CN108063620A - A kind of analog-to-digital conversion circuit system of radio telescope - Google Patents
A kind of analog-to-digital conversion circuit system of radio telescope Download PDFInfo
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- CN108063620A CN108063620A CN201711433695.2A CN201711433695A CN108063620A CN 108063620 A CN108063620 A CN 108063620A CN 201711433695 A CN201711433695 A CN 201711433695A CN 108063620 A CN108063620 A CN 108063620A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/10—Calibration or testing
- H03M1/1071—Measuring or testing
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
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Abstract
The present invention provides a kind of analog-to-digital conversion circuit system of radio telescope, including collection of simulant signal unit and AD conversion unit；Collection of simulant signal unit, the radiofrequency signal for antenna to be collected are amplified and are mixed, and the intermediate-freuqncy signal of the power requirement of AD conversion unit is met with generation；Also, the IF passband signal of corresponding frequency band in intermediate-freuqncy signal is extracted according to instruction；It is additionally operable to provide clock for AD conversion unit and rear end FPGA circuitry system；AD conversion unit uses the alternating expression modulus conversion chip that polylith bandwidth is 12bit for 3.2Gsps, precision, for IF passband signal to be converted to digital signal.Radio astronomy data high-speed, high quality, reliable and stable acquisition demand can be met, the signal of different-waveband can be received, meet the demand of different tasks of science, suitable for the data application of ultra wide band, flexibility is high, and good reliability is low in energy consumption, it is at low cost, take into account high sampling bandwidth and high sampling precision.
Description
Technical field
The present invention relates to astronomical technical field, more particularly, to a kind of analog-to-digital conversion circuit system of radio telescope.
Background technology
Receiver system is the important component of telescope, is the key factor for determining telescope performance.It is building
In 500 meters of spherical radio telescope FAST be single port footpath radio telescope maximum in the world, have very high resolution ratio, this
It is itself big advantage.The working frequency range of FAST can be simultaneously fitted to play FAST advantages itself as far as possible in 70MHz-3GHz
Different astronomical observation targets is answered, it is necessary to which the reception function of FAST flexibly covers entire frequency band.
At present, the receiver in radio telescope can only selectively observe specific bandwidth.For some scientific goals, than
Such as spectral line, if the bandwidth of 2-3GHz need to be checked, 200MHz can only be checked every time, i.e. check bandwidth, the 2.2- of 2-2.2GHz successively
The bandwidth of 2.4GHz, the bandwidth of 2.4-2.6GHz, the bandwidth of the bandwidth of 2.6-2.8GHz and 2.8-3GHz, are imitated so as to cause observation
Rate is relatively low.Such as some scientific goals wish to may search for pulsar, the frequency model of pulse signal (such as delta signal)
It encloses usually wider (especially if preferable time domain delta signals, because time-domain finite, frequency domain is unlimited, so frequency is into
SINC shapes, and be bandwidth without limit for width, only intensity can be progressively low), this when, the specific frequency model of neither one
Search is enclosed, generally requires constantly to attempt, then more gathered datas cover algorithm repeatedly, so that observed efficiency is relatively low.And
And the existing receiver in radio telescope, when obtaining the number of winning the confidence, sampling bandwidth and sampling precision cannot take into account, i.e. sample
In the case of broader bandwidth, sampling precision is low；In the case of sampling precision height, narrow bandwidth is sampled.
The content of the invention
The present invention provides a kind of mould for the radio telescope for overcoming the above problem or solving the above problems at least partly
Number conversion circuitry.
According to an aspect of the present invention, a kind of analog-to-digital conversion circuit system of radio telescope is provided, is believed including simulation
Number collecting unit and AD conversion unit；
Analog-digital conversion circuit as described system is located at the antenna of the radio telescope and the rear end of the radio telescope
Between FPGA circuitry system；
The collection of simulant signal unit, the radiofrequency signal for the antenna to be collected are amplified and are mixed, with
Generation meets the intermediate-freuqncy signal of the power requirement of the AD conversion unit；Also, it is extracted according to instruction in the intermediate-freuqncy signal
The IF passband signal of corresponding frequency band；When being additionally operable to provide for the AD conversion unit and the rear end FPGA circuitry system
Clock；
The AD conversion unit uses the alternating expression analog-to-digital conversion core that polylith bandwidth is 12bit for 3.2Gsps, precision
Piece, for the IF passband signal to be converted to digital signal.
