CN206725656U - LCR RF impedance testers - Google Patents
LCR RF impedance testers Download PDFInfo
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- CN206725656U CN206725656U CN201720579053.2U CN201720579053U CN206725656U CN 206725656 U CN206725656 U CN 206725656U CN 201720579053 U CN201720579053 U CN 201720579053U CN 206725656 U CN206725656 U CN 206725656U
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Abstract
The utility model discloses a kind of LCR RF impedances tester, including be sequentially connected signal source, attenuator, balun, V/I input switching switch, lower frequency changer circuit, processing circuitry of intermediate frequency, ADC collecting units, FPGA, also include 50 Ω precision resisters R1, test port, 50 Ω precision resisters R1 are connected with balun secondary windings Same Name of Ends, and test port is connected with balun secondary windings different name end；Lower frequency changer circuit includes first passage lower frequency changer circuit, second channel lower frequency changer circuit, inputs switching switch with one of which V/I respectively and is connected as V passages and I passages；V channel signals are the voltage drop on part to be measured, and I channel signals are the electric current on part to be measured, and 50 times of both ratios are the impedance of part to be measured.By the above-mentioned means, the utility model measurement accuracy is high, speed is fast, error is small, measurement frequency scope and impedance ranges are wider, strong antijamming capability.
Description
Technical field
A kind of impedance instrument is the utility model is related to, more particularly to a kind of LCR RF impedances tester.
Background technology
The method that impedance instrument uses at present has self-balancing bridge circuit method, vector network analysis method, I-V methods.Bridge method
Measurement accuracy is high, but needs manual balance adjustment, and its measuring resistance needs manual shift, and regulation, time of measuring are grown repeatedly for measurement,
Thus accordingly there is self-balancing bridge circuit method, it is applied to broadband, wide impedance ranges measure, but is not suitable for high frequency survey
Amount, its measurement frequency scope is 20-110MHz, and measurement frequency is low, the measurement for 100MHz to 3GHz, radio frequency I-V methods have compared with
The ability of good measurement, it is for 3GHz and higher frequency, then more to use Network Analysis Method.
The vector network analyzer of application network analytic approach is by measuring reflectance factor Γ x according to formula Γ x=(Zx-
Zo)/(Zx+Zo) seeks impedance Z x (Zo is generally 50 ohm), is curves of the reflectance factor Γ x with impedance variations as shown in Figure 1, by
Γ x knowable to Fig. 1 are non-linear relations with measurement impedance variations, linearly best when measuring impedance close to 50 ohm, when measurement hinders
Anti- to be deteriorated away from linearity at 50 ohm, now when change in impedance value is very big, reflectance factor may vary less, and influence to measure
Precision.Therefore vector network analyzer can only be to accurately being surveyed close to the impedance of its own characteristic impedance (usual 50 ohm)
Amount, the shortcomings that measurement error is big, measurement impedance ranges are narrower be present.
Therefore need badly and provide a kind of new LCR RF impedances tester to solve the above problems.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of measurement accuracy height, speed soon and measurement frequency scope
And the LCR RF impedance testers that impedance ranges are wider.
In order to solve the above technical problems, the technical scheme that the utility model uses is：A kind of LCR RF impedances are provided
Tester, including the signal source, attenuator, balun, V/I input switchings switch, lower frequency changer circuit, the IF process that are sequentially connected are electric
Road, ADC collecting units, FPGA, in addition to 50 Ω precision resisters R1, test port, 50 Ω precision resisters R1 and balun time
Level Motor Winding Same Name of Ends is connected, and test port is connected with balun secondary windings different name end；
Lower frequency changer circuit include first passage lower frequency changer circuit, second channel lower frequency changer circuit, respectively with one of which V/I
Input switching switch is connected as V passages and I passages；
V channel signals be part to be measured on voltage drop, I channel signals be part to be measured on electric current, 50 times of both ratios
The impedance of part as to be measured.
In one preferred embodiment of the utility model, wide-band width measurement signal is down-converted to fixed intermediate frequency by lower frequency changer circuit
Signal is analyzed and processed, and it includes frequency mixer, local oscillator unit, and local oscillator unit is connected with frequency mixer, and local oscillator unit and mixing
Device by casing altogether.
In one preferred embodiment of the utility model, processing circuitry of intermediate frequency includes amplifier, the wave filter being sequentially connected,
For being amplified to intermediate-freuqncy signal and filtering process.
In one preferred embodiment of the utility model, test port uses 50 Ω precision coaxial connectors, improves height
The measuring accuracy of frequency signal.
Further, the frequency range of radiofrequency signal caused by signal source is 1MHz -3GHz, from far away beyond automatic
The frequency range of bridge balance measurement.
