CN207586312U - A kind of digital frequency meter based on FPGA - Google Patents
A kind of digital frequency meter based on FPGA Download PDFInfo
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- CN207586312U CN207586312U CN201820378546.4U CN201820378546U CN207586312U CN 207586312 U CN207586312 U CN 207586312U CN 201820378546 U CN201820378546 U CN 201820378546U CN 207586312 U CN207586312 U CN 207586312U
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Abstract
A kind of digital frequency meter based on FPGA of the utility model is formed including AGC broadband channels amplifying circuit, signal transformation circuit, frequency measurement circuit, data processing and display circuit, power circuit.Wherein frequency measurement circuit includes equally accurate frequency measurement circuit, time interval measuring circuit, pulse duty factor measuring circuit.Measured signal is inputted from AGC broadband channels amplifying circuit, AGC broadband channels amplification circuit output end connection signal shaping circuit input terminal, signal transformation circuit output terminal connects frequency measurement circuit input terminal, frequency measurement circuit output terminal connects data processing and display circuit input terminal, power circuit are connected with AGC broadband channels amplifying circuit, signal transformation circuit.The utility model uses above technical scheme, can be used for measuring sine wave freuqency, square-wave pulse signal duty ratio, square-wave signal time interval.
Description
Technical field
The utility model is related to a kind of digital frequency meter, more specifically, being related to a kind of digital frequency meter based on FPGA.
Background technology
Frequency is the important parameter of electric signal, and measuring signal frequency has important meaning in engineering.Frequency measurement method
Generally there are analog- and digital- two methods, the method that tradition relies on analog device, measuring system is complicated, needs dedicated devices, hardware
Of high cost and precision is not high.With the development of science and technology high-frequency signal, using more and more common, simple digital frequency meter is
The needs of measurement frequency cannot be met, the higher frequency of measurement, more accurate precision, wider array of measurement range is pursued and have become number
The demand for development of word frequency meter.With the development of integrated circuit, various high speeds are completed using large scale integrated circuit, high-precision
The design of electronic instrument has become a kind of trend.FPGA has high speed processing ability, and core frequency is up to up to a hundred million, simultaneously
It also possesses abundant I/O resource and a large amount of soft core, can facilitate carry out secondary development.The most significant features of FPGA are internal
Program parallelization is run, and handles the with better function of data.Therefore, the design that digital high frequency frequency meter is realized using FPGA is studied,
And be applied in the frequency measurement of high-frequency signal, it is of great significance.
Utility model content
The utility model is mainly solving the technical problems that provide a kind of digital frequency meter based on FPGA, using equally accurate
Measuring Frequency Method can measure 0.1Hz~113MHz, the sine wave of voltage effective value range 10mV~1V, measurement error 10-7；It can
To measure 1Hz~5MHz, voltage peak-to-peak value 50mV~1V, the square-wave pulse letter of the range 5%~95% of pulse signal duty ratio
Number duty ratio, relative error 10-2；100Hz~1MHz, voltage peak-to-peak value 50mV~1V, the range of time interval can be measured
The square-wave signal time interval of 0.1us~10ms.
In order to solve the above technical problems, the technical solution used by the utility model is：
A kind of digital frequency meter based on FPGA, including AGC broadband channels amplifying circuit, signal transformation circuit, frequency measurement electricity
Road, data processing and display circuit, power circuit, wherein frequency measurement circuit include equally accurate frequency measurement circuit, time interval measurement
Circuit, pulse duty factor measuring circuit, measured signal are inputted from AGC broadband channels amplifying circuit, AGC broadband channels amplifying circuit
Output terminal connection signal shaping circuit input terminal, signal transformation circuit output terminal connection frequency measurement circuit input terminal, frequency measurement circuit are defeated
Outlet connects data processing and display circuit input terminal, power circuit and AGC broadband channels amplifying circuit, signal transformation circuit phase
Even.
Preferably, AGC broadband channels amplifying circuit uses VCA820 as linear amplifier chip.
Preferably, AGC broadband channels amplifying circuit uses OPA820 as voltage feedback type amplifier chip.
Preferably, AGC broadband channels amplifying circuit uses OPA690 as in-phase proportion operational amplifier chip.