Preferably, the collection of simulant signal unit includes：
Frequency mixing module, the radiofrequency signal for the antenna to be collected are amplified and are mixed, and generation meets the mould
The intermediate-freuqncy signal of the power requirement of number converting unit；
Frequency-selecting module, for according to described instruction, extracting the IF passband signal of the corresponding band in the intermediate-freuqncy signal；
Clock module, for providing local oscillator for the frequency mixing module and being the AD conversion unit and the rear end
FPGA circuitry system provides clock；
Signal assist in synchronization module, for generating the aerial signal of 1pps, so that analog-digital conversion circuit as described system, institute
The frequency stabilizer for stating rear end FPGA circuitry system and signal assist in synchronization module binding realizes locking synchronization.
Preferably, the frequency mixing module includes：The first low-noise amplifier for being sequentially connected electrically, the first fixed attenuator,
First wideband radio frequency amplifier, the first digital variable electronic attenuator, the second fixed attenuator, the second wideband radio frequency amplifier,
3rd fixed attenuator, the 3rd wideband radio frequency amplifier, the second digital variable electronic attenuator and frequency mixer.
Preferably, the frequency-selecting module includes：The digital switch that is electrically connected with the frequency mixer and with the digital switch
Multiple low-pass filters of electrical connection；Wherein, each of the digital switch can set that there are one low-pass filtering in routing path
The intermediate-freuqncy signal is divided into multiple frequency ranges by device, the multiple low-pass filter；The digital switch is according to described instruction by institute
Have can in routing path corresponding one can routing path connect.
Preferably, the multiple low-pass filter is four, and the passband of four low-pass filters is respectively：0-200MHz,
0-400MHz, 0-800MHz and 0-1500MHz.
Preferably, the clock module, including：First voltage controlled oscillator and the second voltage controlled oscillator；Described first is voltage-controlled
Oscillator provides local oscillator for the frequency mixer, and second voltage controlled oscillator is the AD conversion unit and rear end FPGA circuitry
System provides clock.
Preferably, the AD conversion unit further includes signal synchronization receiving module, and the signal synchronization receiving module is used
In the aerial signal for receiving the 1pps.
Preferably, the alternating expression modulus conversion chip is TI ADC12D1600 chips or AF201 chips.
Preferably, the TI ADC12D1600 chips include ADC that two pieces of precision are 12bit preferably, each piece of precision
It is exported for the ADC chips of 12bit with 8 tunnels, the TI ADC12D1600 chips are exported with 16 tunnels.
A kind of analog-to-digital conversion circuit system of radio telescope provided by the invention, can meet radio astronomy data high-speed,
High quality, reliable and stable acquisition demand can receive the signal of different-waveband, meet the demand of different tasks of science, be applicable in
In the data application of ultra wide band, flexibility is high, good reliability, low in energy consumption, at low cost.By the way that the antenna of radio telescope is received
Weak radio-frequency signal amplification, mixing and the filtering arrived, so that the analog-to-digital conversion circuit system is covering the radio telescope
In the case of complete bandwidth, moreover it is possible to the IF passband signal of different frequency range be handled, flexibility is high.Also, the modulus turns
Another effect for changing circuit system is to provide clock for rear end FPGA circuitry system, so as to ensure that the analog-to-digital conversion circuit system
With the synchronism of rear end FPGA circuitry system, accuracy height.Also, it for 3.2Gsps, precision is 12bit's to use polylith bandwidth
Multigroup IF passband signal is converted to multigroup digital signal, the FAST of covering highest 3.2GHz by alternating expression modulus conversion chip
Complete bandwidth.All A/D conversion systems of present CASPER are compared, under similary sampling, precision highest；Under same accuracy, adopt
Sample is most fast, has taken into account high sampling bandwidth and high sampling precision.
Description of the drawings
Fig. 1 is according to a kind of structure chart of the analog-to-digital conversion circuit system of radio telescope provided in an embodiment of the present invention；
Fig. 2 is according to a kind of circuit structure of the frequency mixing module of collection of simulant signal unit provided in an embodiment of the present invention
Figure；
Fig. 3 is according to 4 circuit-switched data waveform of ADC chip testings time-domain signal provided in an embodiment of the present invention and enlarged drawing；
Fig. 4 is the data waveform and amplification after being merged according to ADC chip testings time-domain signal provided in an embodiment of the present invention
Figure；
Fig. 5 is according to the actual measurement noise provided in an embodiment of the present invention based on 156.25MHz signals when theoretical reference value
Schematic diagram；
Fig. 6 is with the change schematic diagram of frequency according to signal strength provided in an embodiment of the present invention；
Fig. 7 is according to ADC chips maximum linear input intensity test schematic diagram provided in an embodiment of the present invention.
