CN207780123U - A kind of low-frequency noise measuring device - Google Patents
A kind of low-frequency noise measuring device Download PDFInfo
- Publication number
- CN207780123U CN207780123U CN201820857228.6U CN201820857228U CN207780123U CN 207780123 U CN207780123 U CN 207780123U CN 201820857228 U CN201820857228 U CN 201820857228U CN 207780123 U CN207780123 U CN 207780123U
- Authority
- CN
- China
- Prior art keywords
- amplifier
- resistance
- low
- connect
- pins
- 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.)
- Active
Links
Landscapes
- Testing Electric Properties And Detecting Electric Faults (AREA)
Abstract
The utility model discloses a kind of low-frequency noise measuring device, including sequentially connected high-gain preamplifier and low gain postfilter, the input terminal of the high-gain preamplifier is connect by SMA connectors with coaxial input cable, the output end of the low gain postfilter is connect by SMA connectors with coaxial output cable, the coaxial input cable is used to transmit input signal to the noise-measuring system, and the coaxial output cable is used for transmission the output signal of the noise-measuring system.The utility model uses the architecture design of high-gain amplifier prime and low gain filter rear class, is capable of the noise level of effective control and measure device itself, to keep noise testing more accurate.
Description
Technical field
The utility model is related to noise testing fields, and in particular to a kind of low-frequency noise measuring device.
Background technology
In the electronic device, the signal except signal of concern is referred to as noise by us, is made an uproar in each frequency band
The presence of sound, such as high-frequency noise, mid-frequency noise, low-frequency noise.According to the difference of equipment, need the noise paid close attention to also different,
For example, in a wireless communication system, we are concerned with hundreds of MHz to the signal of number GHz, so in hundreds of MHz to number GHz bands
Noise in wide scope just influences whether communication quality, and for the precision equipment for being operated under DC state, then more hold
It is vulnerable to the influence of low-frequency noise, because it will not respond high-frequency noise, high-frequency noise does not influence it.
Low-frequency noise in existing sophisticated electronics refers to the noise in 0.1Hz~10Hz this bandwidth, low-frequency noise
It is easy to be superimposed upon on useful signal, and then changes the true amplitude of useful signal, to reduce the precision of sophisticated electronics.It is bright
The output noise size of true sophisticated electronics, is the necessary item whether clear sophisticated electronics can reach higher precision
Part, it is therefore desirable to which suitable device and method measure this low-frequency noise, and existing noise-measuring system is filled due to measuring
The noise level of itself is set, lower-cut-off frequency can only accomplish 2Hz or higher, therefore always have significant portion frequency when measuring
The noise testing of section less than, so test result and real noise level be there are bigger difference, accurate evaluation of having no way
The noise level of Devices to test.
Utility model content
In view of this, the application provides a kind of low-frequency noise measuring device, using high-gain amplifier prime and low gain
The architecture design of filter rear class is capable of the noise level of effective control and measure device itself, to keep noise testing more smart
Really.In order to solve the above technical problems, the technical scheme that the utility model is provided is as follows：
The application provides a kind of low-frequency noise measuring device, including sequentially connected high-gain preamplifier and low gain
The input terminal of postfilter, the high-gain preamplifier is connect by SMA connectors with coaxial input cable, described low
The output end of gain postfilter is connect by SMA connectors with coaxial output cable, and the coaxial input cable is for giving
The noise-measuring system transmits input signal, and the coaxial output cable is used for transmission the output letter of the noise-measuring system
Number.
Further, the circuit structure of the high-gain preamplifier includes the first amplifier；
For the in-phase input end of first amplifier by first resistor and the first capacitance connection, the first resistor is opposite
Connect input terminal of the other end of first capacitance as the high-gain preamplifier, the first resistor and described the
One end of one capacitance connection is grounded by second resistance；
The inverting input of first amplifier is connect with one end of 3rd resistor and the 4th resistance simultaneously, the third
The other end of resistance is grounded, the other end of the 4th resistance simultaneously with the output end of first amplifier and the 5th resistance
One end connects, the output end and the low gain postposition of the other end of the 5th resistance as the high-gain preamplifier
The input terminal of filter connects.
Further, the low gain postfilter includes the 0.1Hz high-pass filters being connected with each other and 10Hz low passes
Filter, the input terminal of the 0.1Hz high-pass filters are connect with the output end of the high-gain preamplifier, the 10Hz
The output end of low-pass filter is the output end of low gain postfilter.
