K Ω, the resistance value of the 7th resistance (R7) is set as 20K Ω, and the resistance value of the 8th resistance (R8) is set as 1K Ω,
The resistance value of 9th resistance (R9) is set as 10K Ω.The total differential amplification multiple of circuit is the superposition of three-stage amplifier amplification factor,
The total magnification is 1210, its calculation formula is:
The Filtering Formula of second level high-pass filtering amplifying circuit are as follows:
, in formula, first capacitor (C1) and the second capacitor (C2) choose the aluminium electrolutic capacitor of 100 μ F.In order to match compared with
It is 2K Ω that low cutoff frequency fc, the 4th resistance (R4) and the 5th resistance (R5), which choose resistance value,.
It is calculated according to cutoff frequency calculation formula, the cutoff frequency fc of this amplifying circuit is 0.80Hz, the cutoff frequency
The calculation formula of rate are as follows:
As shown in Fig. 2, amplifying circuit of the invention is connected to bias voltage source, the frequency sweep that will be generated by signal generator
Signal is inputted by input terminal.It is 2mV that setting signal generator, which exports amplitude, and swept-frequency signal range is 0.1Hz-10MHz.Pass through letter
The signal that number output end obtains is shown: amplifying circuit of the invention is in the value that frequency range is amplification factor G in 10Hz-10MHz
For 1210 (about 61.66dB), in 0.1Hz-10Hz frequency band, amplification differential amplification multiple is also maintained at 700 times or more (about
56.90dB).Its filtering performance is very good, interferes amplification factor without other factors.
Amplifying circuit noise level of the invention mainly determines by the noise of first order differential amplifier circuit, calculation formula
Are as follows:
In formula,For the voltage noise power spectral density of the first integrated transporting discharging (AD797-11),It is second
The voltage noise power spectral density of integrated transporting discharging (AD797-12),For the equivalent voltage power spectrum of first resistor (R1)
Degree,For the equivalent voltage power spectral density of second resistance (R2),For the equivalent voltage power of 3rd resistor (R3)
Spectrum density.Amplifying circuit of the invention is in 10Hz-10MHz frequency band, and noise is mainly by first resistor (R1), second resistance
(R2) it is determined with the white noise of 3rd resistor (R3).Amplifying circuit noise when less than 10Hz is mainly by the first integrated transporting discharging
(AD797-11) it is determined with the low frequency 1/f noise of the second integrated transporting discharging (AD797-12).
As shown in figure 3, amplifying circuit of the invention is connected to bias voltage source, in order to avoid other noise jammings, letter
Number input end grounding carries out output voltage noise power of the circuit in 1Hz-10MHz frequency range using spectrum analyzer
Test, the waveform obtained after testing again divided by the amplification factor in 1Hz-10MHz frequency band square to obtain amplifying circuit total
Input noise waveform.
It should be understood that embodiment of the present invention are not limited by the above embodiments, it can be according to the above description
It is improved or converted, and all these changes and transformation should all belong to the protection domain of appended claims of the present invention.
Claims (3)
1. a kind of broadband of Weak absorption, low noise differential amplifier circuit, characterized in that including three-stage amplifier,
First order amplifying circuit uses proportional difference amplifying circuit, and second level amplifying circuit uses high-pass filtering amplifying circuit, the third level
Using scaling circuit；Same phase, the reverse phase that the two-pass DINSAR output of first order amplifier respectively enters second level amplifier are defeated
Enter end.
2. the broadband of Weak absorption as described in claim 1, low noise differential amplifier circuit, characterized in that specific
Ground, first order amplifying circuit use proportional difference amplifying circuit, including first resistor, second resistance, 3rd resistor, first integrated
Amplifier and the second integrated transporting discharging, second resistance, 3rd resistor are respectively as the same phase of the first, second integrated transporting discharging, inverting feedback
Resistance, the inverting input terminal of the first integrated transporting discharging are the input terminal of first order amplifying circuit, the homophase input of the first integrated transporting discharging
End is connected to the inverting input terminal of the second integrated transporting discharging, the non-inverting input terminal ground connection of the second integrated transporting discharging through 3rd resistor；First
The differential amplification multiple of grade amplifying circuit is 1+2R2/R1, and R1, R2 are respectively the resistance value of the first, second resistance；Second level filtering
Amplifying circuit includes the integrated fortune of the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, first capacitor, the second capacitor and third
It puts, the output of the first integrated transporting discharging is successively connected to third integrated transporting discharging inverting input terminal through first capacitor, the 4th resistance, and second
The output of integrated transporting discharging is successively connected to third integrated transporting discharging non-inverting input terminal through the second capacitor, the 5th resistance, and the 6th resistance is
Third integrated transporting discharging inverting feedback resistance, the 7th resistance are connected across between third integrated transporting discharging non-inverting input terminal and ground, the second level
The differential amplification multiple of filter amplification circuit is R7/R5, and R7, R5 are the 7th resistance, the 5th resistance respectively.
3. the broadband of Weak absorption as described in claim 1, low noise differential amplifier circuit, characterized in that second
The high-pass filter calculation formula of grade filter amplification circuit is:
The calculation formula of cutoff frequency fc is:
C1, C2 are respectively the capacitance of first capacitor, the second capacitor.