Further, the level of RF signals scope of attenuator output is-40-0dBm.
The beneficial effects of the utility model are：
(1) the utility model overcome adjusted repeatedly using bridge measurement, time of measuring is long, measurement frequency is low lacks
Point, measuring speed is improved, most fast point time of measuring is 0.9ms, realizes fast automatic measurement, its measurement frequency scope
(1MHz -3000MHz) is far superior to bridge method；
(2) the utility model measurement accuracy is better than vector network analyzer, vector network analyzer can only to close to its from
The impedance of body characteristic impedance (usual 50 ohm) is accurately measured, the measurable impedance ranges of this tester be 140m Ω-
4.8K Ω, there is the advantages of measurement error is small and measurement impedance ranges are wide；
(3) the utility model is simple using the circuit structure of radio frequency I-V methods measurement impedance, strong antijamming capability.
Brief description of the drawings
The curve map that Γ x change with Zx=Rx+j0 when Fig. 1 is vector network analysis method measurement impedance in the prior art；
Fig. 2 is the theory diagram of the preferred embodiment of the utility model LCR RF impedances tester one；
The mark of each part is as follows in accompanying drawing：1st, signal source, 2, attenuator, 3, balun, 4, V/I input switching switches, 5,
First passage lower frequency changer circuit, 6, second channel lower frequency changer circuit, 7, I passages, 8, V passages, 9, processing circuitry of intermediate frequency, 10, mixed
Frequency device, 11, local oscillator unit, 12, amplifier, 13, wave filter, 14, test port, 15, part to be measured.
Embodiment
Preferred embodiment of the present utility model is described in detail below in conjunction with the accompanying drawings, so that the advantages of the utility model
It can be easier to be readily appreciated by one skilled in the art with feature, it is apparent clear and definite so as to be made to the scope of protection of the utility model
Define.
Referring to Fig. 2, the utility model embodiment includes：
A kind of LCR RF impedances tester, including 50 Ω precision resisters R1, test port 14, the signal being sequentially connected
Source 1, attenuator 2, balun 3, V/I input switchings switch 4, lower frequency changer circuit, processing circuitry of intermediate frequency 9, ADC collecting units, FPGA,
50 Ω precision resisters R1 are connected with the secondary windings Same Name of Ends of balun 3, test port 14 and the secondary windings different name end phase of balun 3
Even, the output end of attenuator 2 is connected with the armature winding Same Name of Ends of balun 3, the armature winding different name end of balun 3 ground connection, down coversion electricity
Road includes first passage lower frequency changer circuit 5, second channel lower frequency changer circuit 6, inputs switching switch 4 with one of which V/I respectively
It is connected as V passages 8 and I passages 7.
Wide-band width measurement signal is down-converted to fixed intermediate frequency signal and analyzed and processed by lower frequency changer circuit, and it includes frequency mixer
10th, local oscillator unit 11, local oscillator unit 11 are connected with frequency mixer 10, and local oscillator unit 11 and frequency mixer 10 by casing altogether.In
Frequency process circuit 9 includes the amplifier 12, the wave filter 13 that are sequentially connected, for being amplified to intermediate-freuqncy signal and filtering process.
Test port 14 uses 50 Ω precision coaxial connector, improves the measuring accuracy of high-frequency signal.
The operation principle of the LCR RF impedances tester is that signal source produces 1MHz -3GHz radiofrequency signal by declining
Subtract after the adjustment amplitude of device 2 meets test level (- 40-0dBm) and be input to test port 14.Signal passes through after entering test port 14
After overcurrent detection balun single-ended transfer difference, two paths of signals is transformed to, two-way radiofrequency signal after lower frequency changer circuit respectively by turning
Be changed to fixed intermediate frequency signal, processing circuitry of intermediate frequency 9 to fixed intermediate frequency signal by carrying out ADC collections after amplifying filtering process,
FPGA carries out analysis calculating to the data collected.The characteristic impedance of measuring circuit and 50 Ω matches, during ensureing high frequency
Optimum precision.Because the balun secondary windings that test electric current flows through is in series with being connected to the part to be measured of test port 14, therefore flow
It is equal to cross R1 and part to be measured 15 electric current, is the Idut in figure, while the Udut voltages in balun 3 can also be surveyed, therefore, V leads to
Road signal Udut represents the voltage drop on part 15 to be measured, and I channel signals Utr represents the electric current of part 15 to be measured.V/I input switchings are opened
4 alternate selection Udut and Utr signals are closed, thus can use same down coversion passage to measure the two vector voltages simultaneously, so as to keep away
Tracking error is exempted from.It can obtain treating the impedance of side part 15 according to formula Zx=50 (Udut/Utr).
