vdif (vlbi data interchange format) as a common data format in e-vlbi era. m. sekido (nict)...
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VDIF(VLBI Data Interchange Format) as a common data
format in e-VLBI era.
M. Sekido (NICT)M.Kettenis(ATNF), C.Phillips(JIVE),
A.Whitney(MIT/Haystack),Y.Koyama(NICT), H.Harai(NICT)
East-Asia VLBI Workshop 18 Mar. 2009 @ Korea
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Compatibility between VLBI systems has been a headache issue for a long time.
K3,Mark3,VLBA
K4,VSOP
S2
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Standard interface:VSI-H, VSI-S, VSI-E
Sam
ple
r
DIM DOM
VSI-H VSI-H
VSI-S
VSI-EVSI-E
Co
rrelator
E-VLBI
VSI-HVSI-H
RTP/RTCP
ADS1000
Mark5B
VOA-200 VOA-200
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Network
eVLBI: Data transport media has replaced by HDD/network.
Mark5B
Correlation Agent(Cor_srv2.pl)Correlation Agent
(Cor_srv2.pl)Correlation Agent(Cor_srv2.pl)Correlation Agent
(Cor_srv2.pl)
Network
K5
Mk5
Correlators:Soft/Hard
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Standard Data format (VDIF)
Discussion in eVLBI WS@Shanghai(2008)
Task Force member (A.Whitney, M.Kettenis, C.Phillips, M.Sekido) as regional representatives have discussed by E-mail.
Asia( NICT)
Asia( NICT)
Australia(ATNF)
Australia(ATNF)
USA(Haystack)
USA(Haystack)
Europe(JIVE)
Europe(JIVE)
VDIFTask Force
VDIFTask Force
VDIFVDIF
SHAO NAOJ KA 냐
NRAO
EVN
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”standardized transport-independent VLBI data-interchange format that is suitable for all types of VLBI data transfer, including real-time and near-real-time e-VLBI, as well as disk-file storage.”
VDIF
Protocol ( TCP/IP,UDP/IP, etc…,data file) is not defined, this time. You can use any…
Data format (contents in frames) is defined
DAS Correlator
32b
it/word
Data
Header
Data
Header
Data
Header
Basic Structure = Frame format
VDIFVDIF
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Possible Usage of VDIF:
File File
D H D H D H D H D H D H
FTP,HTTP,Tsunami,or any otherD H D H D H
single stream of Multi-channel data
VDIFVDIF
Multi (single-channel) streams to different destinations
D HD HD H
D HD HD H
D HD HD H
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Header FormatInvalid flag Legacy
mode:16byte or 32byte header
Half Year Counter since 2000.0
Sequencial #Frame
Frame size
Complex flag
Version No.
Extended Version
Bit
Nch
ID for multi-stream
Station ID
User Defined header field
VDIFVDIF
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Data format1bit/sample
2bit/sample
3bit/sample
4bit/sample
VDIFVDIF
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Data format (Complex data)
1bit/sample
2bit/sample
3bit/sample
4bit/sample
VDIFVDIF
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VDIF Data Stream Format Designator
1024-16-2-1 ⇒ 32Msps-2bit-16ch 1024-16-2-4 ⇒ 32Msps-2bit-16ch
via 4ch-4 streams
VDIFVDIF
threads#Bit/Samplech# TotalRate Data Total
2Designator1Designator
1024-16-2+64-8-8 ⇒ 32Msps-2bit-16ch stream + 1Msps-8bit-8ch
stream
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Summary
VDIF has a scope of Transport Independent Standard VLBI
Data Format Wide Flexibility for VLBI Applications
(Geodesy, Astronomy, Spacecraft) Multi stream for distributed processing
Standard Transport Protocol may be discussed in the next.
VDIFVDIF