Preferably, the signal transformation circuit uses hysteresis comparator TLV3502.
Preferably, the frequency measurement circuit is realized using ALTEAR Cyclone I EP1C6Q240C8N FPGA.
Preferably, the data processing circuit uses 80C51IP cores.
Preferably, the display circuit uses LCD12864 display screens.
Preferably, the power circuit uses linear stabilized power supply.
The utility model compared with prior art, has following technique effect using above technical scheme：Measurement range is big,
High certainty of measurement has multiple functions, can be widely used in into the measurement of line frequency, time interval, pulse duty factor
High occasion is required measurement accuracy.
Description of the drawings
Fig. 1 is the functional block diagram of the utility model；
Fig. 2 is the schematic diagram of AGC broadband channels amplifier in the utility model；
Fig. 3 is the schematic diagram of shaping circuit in the utility model；
Fig. 4 is the functional block diagram of the utility model medium accuracy frequency measurement；
Fig. 5 is the functional block diagram that the utility model pulse duty factor measures；
Fig. 6 is the functional block diagram of the utility model time interval measurement.
Specific embodiment
The utility model is described further below in conjunction with the accompanying drawings.
A kind of digital frequency meter based on FPGA of the utility model, including AGC broadband channels amplifying circuit, signal shaping electricity
Road, frequency measurement circuit, data processing and display circuit, power circuit, wherein frequency measurement circuit include equally accurate frequency measurement circuit, time
Interval measuring circuit, pulse duty factor measuring circuit, measured signal are inputted from AGC broadband channels amplifying circuit, AGC broadband channels
Amplification circuit output end connection signal shaping circuit input terminal, signal transformation circuit output terminal connection frequency measurement circuit input terminal, is surveyed
Frequency circuit output terminal connects data processing and display circuit input terminal, power circuit and AGC broadband channels amplifying circuit, signal are whole
Shape circuit is connected.
AGC broadband channels amplifying circuit is using VCA820 as linear amplifier chip.
AGC broadband channels amplifying circuit is using OPA820 as voltage feedback type amplifier chip.
AGC broadband channels amplifying circuit is using OPA690 as in-phase proportion operational amplifier chip.
The signal transformation circuit uses hysteresis comparator TLV3502.
The frequency measurement circuit is realized using ALTEAR Cyclone I EP1C6Q240C8N FPGA.
The data processing circuit uses 80C51IP cores.
The display circuit uses LCD12864 display screens.
The power circuit uses linear stabilized power supply.
As shown in Figure 1, a kind of digital frequency meter based on FPGA of present embodiment include AGC broadband channels amplifying circuit,
Signal transformation circuit, frequency measurement circuit, data processing and display circuit, power circuit.Wherein frequency measurement circuit includes equally accurate frequency measurement
Circuit, time interval measuring circuit, pulse duty factor measuring circuit.Wherein, measured signal is defeated from AGC broadband channels amplifying circuit
Enter.
As shown in Fig. 2, the AGC broadband channels amplifying circuit signal is amplified from VCA820 in-phase ends, by
The voltage of OPA820 outputs enters from the VG feet of VCA820 controls VCA820 output signals, and the signal of VCA820 outputs is again
10 times of amplifications are carried out by OPA690, the signal of OPA690 outputs passes through OPA820 and threshold value using detector diode detection
Voltage is compared, then removes to be input to the VG feet of VCA820, can thus accomplish automatic growth control.
The shaping circuit as shown in Figure 3 carries out shaping to the output signal of AGC broadband channels amplifying circuit, by sine wave
Whole is square wave, then outputs a signal to FPGA chip circuit, FPGA chip circuit includes frequency measurement, pulse duty factor is surveyed
Amount, time interval measurement, illustrate separately below.
As shown in figure 4, the Equal-precision digital frequency measure circuit uses equal precision measuring frequency way.In measurement process, there are two
Counter respectively counts standard signal fc and measured signal fx simultaneously.Standard signal provides gate opening letter first for 100MHz
Number (preset gate rising edge), this hour counter does not start counting up, but until the rising edge of measured signal arrives, it counts
Device just really starts counting up.Then then, counter does not stop counting preset closing gate signal (failing edge) immediately, but
Just terminate to count until the rising edge of measured signal arrives, complete one-shot measurement process.