Further, the circuit structure of the 0.1Hz high-pass filters includes the second amplification of model OPA827AID
Device；
No. three pins of second amplifier by third capacitance and the second capacitance connection, second capacitance it is another
The input terminal as the 0.1Hz high-pass filters, No. three pins of second amplifier is held to be connect by the 6th resistance
Ground；
No. two pins of second amplifier are connect with one end of the 7th resistance and the 8th resistance simultaneously, the 7th electricity
The other end of resistance is grounded, and the other end of the 8th resistance is connect with No. six pins of second amplifier；
No. six pins of second amplifier are connect by the 9th resistance with the tenth resistance, and the tenth resistance is opposite to be connected
The other end for connecing the 9th resistance is connected on the circuit that second capacitance is connected with the third capacitance, second amplifier
Output end of No. six pins as the 0.1Hz high-pass filters；
No. four pins and No. seven pins of second amplifier are connected separately with -10V power supplys and+10V power supplys.
Further, the 10Hz low-pass filters are fourth order low-pass filter.
Further, the circuit structure of the 10Hz low-pass filters includes the third amplification that model is OPA827AID
Device and the 4th amplifier；
No. two pins of the third amplifier are connect by twelfth resistor with eleventh resistor, the eleventh resistor
Input terminal of the other end as the 10Hz low-pass filters, the eleventh resistor connect with the twelfth resistor one
End is also connect with one end of the 4th capacitance and thirteenth resistor simultaneously, the other end ground connection of the 4th capacitance, and the described 13rd
The other end of resistance is connect with No. six pins of the third amplifier, and No. two pins of the third amplifier also pass through the 4th
Capacitance is connect with No. six pins；
No. two pins of the 4th amplifier are connect by the 15th resistance with the 14th resistance, the 14th resistance
The other end connect with No. six pins of third amplifier, one end that the 14th resistance is connect with the 15th resistance is also
It is connect simultaneously with one end of the 6th capacitance and the 16th resistance, the other end ground connection of the 6th capacitance, the 16th resistance
The other end connect with No. six pins of third amplifier, the 4th amplifier No. two pins also by the 7th capacitance with it is described
No. six pins of the 4th amplifier connect, the output of No. six pins of the 4th amplifier as the 10Hz low-pass filters
End；
No. four pins of the third amplifier and the 4th amplifier are respectively connected with -10V power supplys, the third amplifier and
No. seven pins of the 4th amplifier are respectively connected with+10V power supplys.
After the utility model provides body low-frequency noise measuring device using high-gain amplifier prime and low gain filter
The architecture design of grade is capable of the noise level of effective control and measure device itself, to keep noise testing more accurate, using four
Rank low-pass filter can be that filter edge is more precipitous, and frequency band energy is divided more acurrate, is capable of providing more accurate survey
Measure result.
Description of the drawings
Fig. 1 is the electrical block diagram that embodiment provides.
Reference numeral：The first amplifiers of A1-, the second amplifiers of A2-, A3-third amplifier, the 4th amplifiers of A4-,
The 4th resistance of R1-first resistor, R2-second resistance, R3-3rd resistor, R4-, the 5th resistance of R5-, the 6th electricity of R6-
Resistance, the 7th resistance of R7-, the 8th resistance of R8-, the 9th resistance of R9-, the tenth resistance of R10-, R11-eleventh resistor, R12-
Twelfth resistor, the 14th resistance of R13-thirteenth resistor, R14-, the 15th resistance of R15-, the 16th resistance of R16-,
The first capacitances of C1-, the second capacitances of C2-, C3-third capacitance, the 4th capacitances of C4-, the 5th capacitances of C5-, the 6th electricity of C6-
Hold, the 7th capacitances of C7-.
Specific implementation mode
In order to make those skilled in the art more fully understand the technical solution of the utility model, below in conjunction with the accompanying drawings and have
The utility model is described in further detail for body embodiment.
Embodiment
The present embodiment provides a kind of low-frequency noise measuring devices, including sequentially connected high-gain preamplifier and low increasing
The input terminal of beneficial postfilter, the high-gain preamplifier is connect by SMA connectors with coaxial input cable, described
The output end of low gain postfilter is connect by SMA connectors with coaxial output cable, and the coaxial input cable is used for
Input signal is transmitted to the noise-measuring system, the coaxial output cable is used for transmission the output of the noise-measuring system
Signal.
What needs to be explained here is that the present embodiment transmits signal using SMA connectors and coaxial cable, can effectively reduce
The interference of external noise, when the present embodiment is embodied, measured signal is typically uV ranks, uses oscillograph (minimum point
Resolution is mV ranks) it can not observe this kind of signal, it is therefore desirable to input signal (measured signal) is amplified, the present embodiment
In high-gain preamplifier amplification factor be 1000, input signal is output to oscillograph after amplification and filtering and is shown
Show, in addition, the present embodiment only needs an ordinary oscilloscope that can complete noise testing, it is cost-effective.