Specific embodiment
With reference to the accompanying drawings and examples, the specific embodiment of the present invention is described in further detail.Implement below
Example is not limited to the scope of the present invention for illustrating the present invention.
Receiver is the important component of telescope, is the key factor for determining telescope performance.It looks in the distance for radio
Mirror, astronomical observation have very strong uncertainty, therefore, the reception in radio telescope for the frequency and scope of target observation
Machine needs have very strong flexibility.The analog-to-digital conversion circuit system of a kind of radio telescope provided by the invention, as reception
The essential component of machine system plays the role of vital for the function realization of receiver system.
Fig. 1 be according to a kind of structure chart of the analog-to-digital conversion circuit system of radio telescope provided in an embodiment of the present invention,
As shown in Figure 1, the analog-to-digital conversion circuit system includes collection of simulant signal unit and AD conversion unit；
Analog-digital conversion circuit as described system is located at the antenna of the radio telescope and the rear end of the radio telescope
Between FPGA circuitry system；
The collection of simulant signal unit, the radiofrequency signal for the antenna to be collected are amplified and are mixed, with
Generation meets the intermediate-freuqncy signal of the power requirement of the AD conversion unit；Also, it is extracted according to instruction in the intermediate-freuqncy signal
The IF passband signal of corresponding frequency band；When being additionally operable to provide for the AD conversion unit and the rear end FPGA circuitry system
Clock；
The AD conversion unit uses the alternating expression analog-to-digital conversion core that polylith bandwidth is 12bit for 3.2Gsps, precision
Piece, for the IF passband signal to be converted to digital signal.
Specifically, the radiofrequency signal that the antenna of radio telescope receives is usually fainter, sets the analog-to-digital conversion electric
The effect of road system is to be pre-processed by faint radiofrequency signal and will pass through pretreated radiofrequency signal to carry out modulus
Conversion, for the processing of subsequent processing system, subsequent processing system can be computer, or rear end FPGA circuitry system
System.
It should be noted that above-mentioned preprocessing process includes faint radiofrequency signal is amplified and is mixed, generation is full
The intermediate-freuqncy signal of the power requirement of sufficient analog-to-digital conversion circuit system.And it is extracted according to instruction in the intermediate-freuqncy signal in corresponding frequency band
Frequency passband signal, and analog-to-digital conversion is carried out to the IF passband signal, it is needed applied to different observation.It should be noted that
The instruction can be generated by program language, can also be generated by rear end FPGA circuitry system.
In the present embodiment, AD conversion unit uses the alternating expression mould that polylith bandwidth is 12bit for 3.2Gsps, precision
Number conversion chip, digital signal is converted to by IF passband signal.
Specifically, IF passband signal is carried out sampling processing, quantification treatment and coded treatment, conversion by AD conversion unit
For digital signal.It can realize 12 quantified precisions, the high-speed sampling of the interleave samples pattern of 3.2Gsps.
Another effect of the analog-to-digital conversion circuit system is to provide clock for rear end FPGA circuitry system, so that the modulus
Conversion circuitry is synchronous with the realization of rear end FPGA circuitry system.
The analog-to-digital conversion circuit system of a kind of radio telescope provided in this embodiment, by by the antenna of radio telescope
Weak radio-frequency signal amplification, mixing and the filtering received, so that the analog-to-digital conversion circuit system is in covering, the radio is looked in the distance
In the case of the complete bandwidth of mirror, moreover it is possible to the IF passband signal of different frequency range be handled, flexibility is high.Also, the mould
Another effect of number conversion circuitry is to provide clock for rear end FPGA circuitry system, so as to ensure that the analog to digital conversion circuit
The synchronism of system and rear end FPGA circuitry system, accuracy are high.Also, the polylith bandwidth is used to be for 3.2Gsps, precision
Multigroup IF passband signal is converted to multigroup digital signal, covering highest 3.2GHz by the alternating expression modulus conversion chip of 12bit
FAST complete bandwidths.All A/D conversion systems of present CASPER are compared, under similary sampling, precision highest；Similary essence
Under degree, sampling is most fast, has taken into account high sampling bandwidth and high sampling precision.