As shown in figure 5, the pulse duty factor measuring circuit is similar with Equal-precision digital frequency measure circuit.Microcontroller receives
The count value NC of counter 1, the count value Nx1 of counter 2, counter 3 count value Nx2, microcontroller carry out data calculating
The size of Nx1 and Nx2 are first determined whether before, if Nx2 is much larger than Nx1 (such as Fig. 3-6), are calculated for Nx2, at this time duty ratio
It is worth and is：；If Nx1 is much larger than Nx2, calculated with Nx1, the value of duty ratio is at this time：。
As shown in fig. 6, the time interval measuring circuit and pulse duty factor measuring circuit principle are basically identical.Microcontroller
Receive the count value N2 of the count value NC of counter 1, the count value N1 of counter 2, counter 3.If N1 is much larger than N2, use
Carry out N1 calculating, time difference is at this time：.If N2 is much larger than N1, calculated for N2, at this time the value of time difference
For：。
The data processing and display circuit are verified existing by 80C51IP.Processing passes through the data after fpga chip measurement, warp
After calculating, result is sent to LCD12864 and is shown.
The power circuit uses linear stabilized power supply.Linear stabilized power supply uses full-bridge rectifier filter, by transformer, protects
Danger pipe, rectifier bridge, input filter, three terminal regulator and output filter circuit composition, export 5V voltages, for giving AGC broadbands
Channel amplifying circuit, signal transformation circuit power supply.
AGC broadband channels amplifying circuit is wide by the amplifier VCA820 controlled with dB linear variable gains and outside
Band amplifier OPA690 and OPA820 is collectively constituted.VCA820 chips are a with 150MHz small signal bandwidths and 1700V/us
The dc-couple of slew rate, wide bandwidth linear amplifier, it provides the Differential Input of the single-ended conversion of high impedance, gain control one
As by setting gain resistor and feedback resistance, gain-adjusted range is more than 40dB；OPA690 has high bandwidth, high conversion speed
The advantages that rate, unity gain stable；OPA820 is a 240MHz (G=+2) high bandwidth, and ± 110mA High Output Currents are low defeated
Enter noise, the voltage feedback type amplifier of unity gain stable.
The signal transformation circuit selection comparator is realized.Common comparator has voltage comparator, double threshold ratio
Compared with device (window comparator), hysteresis comparator (Schmidt trigger or hysteresis loop comparator), voltage comparator is suitble to voltage range
The larger circuit system of saltus step.Window comparator is called double-limit comparator, is the rising edge in input signal using two comparators
The comparator different with failing edge turnover voltage, two value between value be window width.Hysteresis comparator also there are two thresholding,
For jam-to-signal in input signal it is more serious when, it is unnecessary that the output of comparator can be influenced to have by these interference signals
Threshold transition, in a comparator add in amount of positive feedback can be very good by these interference removal, inhibit output frequent saltus step
And concussion.Relative to window comparator, hysteresis comparator has better antijamming capability, and peripheral circuit is simpler, uses
Chip it is less.
The frequency measurement circuit is encapsulated in FPGA.FPGA has been internally integrated phaselocked loop, can be by external clock frequency multiplication, core
Frequency can reach hundreds of million.Using powerful VHDL language, complexity can be described with succinct specific source code
Logic control, the parallel processing structure of FPGA can realize real-time frequency measurement effect.Equally accurate frequency measurement electricity is write with VHDL language
Then road, time interval measuring circuit, pulse duty factor measuring circuit VHDL program are written in FPGA.It is integrated using FPGA
80C51IP kernels calculated and shown.System is enormously simplified using the mode of FPGA combination with the MCU, improves number
According to processing capacity.
The data processing and display circuit are realized that 80C51IP kernels are integrated on FPGA by 8051IP kernels.
Linear stabilized power supply is by transformer, protective tube, rectifier bridge, input filter, three terminal regulator and output filtered electrical
Road forms.