The utility model overcome adjusted repeatedly using bridge measurement, the shortcomings that time of measuring is long, measurement frequency is low, carry
Measuring speed has been risen, most fast point time of measuring is 0.9ms, realizes fast automatic measurement, its measurement frequency scope (1MHz-
3000MHz) it is far superior to bridge method；Measurement accuracy is better than vector network analyzer, vector network analyzer can only to close to its
The impedance of self-characteristic impedance (usual 50 ohm) is accurately measured, the measurable impedance ranges of this tester be 140m Ω-
4.8K Ω, there is the advantages of measurement error is small and measurement impedance ranges are wide；The utility model is using the measurement impedance of radio frequency I-V methods
Circuit structure is simple, using be calibrated and compensated for algorithm offset measurement circuit, test fixture and banded cable come added influence, resist dry
It is strong to disturb ability.
Embodiment of the present utility model is the foregoing is only, not thereby limits the scope of the claims of the present utility model, it is every
The equivalent structure or equivalent flow conversion made using the utility model specification and accompanying drawing content, or be directly or indirectly used in
Other related technical areas, similarly it is included in scope of patent protection of the present utility model.
Claims (6)
1. a kind of LCR RF impedances tester, it is characterised in that defeated including the signal source that is sequentially connected, attenuator, balun, V/I
Enter switching switch, lower frequency changer circuit, processing circuitry of intermediate frequency, ADC collecting units, FPGA, in addition to 50 Ω precision resisters R1, survey
Port is tried, 50 Ω precision resisters R1 are connected with balun secondary windings Same Name of Ends, test port and balun secondary windings different name end
It is connected；
Lower frequency changer circuit includes first passage lower frequency changer circuit, second channel lower frequency changer circuit, is inputted respectively with one of which V/I
Switching switch is connected as V passages and I passages；
V channel signals are the voltage drop on part to be measured, and I channel signals are the electric current on part to be measured, and 50 times of both ratios are
The impedance of part to be measured.
2. LCR RF impedances tester according to claim 1, it is characterised in that lower frequency changer circuit includes frequency mixer, sheet
Shake unit, and local oscillator unit is connected with frequency mixer, and local oscillator unit and frequency mixer by casing altogether.
3. LCR RF impedances tester according to claim 1, it is characterised in that processing circuitry of intermediate frequency includes phase successively
Amplifier even, wave filter.
4. LCR RF impedances tester according to claim 1, it is characterised in that test port is accurate same using 50 Ω
Mandrel connector.
5. the LCR RF impedance testers according to any one of Claims 1-4, it is characterised in that penetrated caused by signal source
The frequency range of frequency signal is 1MHz -3GHz.
6. the LCR RF impedance testers according to any one of Claims 1-4, it is characterised in that attenuator output is penetrated
Frequency signal level range is-40-0dBm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720579053.2U CN206725656U (en) | 2017-05-23 | 2017-05-23 | LCR RF impedance testers |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720579053.2U CN206725656U (en) | 2017-05-23 | 2017-05-23 | LCR RF impedance testers |
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| CN206725656U true CN206725656U (en) | 2017-12-08 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109444588A (en) * | 2018-11-15 | 2019-03-08 | 东南大学 | A kind of LCR measuring system based on FPGA+DDS+PLL |
| CN109541315A (en) * | 2018-12-07 | 2019-03-29 | 桂林电子科技大学 | A kind of portable mono port vector impedance analyzer |
| CN113075456A (en) * | 2021-03-18 | 2021-07-06 | 常州同惠电子股份有限公司 | High-precision alternating-current impedance testing system and testing method thereof |
| CN113311240A (en) * | 2021-07-29 | 2021-08-27 | 佛山市联动科技股份有限公司 | Superheterodyne high-frequency impedance test equipment |
| CN113325237A (en) * | 2021-05-21 | 2021-08-31 | 中国电子技术标准化研究院 | Radio frequency impedance measuring method |
-
2017
- 2017-05-23 CN CN201720579053.2U patent/CN206725656U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109444588A (en) * | 2018-11-15 | 2019-03-08 | 东南大学 | A kind of LCR measuring system based on FPGA+DDS+PLL |
| CN109541315A (en) * | 2018-12-07 | 2019-03-29 | 桂林电子科技大学 | A kind of portable mono port vector impedance analyzer |
| CN113075456A (en) * | 2021-03-18 | 2021-07-06 | 常州同惠电子股份有限公司 | High-precision alternating-current impedance testing system and testing method thereof |
| CN113325237A (en) * | 2021-05-21 | 2021-08-31 | 中国电子技术标准化研究院 | Radio frequency impedance measuring method |
| CN113311240A (en) * | 2021-07-29 | 2021-08-27 | 佛山市联动科技股份有限公司 | Superheterodyne high-frequency impedance test equipment |
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