Based on above-described embodiment, the present embodiment is made the collection of simulant signal unit in above-described embodiment and is illustrated,
Collection of simulant signal unit includes：
Frequency mixing module, the radiofrequency signal for the antenna to be collected are amplified and are mixed, and generation meets the mould
The intermediate-freuqncy signal of the power requirement of number converting unit；
Frequency-selecting module, for according to described instruction, extracting the IF passband signal of the corresponding band in the intermediate-freuqncy signal；
Clock module, for providing local oscillator for the frequency mixing module and being the AD conversion unit and the rear end
FPGA circuitry system provides clock；
Signal assist in synchronization module, for generating the aerial signal of 1pps, so that analog-digital conversion circuit as described system, institute
The frequency stabilizer for stating rear end FPGA circuitry system and signal assist in synchronization module binding realizes locking synchronization.
A kind of analog-to-digital conversion circuit system of radio telescope provided in this embodiment, by signal synchronization supplementary module,
The aerial signal of 1pps is provided, so that front-end circuitry, analog-to-digital conversion circuit system, rear end FPGA circuitry system and signal
The frequency stabilizer of synchronous supplementary module binding realizes locking synchronization, avoids frequency drift.
Based on above-described embodiment, the present embodiment combination attached drawing, to the mixed of the collection of simulant signal unit in above-described embodiment
Frequency module, which is made, to be illustrated, and Fig. 2 is according to a kind of frequency mixing module of collection of simulant signal unit provided in an embodiment of the present invention
Circuit structure diagram, as shown in Fig. 2, the frequency mixing module includes：The first low-noise amplifier for being sequentially connected electrically, first are fixed
Attenuator, the first wideband radio frequency amplifier, the first digital variable electronic attenuator, the second fixed attenuator, the second wide band radio-frequency
Amplifier, the 3rd fixed attenuator, the 3rd wideband radio frequency amplifier, the second digital variable electronic attenuator and frequency mixer.
Specifically, single treatment module pre-processes the faint radiofrequency signal that antenna receives, and is once located by this
The cooperation of mould amplifiers at different levels in the block and attenuator is managed, makes the power of intermediate-freuqncy signal of final output in analog to digital conversion circuit system
In the working range of system.
First low-noise amplifier is CMA-5043+；First fixed attenuator, the second fixed attenuator and the 3rd, which fix, to decline
It is GAT-5 to subtract device；First wideband radio frequency amplifier, the second wideband radio frequency amplifier and the 3rd wideband radio frequency amplifier are
ADL5610；First digital variable electronic attenuator and the second digital variable electronic attenuator are HMC624LP4, and frequency mixer is
M1-0008。
Such as the type selecting for the first low-noise amplifier, antenna working band scope and existing low noise are put
The each side devices such as gain, noise coefficient, third order intermodulation point and the P1dB output powers of working frequency range, amplifier of big device
Can, consider to select the broad band amplifier CMA-5043+ of Mini-circuits productions.Since the first stage amplifier of receiver controls
Total noise temperature of entire front-end intermediate frequency reception system, so low noise is selected, the amplifier of high-gain.
Its gain ranging is 10.2dB-25.2dB in the frequency range of 0.05GHz-3GHz, high-gain comparatively.Noise
Figure scopes are 0.73-1.1dB, and compared to same frequency range, other devices want small 1dB or so.Higher Output IP3, scope are
31-33.6dBm P1dB output power ranges are 18.9-21.2dBm.
On the other hand, in order to consider that every level-one amplifier gain cannot be too big so that defeated more than the P1dB of next stage amplifier
Going out power makes its saturation and cisco unity malfunction, it is also contemplated that final to-noise ratio can be more as big as possible, while to ensure to export
To analog-to-digital conversion circuit system signal power value no more than its maximum operating range 6dBm, so before considering receiver
Type selecting and ingenious combination of the wideband radio frequency amplifiers at different levels with digital variable electronic attenuator in terminal circuit system.First low noise
Add the fixed attenuator of a 5dB after amplifier, for inhibiting the standing wave between higher level and this grade of wideband radio frequency amplifier, and select
Working frequency range is 0.03-6GHz, and the wideband radio frequency amplifier ADL5610 that gain ranging is 17.5dB amplifies signal three-level.It is whole
There are two digital variable resistance attenuator HMC624LP4 in a front-end circuitry, their adjustable range is 0-31.5dB, step
Into being 0.5dB.
