/dokumenty/skolni/diplomka/appendix.tex |
---|
18,12 → 18,12 |
\centerline {\kern\ht0 \pdfsave\pdfrotate{90}\rlap{\box0}\pdfrestore} |
} |
\app Thesis specification |
%\app Thesis specification |
\break |
\picw=\hsize % obrázek na šířku sazby |
\cinspic ./img/zadani.jpg |
\nextoddpage |
%\break |
%\picw=\hsize % obrázek na šířku sazby |
%\cinspic ./img/zadani.jpg |
%\nextoddpage |
\app Circuit diagram of ADCdual01A module |
38,13 → 38,23 |
\app Content of enclosed CD |
\begitems |
% zdrojove soubory prace |
* Thesis source code |
% referencni datovy soubor s navzorkovanymi daty |
* Measured data file from interferometric station |
% instalacni soubor pro pouzitou verzi gnuradia |
* Installation file of gnuradio in version used in work |
% pouzite GRG flow grafy |
* GRC flow-graphs |
% datasheety |
* Used datasheets |
% fotografie z vyvoje a mereni ADC. |
* Photographs from development and testing |
* Source files for designed PCB modules. |
\enditems |
/dokumenty/skolni/diplomka/conclusion.tex |
---|
1,25 → 1,18 |
\chap Conclusion |
Special design of scalable data-aquisition system was proposed. This system has parameters |
Special design of scalable data-acquisition system was proposed. This system has unique parameters compared to state of the art radioastronomy signal processing hardware. Offered 16bit resolution and related dynamical range is more than other similar constructions could offer. We demonstrated system working on the most basic interferometric station. Other validation of reached parameters should be needed. After that, the final design will eventually become a part of MLAB Advanced Radio Astronomy System\cite[mlab-aras]. |
The final design will eventually become a part of MLAB Advanced Radio Astronomy System. |
All requirements demanding by specification have been reached or exceed. The required minimal sampling frequency 1 MHz has been exceeded fifth times at least. Requested dynamical range specified by 12 bit have been exceeded at least by 8 dB in decibel scale. As by-pass product of digitalisation unit design the software defined GPS disciplined oscillator device has been developed. This device is currently in use in several radio meteor detection station in Czech Republic. |
On other hand the proposed design is not still perfect and some minor imperfections should be corrected in future work. |
\sec Possible hardware improvements |
The PCB design of the used modules might need more precise high-speed optimalization of differential pairs. Improvement in high-speed routing allows a possible use of the fastest ADC from the Linear Technology devices family. The use of the faster ADCs even improve a range of possible usages. |
The PCB design of the used modules might need more precise high-speed optimization of differential pairs. Improvement in high-speed routing allows a possible use of the fastest ADC from the Linear Technology devices family. The use of the faster ADCs even improve a range of possible usages. Minor ADC module imperfections, such as the unnecessary separation of FRAME and DCO signal to two connectors, should be mitigated. These two signals should be merged together to one SATA connector. With this modification we are able to remove one redundant SATA cable between the analog to digital converter device and between computational unit section. |
\secc ADC modules weakness |
Several ADC module imperfections, such as the unnecessary separation of FRAME and DCO signal to two connectors, should be mitigated. These two signals should be merged together to one SATA connector. With this modification we are able to remove one redundant SATA cable between the analog to digital converter nest and between computational unit nest. |
\sec Possible software improvements |
In the future versions of the device, the Xillybus IP core and interface should be swapped with an open-source alternative PCIe interfacing module or PCIe might be completely avoided. |
In the future versions of the system hardware, the Xillybus IP core and driver interface should be swapped with an open-source alternative of PCIe interfacing module or PCIe might be completely avoided. In ADC configuration FPGA module, the SPI configuration data registers read back should be implemented. |
SPI configuration data read back should be implemented. |
\bibchap |
\usebbl/c mybase |
/dokumenty/skolni/diplomka/description.tex |
---|
1,7 → 1,16 |
\chap Trial design |
\chap Trial design implementation |
The whole design of radioastronomy receiver digitalization unit is constructed to be used in a wide range of applications and tasks related to digitalization of signal from radioastronomy receivers. A good illustrating problem for its use is a signal digitalisation from multiple antenna arrays. |
\midinsert |
\clabel[expected-block-schematic]{Expected system block schematic} |
\picw=\pdfpagewidth \setbox0=\hbox{\inspic ./img/Coherent_UHF_SDR_receiver.png } |
\par\nobreak \vskip\wd0 \vskip-\ht0 |
\centerline {\kern\ht0 \pdfsave\pdfrotate{90}\rlap{\box0}\pdfrestore} |
\caption/f Expected realisation of signal digitalisation unit. |
\endinsert |
\sec Required parameters |
We require following technical parameter, to supersede existing digitalization units solutions. |
113,9 → 122,9 |
\midinsert |
\clabel[adcdual-preview]{Preview of designed ADCdual PCB} |
\picw=10cm \cinspic ./img/ADCdual_Top.png |
\picw=10cm \cinspic ./img/ADCdual_Bottom.png |
\caption/f Modelled previews of designed and realised PCB of ADCdual01A modules. Differential pairs routing are clearly visible. |
\picw=10cm \cinspic ./img/ADCdual01A_Top_Big.JPG |
\picw=10cm \cinspic ./img/ADCdual01A_Bottom_Big.JPG |
\caption/f Realised PCB of ADCdual01A modules. Differential pairs routing are clearly visible. |
\endinsert |
\secc ADC selection |
185,9 → 194,9 |
\secc ADC modules interface |
\midinsert |
\picw=10cm \cinspic ./img/FMC2DIFF_top.png |
\picw=10cm \cinspic ./img/FMC2DIFF_Bottom.png |
\caption/f Modelled prewievs of designed and realised PCB of FMC2DIFF01A module. |
\picw=10cm \cinspic ./img/FMC2DIFF_Top_Big.JPG |
\picw=10cm \cinspic ./img/FMC2DIFF_Bottom_Big.JPG |
\caption/f Realised PCB of FMC2DIFF01A module. |
\endinsert |
Both of the ADCdual01A modules were connected to FPGA ML605 board trough FMC2DIFF01A adapter board. The design of this adapter expects the presence of FMC LPC connector on host side and the board is, at the same time, not compatible with MLAB. It is, on the other hand, designed to meet the VITA 57 standard specifications for boards which support region 1 and region 3. VITA 57 regions are explained in the picture \ref[VITA57-regions]. |
321,11 → 330,11 |
The interactive grabber-viewer user interface shows live oscilloscope-like time-value display for all data channels and live time-frequency scrolling display (a waterfall view) for displaying the frequency components of the grabbed signal. Signal is grabbed to file with exactly the same format, as it is described in table \ref[xillybus-interface]. |
\sec Achieved parameters |
\chap Achieved parameters |
Trial design construction was tested for proper handling of sampling rates in range of 5 MSPS to 15 MSPS it should work above this limit. System works on i7 8 cores computer with Ubuntu 12.04 LTS operating system. Data recording of input signal is impossible above sampling rates around 7 MSPS due to bottleneck at HDD speed limits, it should be resolved by use of SSD disk drive. But it is not tested in our setup. |
\secc ADC module parameters |
\sec Measured parameters |
Two prototypes of ADC modules were assembled and tested. The first prototype, labeled ADC1, has LTC2190 ADC chip populated with LT6600-5 front-end operational amplifier. It also has a 1kOhm resistors populated on inputs which give it an ability of an internal attenuation of the input signal. The value of this attenuation $A$ is described by the following formula \ref[ADC1-gain] |
342,9 → 351,13 |
\enditems |
We have $R_2 = 1000 \Omega$ and $R_1 = 50 \Omega$ which imply that $A = 0.815$. That value of A is further confirmed by the measurement. |
In our measurement setup we have H1012 Ethernet transformer connected to inputs of ADC. We have used this transformer for signal symetrization from BNC connector at Agilent 33220A signal generator. Circuit diagram of used transformer circuit is shown in picture and circuit realization in photograph \ref[SMA2SATA-nest]. |
In our measurement setup we have H1012 Ethernet transformer connected to inputs of ADC. We have used this transformer for signal symetrization from BNC connector at Agilent 33220A signal generator. Circuit diagram of used transformer circuit is shown in picture \ref[balun-circuit] and circuit realization in photograph \ref[SMA2SATA-nest]. |
% doplnit schema zapojeni transformatoru. |
\midinsert |
\clabel[balun-circuit]{Balun transformer circuit} |
\picw=10cm \cinspic ./img/SMA2SATA.pdf |
\caption/f Simplified balun transformer circuit diagram. |
\endinsert |
The signal generator Agilent 33220A which we used does not have optimal parameters for this type of dynamic range measurement. Signal distortion and spurious levels are only -70 dBc according to Agilent datasheet \cite[33220A-generator]. We have managed to measure an ADC saturation voltage of 705.7 mV (generator output) with this setup, mostly due to an impedance mismatch and uncalibrated measurement setup, with 1V ADC range selected by sense pin. This is a relatively large error, but the main result of our measurement, seen as a FFT plot shown in image \ref[ADC1-FFT], confirms $>$80 dB dynamic range at ADC module input. |
385,11 → 398,11 |
\chap Example of usage |
\sec Example of usage |
For additional validation of system characteristics a receiver setup has been constructed. |
\sec Basic interferometric station |
\secc Basic interferometric station |
Interferometry station was chosen to serve as the most basic experimental setup. We connected the new data acquisition system to two SDRX01B receivers. Block schematics of the setup used is shown in image \ref[block-schematic]. Two ground-plane antennae were used and mounted outside the balcony at CTU building at location 50$^\circ$ 4' 36.102'' N, 14$^\circ$ 25' 4.170'' E. |
Antennae were equipped by LNA01A amplifiers. All coaxial cables have the same length of 5 meters. Antennae were isolated by common mode ferrite bead mounted on cable to minimise the signal coupling between antennas. Evaluation system consists of SDGPSDO local oscillator subsystem used to tune the local oscillator frequency. |
396,7 → 409,7 |
\midinsert |
\clabel[block-schematic]{Receiver block schematic} |
\picw=\pdfpagewidth \setbox0=\hbox{\inspic ./img/Coherent_UHF_SDR_receiver.png } |
\picw=\pdfpagewidth \setbox0=\hbox{\inspic ./img/Basic_interferometer.png } |
\par\nobreak \vskip\wd0 \vskip-\ht0 |
\centerline {\kern\ht0 \pdfsave\pdfrotate{90}\rlap{\box0}\pdfrestore} |
\caption/f Complete receiver block schematic of dual antenna interferometric station. |
424,10 → 437,15 |
For the simplest demonstration of phase difference between antennae, we have analysed part of the signal by complex conjugate multiplication between channels. Results of this analysis can be seen in the following picture \ref[phase-difference]. Points of the selected part of signal create a clear vector, which illustrates the presence of the phase difference. |
%\sec Simple passive Doppler radar |
\secc Simple passive Doppler radar |
%\sec Simple polarimeter station |
% doplnit popis |
\secc Simple polarimeter station |
% doplnit popis |
\chap Proposition of the final system |
The construction of a final system, that is supposed to be employed for real radioastronomy observations will be described in this chapter. It is mainly a theoretical analysis of the data handling systems. Realization of the described ideas might be possible as a part of our future development after we fully evaluate and test the current trial design. |
465,7 → 483,7 |
\midinsert |
\clabel[img-NVIDIA-K1]{NVIDIA Jetson TK1 Development Kit} |
\picw=15cm \cinspic ./img/Jetson_TK1_575px.jpg |
\caption/f The NVIDIA Jetson TK1 Development Kit \url{https://developer.nvidia.com/jetson-tk1}. |
\caption/f The NVIDIA Jetson TK1 Development Kit \cite[nvidia-k1]. |
\endinsert |
NVIDIA board differs from other boards in its category by a presence of PCI Experess connector. If we decide to use this development board in our radio astronomy digitalisation system, the PCI express should be used for FPGA connection. A new FPGA board with PCI Express direct PCB connector |
/dokumenty/skolni/diplomka/diplomka.pdf |
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30,13 → 30,16 |
%\subtitleEN {the plain\TeX{} template for theses at CTU} |
% If minor language is other than English |
% use \titleCZ, \subtitleCZ or \titleSK, \subtitleSK instead it. |
\pagetwo {} % The text printed on the page 2 at the bottom. |
%\pagetwo {} % The text printed on the page 2 at the bottom. |
\specification {\picw=\hsize \cinspic ./img/zadani.jpg } |
\abstractEN { |
. |
} |
\abstractCZ { |
. |
Aktuální radioastronomická pozorovnání jsou dnes z důvodu existence rušení a potřeby získat velké úhlové rozlišení realizována jako multi anténní přijímací systémy. Takto konstruovaná zařízení mají ale značné nároky kvalitu zpracování signálu z více kanálů. V této práci je navržena možná realizace digitalizační části takového přijímače. Popsaná realizace je optimalizována na vysoký dynamický rozsah vstupních signálů a dobrou fázovou stabilitu, což jsou nejvýznamnější parametry pro použítí ve více anténních systémech. Konstrukce je koncipována jako open-source hardware řešení, které má zatím jedinnečné parametry v oblasti přístrojů určených pro amatérskou i profesionální radioastronomii. |
} % If your language is Slovak use \abstractSK instead \abstractCZ |
\keywordsEN { ADC interface, radioastronomy, signal digitalisation |
60,7 → 63,7 |
%%%%% <-- % The place for your own macros is here. |
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%\draft % Uncomment this if the version of your document is working only. |
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/dokumenty/skolni/diplomka/introduction.tex |
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16,7 → 16,7 |
From the above mentioned facts concerning the natural radio signals we can conclude that modern requirements imposed on a radioastronomy receiver are completely different from the requirements existing back in the history. Radioastronomy is no longer limited by an access to electronic components, today it is rather limited by the everywhere presence of electronic. |
\sec Modern Radio astronomy receiver |
\sec Radio astronomy receiver |
In the beginnings of radioastronomy, the receivers were constructed as simple stations with single antenna or multi antenna array with fixed phasing. This approach was used because of the existing limits of electronic components and technologies. The main challenges of those times were the problem of noise number and low sensitivity, both present due to the poor characteristics of active electronic components such as transistors and vacuum tubes. |
28,18 → 28,6 |
New radio astronomy systems such LOFAR are explicit examples of the scalability and redundancy approach. LOFAR has completely different and novel structure developed to solve the problems of radioastronomy signal reception. It exclusively uses multi antenna arrays and mathematical algorithms for signal handling. Radio signals recorded by LOFAR can be used in multiple ways: radio images can be computed (if sufficient cover of u/v plane is achieved), radiation intensity can be measured, spectrum can be analysed for velocity measurement, etc. |
\secc Observation types |
Current radioastronomy knows several types of observations. |
\begitems |
* Spectral observations |
* Intensity observations |
* Velocity observations |
\enditems |
All of them prefer high frequency resolution and stability. Wide observation bandwidth in hundreds of MHz is usually desirable for easier differentiation of source types. |
\sec Required receiver parameters |
The novel approach of receiver construction described above goes hand-in-hand with new requirements on receiver parameters as well. Currently no additional attempts to improve the signal-to-noise ratio on single antenna are performed. There are however other parameters requested nowadays. |
83,7 → 71,7 |
Historically, the parameter of bandwidth in radioastronomical receiver used to be within the kilohertz range. Small bandwidth was acceptable because observations were processed directly by listening or by paper chart intensity recorder. Chart recorder integrated energy of signal over defined small bandwidth which was suitable for detecting the intensity variance of microwave background. No wide-band transmitters existed in that era (except for TV transmitters) and tuning to other neighbouring frequency was easy as they were mostly vacant. Parallel observations from several places were unnecessary as well because the electromagnetic conditions were nearly same at all locations. |
\sec Current status of receivers digitalization units |
\sec State of the art receivers digitalization units |
Only few digitalization systems dedicated for radioastronomy currently exists. Currently existing systems uses either custom design of whole receiver or they are constructed from commercially available components. Open-source principle attempts are very rare in radioastronomy field. |
/dokumenty/skolni/diplomka/mybase.bbl |
---|
117,6 → 117,10 |
\newblock Microsoft spectrum observatory, 2012. |
\newblock \url{http://observatory.microsoftspectrum.com/}. |
\bibitem{mlab-aras} |
Jakub~Kákona MLAB. |
\newblock Pokročilá radioastronomická stanice aras01a, September 2013. |
\bibitem{thunderbolt-chips} |
Intel Mouser. |
\newblock Dsl2210, January 2014. |
123,6 → 127,11 |
\newblock |
\url{http://cz.mouser.com/search/Refine.aspx?Keyword=106790692&Ns=Pricing|0&FS=True&Ntk=P_MarCom}. |
\bibitem{nvidia-k1} |
NVIDIA. |
\newblock The nvidia jetson tk1 development kit, April 2014. |
\newblock \url{https://developer.nvidia.com/jetson-tk1}. |
\bibitem{casper-project} |
Univeristy of~California~Berkeley. |
\newblock Center for astronomy signal processing and electronics research, May |
/dokumenty/skolni/diplomka/mybase.bib |
---|
206,4 → 206,18 |
URLDATE= {2014-5-4}, |
} |
@MISC{mlab-aras, |
AUTHOR = {MLAB, Jakub Kákona}, |
TITLE = {Pokročilá radioastronomická stanice ARAS01A}, |
YEAR = {2013}, |
MONTH = Sep 11, |
NOTE = {\url{http://wiki.mlab.cz/doku.php?id=cs:aras}}, |
} |
@MISC{nvidia-k1, |
AUTHOR = {NVIDIA}, |
TITLE = {The NVIDIA Jetson TK1 Development Kit}, |
YEAR = {2014}, |
MONTH = Apr, |
NOTE = {\url{https://developer.nvidia.com/jetson-tk1}}, |
} |