Specifically, as shown in Figure 1, in the present embodiment, the circuit structure of high-gain preamplifier includes the first amplifier
A1；
The in-phase input end of first amplifier A1 is connect by first resistor R1 with the first capacitance C1, and first resistor R1 is opposite
Connect input terminal of the other end of the first capacitance C1 as the high-gain preamplifier, first resistor R1 and first electricity
The one end for holding C1 connections is grounded by second resistance R2；
The inverting input of first amplifier A1 is connect with one end of 3rd resistor R3 and the 4th resistance R4 simultaneously, and described the
The other end of three resistance R3 is grounded, the other end of the 4th resistance R4 simultaneously with the output end of the first amplifier A1 and the
One end of five resistance R5 connects, the output end and institute of the other end of the 5th resistance R5 as the high-gain preamplifier
State the input terminal connection of low gain postfilter.
The first amplifier A1 in the present embodiment can select the amplifier of model OPA2188AID.
Specifically, in the present embodiment, the low gain postfilter include be connected with each other 0.1Hz high-pass filters and
10Hz low-pass filters, the input terminal of the 0.1Hz high-pass filters are connect with the output end of the high-gain preamplifier,
The output end of the 10Hz low-pass filters is the output end of low gain postfilter.
It should be noted that the high-pass filter in the present embodiment can select the fertile hereby type of Bart, hereby filtered since Bart is fertile
Wave device has extraordinary flatness in passband, can improve measurement accuracy, and the high-pass filter in the present embodiment is used for being arranged
Test lower frequency limit.
Specifically, the circuit structure of the 0.1Hz high-pass filters includes the second amplifier of model OPA827AID
A2；
No. three pins of second amplifier A2 are connect by third capacitance C3 with the second capacitance C2, the second capacitance C2's
No. three pins of input terminal of the other end as the 0.1Hz high-pass filters, the second amplifier A2 pass through the 6th
Resistance R6 ground connection；
No. two pins of second amplifier A2 are connect with one end of the 7th resistance R7 and the 8th resistance R8 simultaneously, and the described 7th
The other end of resistance R7 is grounded, and the other end of the 8th resistance R8 is connect with No. six pins of the second amplifier A2；
No. six pins of second amplifier A2 are connect by the 9th resistance R9 with the tenth resistance R10, the tenth resistance R10
The other end of the 9th resistance R9 of opposite connection is connected on the circuit that the second capacitance C2 is connected with the third capacitance C3, institute
State output end of No. six pins of the second amplifier A2 as the 0.1Hz high-pass filters；
No. four pins and No. seven pins of second amplifier A2 are connected separately with -10V power supplys and+10V power supplys.
Preferably, the 10Hz low-pass filters are fourth order low-pass filter.
Specifically, the circuit structure of the 10Hz low-pass filters includes the third amplifier that model is OPA827AID
A3 and the 4th amplifier A4；
No. two pins of third amplifier A3 are connect by twelfth resistor R12 with eleventh resistor R11, and the described 11st
Input terminal of the other end of resistance R11 as the 10Hz low-pass filters, the eleventh resistor R11 and the 12nd electricity
The one end for hindering R12 connections is also connect with one end of the 4th capacitance C4 and thirteenth resistor R13 simultaneously, and the 4th capacitance C4's is another
One end is grounded, and the other end of the thirteenth resistor R13 is connect with No. six pins of the third amplifier A3, and the third is put
No. two pins of big device A3 are also connect by the 4th capacitance with No. six pins；
No. two pins of 4th amplifier A4 are connect by the 15th resistance R15 with the 14th resistance R14, and the described 14th
The other end of resistance R14 is connect with No. six pins of third amplifier A3, the 14th resistance R14 and the 15th resistance
One end of R15 connections is also connect with one end of the 6th capacitance C6 and the 16th resistance R16 simultaneously, and the 6th capacitance C6's is another
End ground connection, the other end of the 16th resistance R16 connect with No. six pins of third amplifier A3, the 4th amplifier A4
No. two pins are also connect by the 7th capacitance C7 with No. six pins of the 4th amplifier A4, and the six of the 4th amplifier A4
Number output end of the pin as the 10Hz low-pass filters；
No. four pins of the third amplifier A3 and the 4th amplifier A4 are respectively connected with -10V power supplys, the third amplification
No. seven pins of device A3 and the 4th amplifier A4 are respectively connected with+10V power supplys.