A kind of analog-to-digital conversion circuit system of radio telescope provided in this embodiment faint is penetrated by what is received to antenna
Frequency signal is amplified and is mixed, and generation meets the power requirement of subsequent AD conversion unit, is that the function of receiver is realized
Provide feasibility.
Based on above-described embodiment, the present embodiment combination attached drawing, the choosing to the collection of simulant signal unit in above-described embodiment
Frequency module, which is made, to be illustrated, as shown in Fig. 2, the frequency-selecting module includes：The digital switch that is electrically connected with the frequency mixer and
The multiple low-pass filters being electrically connected with the digital switch；Wherein, each of the digital switch can be set in routing path
There are one low-pass filter, the intermediate-freuqncy signal is divided into multiple frequency ranges by the multiple low-pass filter；The digital switch root
According to described instruction by it is all can in routing path corresponding one can routing path connect.
It for the passband signal after being filtered, is followed by the 4th wideband radio frequency amplifier and processing is amplified to it, need
It is noted that the 4th wideband radio frequency amplifier is ADL5610.
The multiple low-pass filter is four, and the passband of four low-pass filters is respectively：0-200MHz, 0-
400MHz, 0-800MHz and 0-1500MHz.
The analog-to-digital conversion circuit system of a kind of radio telescope provided in this embodiment, by being filtered to intermediate-freuqncy signal
Processing so that the front-end circuitry can be applied to different observation needs, and passes through digital switch and select corresponding base band
Frequency range is exported so that the flexibility of the system is high.
Based on above-described embodiment, the present embodiment combination Fig. 2 says the clock module in collection of simulant signal unit
It is bright.The clock module, including：First voltage controlled oscillator and the second voltage controlled oscillator；First voltage controlled oscillator is described
Frequency mixer provides local oscillator, when second voltage controlled oscillator provides for the AD conversion unit and rear end FPGA circuitry system
Clock.
Specifically, which includes two voltage controlled oscillators, by adjusting two voltage controlled oscillators, realizes reliable
And adjustable clock output.It is more advantageous to whole system and reaches higher accuracy of timekeeping demand, so as to improve signal-obtaining
Bandwidth.
Based on above-described embodiment, the AD conversion unit further includes signal synchronization receiving module, and the signal synchronously connects
Module is received, for receiving the aerial signal of the 1pps.
The present embodiment passes through the setting signal synchronization receiving module in AD conversion unit so that whole system is realized same
Step.
The alternating expression modulus conversion chip is TI ADC12D1600 chips or AF201 chips.In the present embodiment, modulus
Converting unit uses the alternating expression modulus conversion chip ADC12D1600 that polylith bandwidth is 12bit for 3.2Gsps, precision, most
The sample rate of high 3.2GSPS meets the demand of the ultra wide band of FAST telescope receivers.
The TI ADC12D1600 chips include the ADC chips that two pieces of precision are 12bit.Each piece of precision is 12bit's
ADC chips are exported with 8 tunnels, and the TI ADC12D1600 chips are exported with 16 tunnels.
Since the sampling rate of ADC chips is significantly larger than the working frequency of rear end FPGA circuitry system, ADC chips
4 tunnels are further subdivided into four passages, are reduced per data rate all the way, are divided into the output of 16 circuit-switched datas.
In order to test the performance of ADC chips, it is 10MHz to give frequency input signal, and amplitude is 1.0VPP (crest voltage),
16 circuit-switched datas after obtained ADC chips are sampled merge into 4 tunnels, and Fig. 3 is to be surveyed according to ADC chips provided in an embodiment of the present invention
4 circuit-switched data waveform of time-domain signal and enlarged drawing are tried, four respective waveforms of passage as shown in Figure 3 are evenly distributed on entire model
In enclosing, without departing from full scale.Meanwhile four uniform weave in of road signal, it is seen that ADC chip operations are normal.
Then, 4 circuit-switched datas after synthesis are synthesized into 1 tunnel again.Fig. 4 is according to ADC chips provided in an embodiment of the present invention
Data waveform and enlarged drawing after time-domain signal merges are tested, as shown in figure 4, being combined into waveform all the way, Fig. 4 dotted lines are shown
2048 and -2048, the i.e. border of full scale sampling, the sample range of ADC chips is (- 2047~2048), it is seen that the letter of sampling
Number 1.0VPP is without departing from the maximum voltage value (1.2VPP or 5.5dBm) of ADC chip operations.
From the point of view of waveform amplification, there are 320 sampled points in each cycle, meets theoretical value, it is seen that sampled signal is rebuild good.
By 8 circuit-switched datas of derived FFT, data are handled using MATLAB, are one by 8 circuit-switched data cross-combinings
Road, first half (the 2048 points) mapping of 4096 points of selection cycle length, bandwidth 1.6GHz scopes.Fig. 5 is according to this hair
The schematic diagram of the actual measurement noise based on 156.25MHz signals that bright embodiment provides when theoretical reference value, as shown in figure 5, this
When input simple signal be 156.25MHz, 5dBm.
Calculating corresponding theoretical SNR value is
SNR=SNRADC+SNRFFT=52+10log (2048)=85dB
Ideal value is as shown in heavy line in figure, in comparison, the signal-to-noise ratio coincidence loss standard actually obtained.Entire system
System normal operation, hardware experiments work well.
In order to test hardware performance, take under the signal power of 0dBm, the signal of 24 different frequencies, calculated each frequency
Signal-to-noise ratio under rate point.Fig. 6 is with the change schematic diagram of frequency, such as Fig. 6 institutes according to signal strength provided in an embodiment of the present invention
Show, when 10MHz, signal-to-noise ratio 84dB, but gradually risen with the frequency of signal, under the signal-to-noise ratio of system is gradual
Drop, when signal frequency is 1.6GHz, signal-to-noise ratio 70dB, attenuation has reached 15dB.This is because sampling process, signal can be with
It the different of input frequency and SINC roll off is presented, be superimposed the effect of wave filter, cause such performance.This be meet it is pre-
Phase and design requirement.
Meanwhile under the signal frequency of 156.25MHz, the input signal of 14 different capacities has been selected, has been calculated each
The corresponding signal-to-noise ratio of a power points.Fig. 7 is to be shown according to ADC chips maximum linear input intensity provided in an embodiment of the present invention test
It is intended to, as shown in Figure 7, it is seen that when the power of signal is -30dBm, the signal-to-noise ratio of signal is 58dB, with the power of signal
Increase, the signal-to-noise ratio of signal linearly increases, and until 85dBm, and its corresponding power points is exactly the corresponding power of ADC maximum amplitudes
It is worth (1.2VPP or 5.5dBm), after the power of input signal is beyond maximum, ADC chip operation excess loads are presented non-
Linear response.This is the result is that meet estimated and design requirement.
To sum up, the analog-to-digital conversion circuit system of a kind of radio telescope provided by the invention makes full use of pressure point control to shake
Swing the flexibility that device (VCO) and numerical control rheostat are shown, select suitable passband, to frequency range globality, flexibly, efficiently
, it is necessary to digital frequency conversion coefficient stored in real-time update FPGA during control.It can be realized based on set of system multinomial
Receiver function and wave band keep flexibility, while cost is relatively low.So that digital display circuit flexibility is fully played,
Limit cooperation is realized with the noise attribute and frequency attribute of telescope and low noise amplifier.At this stage, many receiver meetings
It is built based on existing instrument and equipment, there is excessive volume, expense is higher, and fluctuation is bigger, lacks flexibility,
There is very big energy consumption, control has larger difficulty.All components are concentrated on the integrated circuit plate of 15cm*30cm,
Realize complete Digital Control.
Analog to digital conversion circuit unit is made using 12bit 3Gsps modulus conversion chips, and by FPGA compilation processes
In module optimization parallel realize unprecedented low-frequency ultra-wideband, the covering of high-precision frequency domain.In current American (such as
CASPER) in the analog to digital conversion circuit plate of all receivers, this be in same rate precision it is highest (while be also same precision, speed
Rate is most fast).By the progress of semiconductor technology, broadband receiver function development to a new step.
Finally, method of the invention is only preferable embodiment, is not intended to limit the scope of the present invention.It is all
Within the spirit and principles in the present invention, any modifications, equivalent replacements and improvements are made should be included in the protection of the present invention
Within the scope of.
