CN209117851U - A kind of numerical frequency source device based on FPGA - Google Patents
A kind of numerical frequency source device based on FPGA Download PDFInfo
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- CN209117851U CN209117851U CN201821603211.4U CN201821603211U CN209117851U CN 209117851 U CN209117851 U CN 209117851U CN 201821603211 U CN201821603211 U CN 201821603211U CN 209117851 U CN209117851 U CN 209117851U
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- fpga
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- frequency
- control circuit
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Abstract
The numerical frequency source device based on FPGA that the utility model discloses a kind of, it includes input control circuit, FPGA control circuit, frequency synthesizer circuit and the first crystal oscillating circuit, first crystal oscillating circuit is separately connected FPGA control circuit and frequency synthesizer circuit, the input control circuit connects FPGA control circuit, and the FPGA control circuit is also connected with frequency synthesizer circuit.The utility model produces the good digital frequency source that the baseband signal that various complexity can be achieved, signal spurious reduction are strong, can provide the signal for encoding continuous frequency modulation mode with interference free performance by the programmable features of FPGA control circuit and the frequency synthesis characteristic of frequency synthesizer circuit.
Description
Technical field
The utility model relates to radio detection and ranging technical field, in particular to a kind of numerical frequency based on FPGA
Source device.
Background technique
Millimetre-wave radar is the radar that work is detected in millimeter wave band.In millimetre-wave radar work, for its frequency
Source whether can generate various complex baseband signals, generate jamproof coding CW/FM continuous wave/frequency modulated modulated signal and for a long time normally and
Stable work, this is particularly significant and necessary for whether millimetre-wave radar can work normally.
It is realized currently, the frequency source implementation of millimetre-wave radar usually has by Direct Digital Frequency Synthesizers (DDS)
It is realized with by frequency synthesizer of phase locking (PLL).For the frequency source provided by direct synthesizer (DDS), although tool
There is the advantage that frequency stability is high, output phase noise is low and stable and reliable in work, but there is also working frequencies lower, spuious ratio
The deficiencies of more serious, volume is larger and higher cost place.The frequency source provided for passing through frequency synthesizer of phase locking (PLL),
Its frequency stability exported depends on a reference source, and error is larger when work.
Thus the prior art could be improved and improve.
Utility model content
Place in view of above-mentioned deficiencies of the prior art, the purpose of this utility model is to provide a kind of numbers based on FPGA
Frequency source device, with can be achieved, the baseband signal of various complexity, signal spurious reduction is strong, can provide with interference free performance
The advantages of encoding the signal of continuous frequency modulation mode.
In order to achieve the above object, the utility model takes following technical scheme:
A kind of numerical frequency source device based on FPGA, including input control circuit, FPGA control circuit, frequency synthesis electricity
Road and the first crystal oscillating circuit, first crystal oscillating circuit are separately connected FPGA control circuit and frequency synthesizer circuit, the input
Control circuit connects FPGA control circuit, and the FPGA control circuit is also connected with frequency synthesizer circuit.
In the numerical frequency source device based on FPGA, the FPGA control circuit include input control interface, when
Clock unit, main control unit, frequency synthesis control interface and ROM cell, the clock unit are separately connected the first crystal oscillating circuit, defeated
Enter control interface and main control unit, the input control interface is separately connected input control circuit and main control unit, the frequency
Synthesis control interface is separately connected main control unit and frequency synthesizer circuit, and the ROM cell connects main control unit.
In the numerical frequency source device based on FPGA, the frequency synthesizer circuit includes AD9910 chip and filtering
Unit, the AD9910 chip are separately connected frequency synthesis control interface, filter unit and the first crystal oscillating circuit.
In the numerical frequency source device based on FPGA, the FPGA control circuit further includes for frequency source
The feedback signal interface that working condition is fed back, the feedback signal interface connect main control unit.
In the numerical frequency source device based on FPGA, the FPGA control circuit further includes same for generating first
The synchronization signal unit of signal and the second synchronization signal is walked, the synchronization signal unit connects main control unit.
In the numerical frequency source device based on FPGA, the FPGA control circuit further includes unit to be developed, institute
State unit connection main control unit to be developed.