What needs to be explained here is that the 10Hz low-pass filters in the present embodiment are used for testing upper limiting frequency, the filter
A four-step filter, speed of roll-offing is ten octaves of 80dB/, why select it is so big roll-off, be exactly in order to more
Detach in-band noise and out-of-band noise well.
In the present embodiment, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5,
Six resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, eleventh resistor R11, the 12nd electricity
Resistance R12, thirteenth resistor R13, the 14th resistance R14, the 15th resistance R15 and the 16th resistance R16 can be respectively set to 0
Ω、15.4kΩ、51kΩ、51kΩ、0、634kΩ、1kΩ、9.09kΩ、2MΩ、2MΩ、162kΩ、210kΩ、1.6kΩ、
825k Ω, 412k Ω and 825k Ω, the first capacitance C1, the second capacitance C2, third capacitance C3, the 4th capacitance C4, the 5th capacitance C5,
6th capacitance C6 and the 7th capacitance C7 can be respectively set to 220uF, 1uF, 1uF, 0.1uF, 7.5nF, 7.5nF and 7.5nF.
Above are merely preferred embodiments of the utility model, it is noted that above-mentioned preferred embodiment should not regard
For limitations of the present invention, the scope of protection of the utility model should be subject to claim limited range.For
For those skilled in the art, without departing from the spirit and scope of the utility model, it can also make several
Improvements and modifications, these improvements and modifications also should be regarded as the scope of protection of the utility model.
Claims (6)
1. a kind of low-frequency noise measuring device, which is characterized in that including sequentially connected high-gain preamplifier and low gain
The input terminal of postfilter, the high-gain preamplifier is connect by SMA connectors with coaxial input cable, described low
The output end of gain postfilter is connect by SMA connectors with coaxial output cable, and the coaxial input cable is for giving
The noise-measuring system transmits input signal, and the coaxial output cable is used for transmission the output letter of the noise-measuring system
Number.
2. a kind of low-frequency noise measuring device according to claim 1, which is characterized in that the high-gain preamplifier
Circuit structure include the first amplifier (A1)；
The in-phase input end of first amplifier (A1) is connect by first resistor (R1) with the first capacitance (C1), and described first
Input terminal of the opposite other end for connecting first capacitance (C1) of resistance (R1) as the high-gain preamplifier, it is described
One end that first resistor (R1) is connect with first capacitance (C1) is grounded by second resistance (R2)；
The inverting input of first amplifier (A1) is connect with one end of 3rd resistor (R3) and the 4th resistance (R4) simultaneously,
The other end of the 3rd resistor (R3) is grounded, the other end of the 4th resistance (R4) simultaneously with first amplifier (A1)
Output end and the 5th resistance (R5) one end connection, the other end of the 5th resistance (R5) before the high-gain as putting
The output end of big device is connect with the input terminal of the low gain postfilter.
3. a kind of low-frequency noise measuring device according to claim 1, which is characterized in that the low gain postfilter
0.1Hz high-pass filters including interconnection and 10Hz low-pass filters, the input terminal of the 0.1Hz high-pass filters and institute
The output end connection of high-gain preamplifier is stated, the output end of the 10Hz low-pass filters is low gain postfilter
Output end.
4. a kind of low-frequency noise measuring device according to claim 3, which is characterized in that the 0.1Hz high-pass filters
Circuit structure include model OPA827AID the second amplifier (A2)；
No. three pins of second amplifier (A2) are connect by third capacitance (C3) with the second capacitance (C2), second electricity
Hold input terminal of the other end of (C2) as the 0.1Hz high-pass filters, No. three of second amplifier (A2) are drawn
Foot is grounded by the 6th resistance (R6)；
No. two pins of second amplifier (A2) are connect with one end of the 7th resistance (R7) and the 8th resistance (R8) simultaneously, institute
State the other end ground connection of the 7th resistance (R7), No. six of the other end of the 8th resistance (R8) and second amplifier (A2)
Pin connects；
No. six pins of second amplifier (A2) are connect by the 9th resistance (R9) with the tenth resistance (R10), and the described tenth
The other end of resistance (R10) the 9th resistance (R9) of opposite connection is connected to second capacitance (C2) and the third capacitance (C3)
On connected circuit, the output end of No. six pins of second amplifier (A2) as the 0.1Hz high-pass filters；
No. four pins and No. seven pins of second amplifier (A2) are connected separately with -10V power supplys and+10V power supplys.
5. a kind of low-frequency noise measuring device according to claim 3, which is characterized in that the 10Hz low-pass filters are
Fourth order low-pass filter.