More than, the only preferable specific embodiment of the utility model, but the scope of protection of the utility model is not limited to
In this, in the technical scope that any one skilled in the art discloses in the utility model, according to the utility model
Technical solution and its utility model design be subject to equivalent substitution or change, should all cover the scope of protection of the utility model it
It is interior.
Claims (9)
1. a kind of digital frequency meter based on FPGA, it is characterised in that：Including AGC broadband channels amplifying circuit, signal shaping electricity
Road, frequency measurement circuit, data processing and display circuit, power circuit, wherein frequency measurement circuit include equally accurate frequency measurement circuit, time
Interval measuring circuit, pulse duty factor measuring circuit, measured signal are inputted from AGC broadband channels amplifying circuit, AGC broadband channels
Amplification circuit output end connection signal shaping circuit input terminal, signal transformation circuit output terminal connection frequency measurement circuit input terminal, is surveyed
Frequency circuit output terminal connects data processing and display circuit input terminal, power circuit and AGC broadband channels amplifying circuit, signal are whole
Shape circuit is connected.
2. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The AGC broadband channels
Amplifying circuit is using VCA820 as linear amplifier chip.
3. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The AGC broadband channels
Amplifying circuit is using OPA820 as voltage feedback type amplifier chip.
4. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The AGC broadband channels
Amplifying circuit is using OPA690 as in-phase proportion operational amplifier chip.
5. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The signal transformation circuit
Using hysteresis comparator TLV3502.
6. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The frequency measurement circuit uses
ALTEAR Cyclone I EP1C6Q240C8N FPGA are realized.
7. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The data processing circuit
Using 80C51IP cores.
8. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The display circuit uses
LCD12864 display screens.
9. a kind of digital frequency meter based on FPGA according to claim 1, it is characterised in that：The power circuit uses
Linear stabilized power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820378546.4U CN207586312U (en) | 2018-03-20 | 2018-03-20 | A kind of digital frequency meter based on FPGA |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820378546.4U CN207586312U (en) | 2018-03-20 | 2018-03-20 | A kind of digital frequency meter based on FPGA |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207586312U true CN207586312U (en) | 2018-07-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820378546.4U Expired - Fee Related CN207586312U (en) | 2018-03-20 | 2018-03-20 | A kind of digital frequency meter based on FPGA |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109116107A (en) * | 2018-08-21 | 2019-01-01 | 山东中创软件商用中间件股份有限公司 | A kind of digital frequency meter |
| CN111665708A (en) * | 2020-06-10 | 2020-09-15 | 中国测试技术研究院电子研究所 | Sweep frequency time detection method based on FPGA circuit |
| CN112782487A (en) * | 2019-11-08 | 2021-05-11 | 航天科工惯性技术有限公司 | Duty ratio detection system |
| CN114371342A (en) * | 2022-03-21 | 2022-04-19 | 国仪量子(合肥)技术有限公司 | FPGA (field programmable Gate array), real-time signal frequency measurement method based on FPGA and lock-in amplifier |
-
2018
- 2018-03-20 CN CN201820378546.4U patent/CN207586312U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109116107A (en) * | 2018-08-21 | 2019-01-01 | 山东中创软件商用中间件股份有限公司 | A kind of digital frequency meter |
| CN112782487A (en) * | 2019-11-08 | 2021-05-11 | 航天科工惯性技术有限公司 | Duty ratio detection system |
| CN111665708A (en) * | 2020-06-10 | 2020-09-15 | 中国测试技术研究院电子研究所 | Sweep frequency time detection method based on FPGA circuit |
| CN111665708B (en) * | 2020-06-10 | 2022-05-03 | 中国测试技术研究院电子研究所 | Sweep frequency time detection method based on FPGA circuit |
| CN114371342A (en) * | 2022-03-21 | 2022-04-19 | 国仪量子(合肥)技术有限公司 | FPGA (field programmable Gate array), real-time signal frequency measurement method based on FPGA and lock-in amplifier |
| CN114371342B (en) * | 2022-03-21 | 2022-05-27 | 国仪量子(合肥)技术有限公司 | FPGA (field programmable Gate array), real-time signal frequency measurement method based on FPGA and lock-in amplifier |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180706 Termination date: 20190320 |
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| CF01 | Termination of patent right due to non-payment of annual fee |