In the numerical frequency source device based on FPGA, the filter unit include connect with AD9910 chip it is ellipse
Round belt bandpass filter.
In the numerical frequency source device based on FPGA, the numerical frequency source device based on FPGA further includes
Two crystal oscillating circuits, the second crystal oscillating circuit rate of connections combiner circuit.
In the numerical frequency source device based on FPGA, the reference clock frequency that first crystal oscillating circuit provides is
50Mhz。
In the numerical frequency source device based on FPGA, the cutoff frequency point of the ellipse bandpass filter is respectively
200MHz and 400MHz.
Compared to the prior art, the numerical frequency source device provided by the utility model based on FPGA, including input control
Circuit, FPGA control circuit, frequency synthesizer circuit and the first crystal oscillating circuit, first crystal oscillating circuit are separately connected FPGA control
Circuit and frequency synthesizer circuit, the input control circuit connect FPGA control circuit, and the FPGA control circuit is also connected with frequency
Rate combiner circuit.The utility model is special by the frequency synthesis of the programmable features and frequency synthesizer circuit of FPGA control circuit
Property, produce that the baseband signal that various complexity can be achieved, signal spurious reduction are strong, can provide the coding with interference free performance connects
The good digital frequency source of the signal of continuous hopping pattern.
Detailed description of the invention
Fig. 1 is the schematic block circuit diagram of the numerical frequency source device provided by the utility model based on FPGA.
Fig. 2 is the big of the coding continuous frequency modulation wave mode of the numerical frequency source device provided by the utility model based on FPGA
The waveform diagram of triangular wave and small triangular wave.
Specific embodiment
The utility model provides a kind of numerical frequency source device based on FPGA, to make the purpose of this utility model, technology
Scheme and effect are clearer, clear, and the utility model is further described as follows in conjunction with drawings and embodiments.It should
Understand, specific embodiment described herein only to explain the utility model, is not used to limit the utility model.
Referring to Fig. 1, the schematic block circuit diagram of the numerical frequency source device provided by the utility model based on FPGA, described
Numerical frequency source device based on FPGA includes input control circuit 10, FPGA control circuit 20, frequency synthesizer circuit 30 and
One crystal oscillating circuit 40, first crystal oscillating circuit 40 is separately connected FPGA control circuit 20 and frequency synthesizer circuit 30, described defeated
Enter control circuit 10 and connect FPGA control circuit 20, the FPGA control circuit 20 is also connected with frequency synthesizer circuit 30.
Wherein, frequency synthesizer circuit 20 is set as having both direct synthesizer (DDS) and frequency synthesizer of phase locking (PLL)
Structure and advantage, by frequency synthesizer circuit can overcome the problems, such as DDS clutter mostly with output frequency it is low, PLL can also be solved
The not high problem of resolution ratio.FPGA control circuit 20 can realize the control system in simple numerical frequency source, convenient for digital frequency
High speed transformation and processing are carried out between each working condition in rate source.
First crystal oscillating circuit 40 connects FPGA control circuit 20 and frequency synthesizer circuit 30 by CA cable assembly, and is the two
Reference clock is provided.For input control circuit 10 towards user is used, the operating mode of FPGA control circuit 20, example is may be selected in user
Such as system reset, single-tone mode, upper frequency sweep mode, coding continuous frequency modulation wave mode and reserved mode.
Input control circuit is mainly made of interlock circuit in the radar chip of millimetre-wave radar, the millimetre-wave radar core
Piece may be selected the chip of AWR1243, STRADA770 and remaining model with similar functions, input control circuit it is specific
Structure and and its working principle of input control signal be the ordinary skill in the art, therefore details are not described herein for the utility model.
Input control signal is sent out to FPGA control circuit 20 by input control circuit 10, can be run and is stored in advance in
Each operating mode program in FPGA control circuit 20 makes FPGA control circuit 20 send out frequency synthesis and controls signal to frequency
Combiner circuit 30, so that frequency synthesizer circuit 30 generates required analog signal and is filtered to it, final generate can
It realizes complicated baseband signal and inhibits spuious high performance frequency source.
Preferably, in order to reduce the shadow for exporting spurious signal in high performance frequency source signal in frequency synthesizer circuit 30
It rings, and also to can reduce the shadow for the high performance frequency source signal that the first crystal oscillating circuit 40 exports frequency synthesizer circuit 30
It rings, the second crystal oscillating circuit 50 connecting with frequency synthesizer circuit 30 can also be set.Second crystal oscillating circuit 50 provides one and the
The signal of the unequal frequency of one crystal oscillating circuit 40 is not involved in the operation of frequency synthesizer circuit 30 to frequency synthesizer circuit 30.
In the particular embodiment, the FPGA control circuit 20 includes input control interface 11, clock unit 12, master control
Unit 13, frequency synthesis control interface 14 and ROM cell 15, the clock unit 12 are separately connected the first crystal oscillating circuit 40, defeated
Enter control interface 11 and main control unit 13, the input control interface 11 is separately connected input control circuit 10 and main control unit
13, the frequency synthesis control interface 14 is separately connected main control unit 13 and frequency synthesizer circuit 30, and the ROM cell 15 connects
Main control unit 13.
Wherein, ROM cell 15 plays the role of storing pre-set programs；Clock unit 12 is for receiving the first crystal oscillating circuit 40
Reference clock, and the clock of synchronous input control signal and main control unit 13；Main control unit 13 connects for receiving input control
The input control signals of 11 input of mouth, issue frequency synthesis by frequency synthesis control interface 14 after treatment and control signal extremely
Frequency synthesizer circuit.The FPGA chip that such as XC6SLX150 model specifically may be selected in the FPGA control circuit is realized.
Further, the FPGA control circuit 20 further includes the feedback fed back for the working condition to frequency source
Signaling interface 16, the feedback signal interface 16 connect main control unit 13.Feedback signal interface 16 connects especially by feed circuit
The frequency source of frequency synthesizer circuit output is connect, and the working condition of frequency source is fed back so that main control unit 13 corrects mistake
Accidentally, guarantee the stability of the high performance frequency source signal of output.
Further, the FPGA control circuit 20 further includes for generating the first synchronization signal and the second synchronization signal
Synchronization signal unit (not shown), the synchronization signal unit connects main control unit.When synchronization signal unit generates the
After one synchronization signal and the second synchronization signal, FPGA is controlled by using the first synchronization signal and the second synchronization signal, it can be with
Realize the size triangular signal of coding continuous frequency modulation wave mode.Certainly, the first synchronization signal and the second synchronization signal can also be by
The corresponding interface and main control unit 13 is sent on external input fpga chip.Finally obtained coding CW/FM continuous wave/frequency modulated modulated signal can be with
It tests the speed angle measurement for millimetre-wave radar, and there is anti-interference function to same money millimetre-wave radar, high frequency resolution can achieve
0.23Hz or more.
Further types of signal, the FPGA are exported according to practical situations for the ease of FPGA control circuit 20 is subsequent
Control circuit 20 further includes unit 17 to be developed, and the unit 17 to be developed connects main control unit 13.Unit 17 to be developed utilizes
The circuit programmable characteristic of FPGA, the logic gate array that user can be freely combined in unit 17 to be developed are different to realize
Circuit function.
In a more specific embodiment, the frequency synthesizer circuit 30 includes AD9910 chip 31 and filter unit 32, institute
It states AD9910 chip 31 and is separately connected frequency synthesis control interface 14, filter unit 32 and the first crystal oscillating circuit 40.
AD9910 chip 31 is the Direct Digital Frequency Synthesizers (DDS) of a built-in 14 bit DAC, is based on AD9910
The temporal characteristics of chip 31 support quick battery saving mode and starting deep sleep mode, energy-efficient.And AD9910 chip
31 also have PLL double frequency function, i.e., AD9910 chip 31 frequency synthesizer circuit may be implemented needed for function.Filter unit 32 can
The high performance frequency source output signal exported to AD9910 chip 31 is filtered, and the interference of extraneous clutter is effectively reduced.