6. a kind of low-frequency noise measuring device according to claim 5, which is characterized in that the 10Hz low-pass filters
Circuit structure includes the third amplifier (A3) and the 4th amplifier (A4) that model is OPA827AID；
No. two pins of the third amplifier (A3) are connect by twelfth resistor (R12) with eleventh resistor (R11), described
Input terminal of the other end of eleventh resistor (R11) as the 10Hz low-pass filters, the eleventh resistor (R11) and institute
It states one end of twelfth resistor (R12) connection also while being connect with one end of the 4th capacitance (C4) and thirteenth resistor (R13), institute
State the other end ground connection of the 4th capacitance (C4), the other end of the thirteenth resistor (R13) and the third amplifier (A3)
No. six pin connections, No. two pins of the third amplifier (A3) are also connect by the 4th capacitance with No. six pins；
No. two pins of the 4th amplifier (A4) are connect by the 15th resistance (R15) with the 14th resistance (R14), described
The other end of 14th resistance (R14) is connect with No. six pins of third amplifier (A3), the 14th resistance (R14) and institute
It states one end of the 15th resistance (R15) connection also while being connect with one end of the 6th capacitance (C6) and the 16th resistance (R16), institute
State the 6th capacitance (C6) the other end ground connection, the other end of the 16th resistance (R16) with No. six of third amplifier (A3)
Pin connects, and No. two pins of the 4th amplifier (A4) of institute also pass through the six of the 7th capacitance (C7) and the 4th amplifier (A4)
The connection of number pin, the output end of No. six pins of the 4th amplifier (A4) as the 10Hz low-pass filters；
No. four pins of the third amplifier (A3) and the 4th amplifier (A4) are respectively connected with -10V power supplys, the third amplification
No. seven pins of device (A3) and the 4th amplifier (A4) are respectively connected with+10V power supplys.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820857228.6U CN207780123U (en) | 2018-06-04 | 2018-06-04 | A kind of low-frequency noise measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820857228.6U CN207780123U (en) | 2018-06-04 | 2018-06-04 | A kind of low-frequency noise measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207780123U true CN207780123U (en) | 2018-08-28 |
Family
ID=63210003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820857228.6U Active CN207780123U (en) | 2018-06-04 | 2018-06-04 | A kind of low-frequency noise measuring device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207780123U (en) |
-
2018
- 2018-06-04 CN CN201820857228.6U patent/CN207780123U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100381829C (en) | Electromagnetic detector for electromagnetic compatible diagnostic test in vehicle | |
| CN107918062B (en) | Wide-frequency-domain transient space electric field measurement system and method | |
| CN111880052A (en) | Hand-held type partial discharge detection device based on bluetooth interconnection terminal cluster | |
| CN206096245U (en) | Two difference formula D dot crosses voltage sensor and monitoring system | |
| CN207780123U (en) | A kind of low-frequency noise measuring device | |
| CN107656226A (en) | HFCT electrical parameter test devices and method of testing based on transmission coefficient | |
| CN207352066U (en) | A kind of signal supervisory instrument | |
| CN206990102U (en) | A kind of strong vibration sensor circuit and signal acquiring system for primary cut-out | |
| CN104101778B (en) | 67GHz coaxial broadband peak power probe | |
| CN209087099U (en) | A kind of RF signal collection and the test probe of signal injection | |
| JPH0394178A (en) | Measuring device for high frequency signal | |
| CN207908626U (en) | A kind of simulation high frequency Partial discharge signal generating means | |
| CN207664985U (en) | Optical-fiber network rate detection circuit | |
| CN113447742B (en) | Wide spectrum/ultra-wide spectrum electromagnetic environment testing system | |
| CN216670093U (en) | Signal isolator and signal test system | |
| CN203563066U (en) | Orthogonal signal based test system for power line carrier channel attenuation | |
| CN206594317U (en) | Hydrophone sensitivity detector and its sound pressure signal collecting mechanism | |
| CN210775815U (en) | Probe for measuring broadband transient magnetic field | |
| CN207573323U (en) | A kind of filtering gain circuit | |
| CN207133352U (en) | A kind of current measuring device and system | |
| CN208015723U (en) | A kind of power wire broadband carrier communication networking test system | |
| Cormack et al. | Picosecond pulse generator using delay lines | |
| CN207113914U (en) | A kind of test device of high frequency low voltage ultrasonic sensor | |
| CN207475533U (en) | A kind of signal source circuit | |
| CN201724993U (en) | Radiation noise testing system for digital gravity metering device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |