Subversion Repositories svnkaklik

Rev

Details | Last modification | View Log

Rev Author Line No. Line
1073 kaklik 1
\chap Testing construction
2
 
3
\sec Required parameters
4
 
5
Wide dynamical range and high  3 intercept point are desired. The receiver must accept wide dynamic signals because radioastronomical signal in typically weak signal covered by strong man made noise signal.    
6
 
7
%\sec Sampling frequency
8
 
9
%\sec System scalability
10
 
11
%\secc Differential signaling 
12
 
13
\sec System description
14
 
15
%	\secc Frequency synthesis       
16
 
17
\secc Signal connectors 
18
 
19
Several widely used and commercially easily accessible differential connectors was considered. 
20
 
21
\begitems
22
 
23
  * <del>[[http://en.wikipedia.org/wiki/Hdmi|HDMI]]</del>
24
  * [[http://en.wikipedia.org/wiki/Serial_attached_SCSI#Connectors|SAS]]/[[http://en.wikipedia.org/wiki/Serial_ATA|SATA]]
25
  * <del>[[http://en.wikipedia.org/wiki/Display_port|DisplayPort]]</del>
26
 
27
\enditems
28
 
29
MiniSAS connector was chosen as  the best for use in connection multiple ADC modules.  This miniSAS connector is compatible with existing SATA cabling system. Translation between SATA and miniSAS is achieved by SAS to SATA adapter cable. This cable is used in servers to connecting SAS controller to multiple SATA hard disc in RAID systems. 
30
 
31
\secc Design of ADC modules
32
 
33
For PCB layout KiCAD design suite was used. Used version has the CERN Push \& Shove routing capability integrated but was slightly unstable and sometimes falls on exception during routing. Design must be often saved due to this stability issues. But Open-source KiCAD works well compared to commercial solutions as MentorGraphics PADS or Cadence Orcad.  
34
 
35
 
36
 
37
 
38
\secc ADC modules interface
39
 
40
All two ADCdual01A modules was connected to FPGA ML605 board trough
41
 
42
 
43
\midinsert
44
\picw=10cm \cinspic ./img/ML605-board.jpg
45
\caption/f Used FPGA ML605 development board.
46
\endinsert
47
 
48
 
49
 
50
\secc Output data format
51
 
52
\midinsert
53
\ctable {cccccccccc}{
54
\hfil
55
 & \multispan9 \hfil 160bit packet \hfil \crl \tskip4pt
56
Data name &  FRAME  & \multispan2 \hfil ADC1 CH1 \hfil & \multispan2 \hfil ADC1 CH2 \hfil & \multispan2  \hfil ADC2 CH1 \hfil & \multispan2 \hfil ADC2 CH2 \hfil  \cr
57
Data type & uint32 & int16 & int16 & int16 & int16 & int16 & int16 & int16 & int16 \cr
58
Content & saw signal & $t1$ &  $t_{1+1}$ &  $t1$ &  $t_{1+1}$ &  $t1$ &  $t_{1+1}$ &  $t1$ &  $t_{1+1}$ \cr
59
}
60
\caption/t System device "/dev/xillybus_data2_r" data format
61
\endinsert
62
 
63
\sec Achieved parameters
64
 
65
\secc Data reading and recording 
66
 
67
For reading data stream from ADC driver Gnuradio software was used. Gnuradio suite consist gnuradio-companion which is a graphical tool for creating signal flow graphs and generating flow-graph source code. This tool was used to create basic RAW data grabber to record and interactive wiev data stream output from ADC modules. 
68
 
69
\midinsert
70
\picw=15cm \cinspic ./img/screenshots/Grabber.grc.png
71
\caption/f ADC recorder flow graph created in gnuradio-companion.
72
\endinsert
73
 
74
\midinsert
75
\picw=15cm \cinspic ./img/screenshots/Grabber_running.png
76
\caption/f User interface window of running ADC grabber.
77
\endinsert
78
 
79
Interactive graber wiewer user interface shows live osciloscope-like time-value display for all data channels and live time-frequency scrolling display (waterfall wiev) for displaying frequency components of grabbed signal. 
80
 
81
 
82
%\sec Future improvements
83
 
84
%\chap Example of usage
85
 
86
%\sec Simple polarimeter station
87
 
88
%\sec Basic interferometer station
89
 
90
%\sec Simple passive Doppler radar
91
 
92
%\chap Proposed final system
93
 
94
%\sec Custom design of FPGA board
95
 
96
%\sec Parralella board computer
97
 
98
%\chap Conclusion