The circuit noise level mainly determines by the noise of first order differential amplifier circuit, its calculation formula is:
WhereinFor the voltage noise power spectral density of the first integrated transporting discharging,Voltage for the second integrated transporting discharging is made an uproar
Power sound spectrum density,For the equivalent voltage power spectral density of first resistor,For the equivalent voltage function of second resistance
Rate spectrum density,For the equivalent voltage power spectral density of 3rd resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910020450.XA CN109861658A (en) | 2019-01-09 | 2019-01-09 | The broadband of Weak absorption, low noise differential amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910020450.XA CN109861658A (en) | 2019-01-09 | 2019-01-09 | The broadband of Weak absorption, low noise differential amplifier circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109861658A true CN109861658A (en) | 2019-06-07 |
Family
ID=66894319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910020450.XA Pending CN109861658A (en) | 2019-01-09 | 2019-01-09 | The broadband of Weak absorption, low noise differential amplifier circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109861658A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110806522A (en) * | 2019-11-12 | 2020-02-18 | 天津津航计算技术研究所 | Arc signal detection conditioning circuit |
| CN112698251A (en) * | 2020-11-12 | 2021-04-23 | 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室）） | Magnetic field passive probe and magnetic field detection device |
| CN115235514A (en) * | 2022-09-26 | 2022-10-25 | 天津大学 | Signal processing method, device and system for angular vibration sensor |
| CN116582106A (en) * | 2023-05-22 | 2023-08-11 | 青岛智腾微电子有限公司 | Low-pass filter circuit capable of adjusting stop band depth |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104320092A (en) * | 2014-11-18 | 2015-01-28 | 国家海洋技术中心 | Wideband and low-noise differential application circuit for measuring weak signal |
| CN204156823U (en) * | 2014-11-18 | 2015-02-11 | 国家海洋技术中心 | A kind of broadband low noise differential amplifier circuit of Weak absorption |
| CN109150123A (en) * | 2018-09-28 | 2019-01-04 | 佛山市顺德区中山大学研究院 | A kind of small-signal pre-amplification circuit of high-gain |
-
2019
- 2019-01-09 CN CN201910020450.XA patent/CN109861658A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104320092A (en) * | 2014-11-18 | 2015-01-28 | 国家海洋技术中心 | Wideband and low-noise differential application circuit for measuring weak signal |
| CN204156823U (en) * | 2014-11-18 | 2015-02-11 | 国家海洋技术中心 | A kind of broadband low noise differential amplifier circuit of Weak absorption |
| CN109150123A (en) * | 2018-09-28 | 2019-01-04 | 佛山市顺德区中山大学研究院 | A kind of small-signal pre-amplification circuit of high-gain |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110806522A (en) * | 2019-11-12 | 2020-02-18 | 天津津航计算技术研究所 | Arc signal detection conditioning circuit |
| CN112698251A (en) * | 2020-11-12 | 2021-04-23 | 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室）） | Magnetic field passive probe and magnetic field detection device |
| CN112698251B (en) * | 2020-11-12 | 2023-08-04 | 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室）） | Magnetic field passive probe and magnetic field detection device |
| CN115235514A (en) * | 2022-09-26 | 2022-10-25 | 天津大学 | Signal processing method, device and system for angular vibration sensor |
| CN115235514B (en) * | 2022-09-26 | 2023-02-03 | 天津大学 | Signal processing method, device and system for angular vibration sensor |
| CN116582106A (en) * | 2023-05-22 | 2023-08-11 | 青岛智腾微电子有限公司 | Low-pass filter circuit capable of adjusting stop band depth |
| CN116582106B (en) * | 2023-05-22 | 2023-10-27 | 青岛智腾微电子有限公司 | Low-pass filter circuit capable of adjusting stop band depth |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109861658A (en) | The broadband of Weak absorption, low noise differential amplifier circuit | |
| CN104320092B (en) | A kind of broadband low noise differential amplifier circuit of Weak absorption | |
| US9207198B2 (en) | Electrical tomography apparatus and method and current driver | |
| CN102944765B (en) | Low frequency magnetic sensor background noise measuring method | |
| CN101663589A (en) | Measuring instrument for a resistive electric leakage current | |
| CN101251390A (en) | Apparatus for detecting weak signal based on time-frequency transformation | |
| CN106855540B (en) | Method and system for testing sound insulation quantity of sound insulation cover of main noise equipment of transformer substation | |
| CN105676261A (en) | System and method for measuring beam flow intensity of particle accelerator | |
| CN107238746A (en) | A kind of micro current circuit tested for dielectric response | |
| CN106483402A (en) | Lock-in amplifier test structure and method | |
| CN101964633B (en) | Lock-in amplifier circuit for detecting terahertz pulse signals | |
| CN101819047B (en) | Device and method for evaluating power supply sensitivity of fiber gyro | |
| CN103529405A (en) | Magnetic stimulation coil having function of monitoring three-dimensional dynamic of high-frequency pulse magnetic field | |
| CN103472493B (en) | A kind of Weak Signal Detecting Circuit for gradiometry | |
| CN106324325A (en) | Methods for remote sensing on initial continuous current of artificially triggered lightning applying low-frequency magnetic field antenna | |
| CN109974799B (en) | Self-adaptive electromagnetic flowmeter polarization noise cancellation system based on feedforward control | |
| CN102928713A (en) | Background noise measuring method of magnetic antennas | |
| CN103954851B (en) | Noise coefficient measuring method and noise coefficient standard device | |
| CN102520375B (en) | Fluxgate magnetometer detection circuit and method for improving accuracy thereof | |
| CN113532492A (en) | Static phase-locked amplifying circuit of fiber Bragg grating displacement output signal | |
| CN204156823U (en) | A kind of broadband low noise differential amplifier circuit of Weak absorption | |
| CN210629467U (en) | Front-end signal conditioning circuit of broadband VLF differential type magnetic rod receiving antenna | |
| CN104062004B (en) | Extremely weak optical signal detecting device and method | |
| CN107764285B (en) | Photoelectric detection assembly power supply rejection ratio test system based on phase-locked amplifier | |
| CN105408757A (en) | Magnetic field detection device |
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 | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20190607 |
|
| WD01 | Invention patent application deemed withdrawn after publication |