Claims (10)
1. a kind of analog-to-digital conversion circuit system of radio telescope, which is characterized in that including collection of simulant signal unit and modulus
Converting unit；
Analog-digital conversion circuit as described system is located at the antenna of the radio telescope and the rear end FPGA electricity of the radio telescope
Between the system of road；
The collection of simulant signal unit, the radiofrequency signal for the antenna to be collected are amplified and are mixed, with generation
Meet the intermediate-freuqncy signal of the power requirement of the AD conversion unit；Also, it is extracted according to instruction corresponding in the intermediate-freuqncy signal
The IF passband signal of frequency range；It is additionally operable to provide clock for the AD conversion unit and the rear end FPGA circuitry system；
The AD conversion unit uses the alternating expression modulus conversion chip that polylith bandwidth is 12bit for 3.2Gsps, precision, uses
In the IF passband signal is converted to digital signal.
2. analog-to-digital conversion circuit system according to claim 1, which is characterized in that the collection of simulant signal unit bag
It includes：
Frequency mixing module, the radiofrequency signal for the antenna to be collected are amplified and are mixed, and generation meets the modulus and turns
Change the intermediate-freuqncy signal of the power requirement of unit；
Frequency-selecting module, for according to described instruction, extracting the IF passband signal of the corresponding band in the intermediate-freuqncy signal；
Clock module, for providing local oscillator for the frequency mixing module and being the AD conversion unit and the rear end FPGA
Circuit system provides clock；
Signal assist in synchronization module, for generating the aerial signal of 1pps so that analog-digital conversion circuit as described system, it is described after
FPGA circuitry system and the frequency stabilizer of signal assist in synchronization module binding is held to realize locking synchronization.
3. analog-to-digital conversion circuit system according to claim 2, which is characterized in that the frequency mixing module includes：It is electric successively
First low-noise amplifier of connection, the first fixed attenuator, the first wideband radio frequency amplifier, the first digital variable electrons decay
Device, the second fixed attenuator, the second wideband radio frequency amplifier, the 3rd fixed attenuator, the 3rd wideband radio frequency amplifier, the second number
Word variable electronic attenuator and frequency mixer.
4. analog-to-digital conversion circuit system according to claim 3, which is characterized in that the frequency-selecting module includes：With it is described
The digital switch of frequency mixer electrical connection and the multiple low-pass filters being electrically connected with the digital switch；Wherein, the number is opened
The each of pass can be set in routing path there are one low-pass filter, and the intermediate-freuqncy signal is divided by the multiple low-pass filter
Multiple frequency ranges；The digital switch according to described instruction by it is all can in routing path corresponding one can routing path connect.
5. A/D conversion system according to claim 4, which is characterized in that the multiple low-pass filter be four, four
The passband of a low-pass filter is respectively：0-200MHz, 0-400MHz, 0-800MHz and 0-1500MHz.
6. analog-to-digital conversion circuit system according to claim 3, which is characterized in that the clock module, including：First pressure
Control oscillator and the second voltage controlled oscillator；First voltage controlled oscillator provides local oscillator for the frequency mixer, and described second is voltage-controlled
Oscillator provides clock for the AD conversion unit and rear end FPGA circuitry system.
7. analog-to-digital conversion circuit system according to claim 2, which is characterized in that the AD conversion unit further includes letter
Number synchronous receiving module, the signal synchronization receiving module, for receiving the aerial signal of the 1pps.
8. analog-to-digital conversion circuit system according to claim 1, which is characterized in that the alternating expression modulus conversion chip is
TI ADC12D1600 chips or AF201 chips.
9. analog-to-digital conversion circuit system according to claim 8, which is characterized in that the TI ADC12D1600 chip bags
Include the ADC chips that two pieces of precision are 12bit.
10. analog-to-digital conversion circuit system according to claim 9, which is characterized in that the ADC that each piece of precision is 12bit
Chip is exported with 8 tunnels, and the TI ADC12D1600 chips are exported with 16 tunnels.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711433695.2A CN108063620A (en) | 2017-12-26 | 2017-12-26 | A kind of analog-to-digital conversion circuit system of radio telescope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711433695.2A CN108063620A (en) | 2017-12-26 | 2017-12-26 | A kind of analog-to-digital conversion circuit system of radio telescope |
Publications (1)
| Publication Number | Publication Date |
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| CN108063620A true CN108063620A (en) | 2018-05-22 |
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| CN108809343A (en) * | 2018-07-10 | 2018-11-13 | 山东大学 | Radio receiver system and the observation procedure for improving channel temporal resolution |
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