Specifically, filter unit 32 realizes filter function using filter.Frequent Filters by element have active filter,
Passive filter, active filter is at high cost, and technology is immature, and is chiefly used in low current；Passive filter technology maturation, cost
It is low, maintenance can not had to substantially.Passive filter has low-pass filter, bandpass filter, high-pass filter, band resistance by passband point
Filter etc., millimetre-wave radar frequency source frequency passband is 100MHz, therefore the utility model selects bandpass filter.
Bandpass filter has Butterworth mode filter, Chebyshev's mode filter, elliptic filter, Bart by characteristic point
Though amplitude is flat in Butterworth mode filter passband, passband Out-of-band rejection is smaller, and passband squareness factor is poor；Chebyshev
Though mode filter leads to, Out-of-band rejection is stronger, and amplitude fluctuation is larger in passband, and passband squareness factor is not high；Ellipse filtering
Device passband under the conditions of identical order, suppressed frequency band approximation properties are good, and passband squareness factor is good.Therefore, in the utility model
Filter unit 32 specifically includes elliptic filter, and elliptic filter connect with AD9910 chip and filters the output of AD9910 chip
High performance frequency source output signal.
Preferably, the reference clock frequency that first crystal oscillating circuit 40 provides is 50Mhz, and the first crystal oscillating circuit 40 is logical
Cross crystal oscillator realization.Based on the requirement of millimetre-wave radar pass band, select the crystal oscillator of the frequency as a reference source, it can not only be
Frequency multiplication value is obtained in the inner PLL frequency multiplication optimum range of AD9910 chip 31, it is also effective to reduce the spuious influence of crystal oscillator, it reduces
The unstability of PLL frequency multiplication in AD9910 chip 31.Use band logical for 200MHz to 400MHz(i.e. cutoff frequency in filter unit 32
Rate point is respectively 200MHz and 400MHz) elliptic filter, extraneous clutter can be reduced and inhibit it to AD9910 chip 31
Influence.
In order to better understand the present invention, in conjunction with Fig. 1, the work of the numerical frequency source device based on FPGA in the present embodiment
Make process are as follows:
First crystal oscillating circuit provides reference clock to FPGA circuitry and AD9910 chip by CA cable assembly.FPGA circuitry is logical
After crossing the input control signal of input control interface input control circuit sending, procedure selection according to the pre-stored data is corresponding
Operating mode, by frequency synthesis control interface send frequency synthesis control signal to the AD9910 core in frequency synthesizer circuit
Piece, AD9910 chip are handled and are exported required analog signal to frequency synthesis control signal, which passes through ellipse
Generating after circle filter filtering can be achieved complicated baseband signal and inhibits spuious good digital frequency source, i.e., this is practical new
The numerical frequency source device based on FPGA that type provides.
Wherein, the first synchronization signal and the second synchronization signal are realized by control program in FPGA control circuit encodes continuously
Frequency modulation wave mode, the swept-frequency signal of generation can mating setting corresponding encoded as needed, to realize anti-dry between frequency source
It disturbs.As shown in Fig. 2, in a sending cycle of AD9910 chip assignment twice can be carried out to frequency sweep mode, and sweep twice
Frequency does not have time interval, to realize the big triangular wave and small triangular wave in Fig. 2.Pass through ROM cell in FPGA circuitry, Mei Geyi
The section time sends the low-limit frequency or highest frequency of a frequency sweep mode, to effectively improve anti-interference ability.
In addition, the numerical frequency source device provided by the utility model based on FPGA can be applied in millimetre-wave radar system
The fields such as system, remote sensing telemetering or millimetre-wave attenuator, and stable complex baseband signal, anti-interference is provided for the equipment in these fields
The signals such as coding CW/FM continuous wave/frequency modulated modulated signal, effectively maintain the normal work of equipment.
In conclusion a kind of numerical frequency source device based on FPGA provided by the utility model comprising input control
Circuit, FPGA control circuit, frequency synthesizer circuit and the first crystal oscillating circuit, first crystal oscillating circuit are separately connected FPGA control
Circuit and frequency synthesizer circuit, the input control circuit connect FPGA control circuit, and the FPGA control circuit is also connected with frequency
Rate combiner circuit.The utility model is special by the frequency synthesis of the programmable features and frequency synthesizer circuit of FPGA control circuit
Property, produce that the baseband signal that various complexity can be achieved, signal spurious reduction are strong, can provide the coding with interference free performance connects
The good digital frequency source of the signal of continuous hopping pattern.
It is understood that for those of ordinary skills, can with technical solution according to the present utility model and
The design of its utility model is subject to equivalent substitution or change, and all these changes or replacement all should belong to appended by the utility model
Scope of protection of the claims.
Claims (10)
1. a kind of numerical frequency source device based on FPGA, including input control circuit, which is characterized in that further include FPGA control
Circuit, frequency synthesizer circuit and the first crystal oscillating circuit, first crystal oscillating circuit is separately connected FPGA control circuit and frequency is closed
At circuit, the input control circuit connects FPGA control circuit, and the FPGA control circuit is also connected with frequency synthesizer circuit.
2. the numerical frequency source device according to claim 1 based on FPGA, which is characterized in that the FPGA control circuit
Including input control interface, clock unit, main control unit, frequency synthesis control interface and ROM cell, the clock unit difference
The first crystal oscillating circuit, input control interface and main control unit are connected, the input control interface is separately connected input control circuit
And main control unit, the frequency synthesis control interface are separately connected main control unit and frequency synthesizer circuit, the ROM cell connection
Main control unit.
3. the numerical frequency source device according to claim 2 based on FPGA, which is characterized in that the frequency synthesizer circuit
Including AD9910 chip and filter unit, the AD9910 chip is separately connected frequency synthesis control interface, filter unit and
One crystal oscillating circuit.
4. the numerical frequency source device according to claim 2 based on FPGA, which is characterized in that the FPGA control circuit
It further include the feedback signal interface fed back for the working condition to frequency source, the feedback signal interface connects master control list
Member.
5. the numerical frequency source device according to claim 2 based on FPGA, which is characterized in that the FPGA control circuit
It further include the synchronization signal unit for generating the first synchronization signal and the second synchronization signal, the synchronization signal unit connection master
Control unit.
6. the numerical frequency source device according to claim 2 based on FPGA, which is characterized in that the FPGA control circuit
It further include unit to be developed, the unit to be developed connects main control unit.
7. the numerical frequency source device according to claim 3 based on FPGA, which is characterized in that the filter unit includes
The oval bandpass filter being connect with AD9910 chip.
8. the numerical frequency source device according to claim 1 based on FPGA, which is characterized in that the number based on FPGA
Word frequency source device further includes the second crystal oscillating circuit, the second crystal oscillating circuit rate of connections combiner circuit.
9. the numerical frequency source device according to claim 1 based on FPGA, which is characterized in that first crystal oscillating circuit
The reference clock frequency of offer is 50Mhz.
10. the numerical frequency source device according to claim 7 based on FPGA, which is characterized in that the ellipse band logical filter
The cutoff frequency point of wave device is respectively 200MHz and 400MHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821603211.4U CN209117851U (en) | 2018-09-29 | 2018-09-29 | A kind of numerical frequency source device based on FPGA |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821603211.4U CN209117851U (en) | 2018-09-29 | 2018-09-29 | A kind of numerical frequency source device based on FPGA |
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| Publication Number | Publication Date |
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| CN209117851U true CN209117851U (en) | 2019-07-16 |
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| CN201821603211.4U Expired - Fee Related CN209117851U (en) | 2018-09-29 | 2018-09-29 | A kind of numerical frequency source device based on FPGA |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114499501A (en) * | 2022-04-19 | 2022-05-13 | 成都市克莱微波科技有限公司 | Frequency source dynamic control method, control device and system |
-
2018
- 2018-09-29 CN CN201821603211.4U patent/CN209117851U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114499501A (en) * | 2022-04-19 | 2022-05-13 | 成都市克莱微波科技有限公司 | Frequency source dynamic control method, control device and system |
| CN114499501B (en) * | 2022-04-19 | 2022-08-26 | 成都市克莱微波科技有限公司 | Frequency source dynamic control method, control device and system |
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| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
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Granted publication date: 20190716 Termination date: 20200929 |