1. Current status of OCTAVE
Yusuke Kono1,
Tomoaki Oyama1, Noriyuki Kawaguchi1, Kotaro Niinuma2,
Kenta Fujisawa2, Hiroshi Takaba3, Kazuhiro Sorai4, Mamoru Sekido5, Shinobu Kurihara6, Yasuhiro Murata7
National Astronomical Observatory of Japan1,
Yamaguchi university2,Gifu university3, Hokkaido university4
NICT5, GSI6, JAXA7
My name is Yusue Kono from NAOJ. the title of my talk is Current status of OCTAVE

2. Contents OCTAVE Array OCTAVE Family EHT application
I’wll talk about our eVLBI array ,octave, and the instruments in the array.
Lastly we show an example of applications of OCTAVE technologies.

3. OCTAVE : Optically ConnecTed Array for Vlbi Exploration
eVLBI network in Japan
High sensitivity, on-the-fly result and low cost operation
The longest baseline is 1,300km
Hokkaido univ.
11m
JAXA
Usuda 64m*
Octave means ****.
There are many radio telescopes in Japan.
OCTAVE project is to connect some of them with broadband communication lines to carried out realtime VLBI obs.
feature of OCTAVE are High sensitivity, on-the-fly result and low cost operation except cost communication lines.
Four stations in orange color are connected and under operation.
Unfortunately, stations in blue were connected and are disconnected now. I will talk about this.
Yamaguchi univ.
32m
GSI Tsukuba
32m
Ibaraki Univ.*
32m x 2
NAOJ
NRO 45m*
NICT
Kashima 34m*
Gifu univ.
11m

4. Communication lines
Supplied by academic network (SINET4) and Test bed network (JGN-X)
10GbE to nodes
2x10GbE to Correlator at HQ of NAOJ in Tokyo
Kashima and Ibaraki are offline now. Trying to connect.
Usuda and NRO are offline now
Network configuration (Plan)
Local Recorders,
OCTADISK and K5,
are installed into
Usuda, NRO, Ibaraki and Tomakomai
for a while.
Com lines are supplied by Academic net SINET4 and test bed network JGN/Nict.
they provide a 10gbE port /station.
Kas and ibaraki are offline due to cross connection between them. I think problem will be solved soon.
Usds and NRO are also offline now. It is difficult to connect them for our budget.
We installed Local recorder in to them for while. we carried out post prcessing correlation. if offline stations were joined th observations.
OCTAVE is not only realtime VLBI array but also post processing array at this time.

5. Observation capability
X-band
Usuda64, Kashima34*, Yamaguchi32, Ibaraki32
MHz, BW512MHz x 1/2pols
K-band
NRO45, Kashima34*, Yamaguchi, Ibaraki32, Gifu11, Tomakomai11m
GHz, BW512MHz x 1/2pols
This shows Obs capabilitiy of OCTAVE
Two band obs are capabile.
one is Xband by Us…. band is fixed to 500MHz of a single or dual circular polarizations.
Kashima34* will be available if the network is connected.

6. Data processing and results
Image of 4C32.44
X-band, BW512 MHz, 4stations
software: AIPS
VLBI Detections of Parsec-Scale Nonthermal Jets in Radio-Loud Broad Absorption Line Quasars,
Doi et al., 2009
VLBI Observation of Fermi/LAT Un-associated Gamma-ray Sources, Niinuma et al.,2013
Science Obs. proposals are selected and operated by JVN(Japanese VLBI Network)
This is an example of image obtained by OCTAVE Xband. with 4 sta.
Left figure is image by VLBA the right is ours.
We can see two components as VLBA shows.
Needless to say, Imaging power is extreamly weaker than VLBA. But There are many thing to do by OCTAVE.
Doi et al categolized a lot of BAL quasers.
Niinuma etal made a follow up VLBI obsertvation of ganma ray sources after Felmi satellite observation.
Science Obs. proposals are selected and operated by JVN(Japanese VLBI Network)

7. International Observation
Recording and copying function at NAOJ/Tokyo
Fringe test with EAVN (East Asia VLBI Network)
September 2013, 14 stations
Fringe test with Noto
April 2013 K5
(NiCT)
Mark5B+
(Haystack)
OCTADISK
(NAOJ) DF
We join International VLBI obs.
HQ of NAOJ has various kinds of termnals such as K5, Mark5B, and OCTADISKour diskstrage module.
we can copy them with digital filtering.
EAVN team carried out first EAVN fringe test last month. OCTAVE copy system worked well.
Fringe test with noto in Italy was also carried out in April.

8. Octave family
We have developed several instruments for OCTAVE. We call them Octave family.
OCTAVIA
OCTAVe optIcal Adapter
OCTADISK
OCTAve Recorder
OCTACOR
OCTAve Correlator
OCTAD
OCTave ADc
OCTADIV
OCTAve DIVider
We have developed several instruments for OCTAVE. We call them Octave family.
Some of them act like gang of trouble/bug maker. they also members of the family.
Many non-OCTAVE family instruments are also used in the array,
such as ASD1000/3000, K5(NICT) and Mark5B(Haystack).

9. OCTAVIA (OCTAVe optIcal Adapter)
Converter between VSI and 10GbE
Electrical I/O
VSI-H 4 Ports
Total 8 Gbps
Optical I/O
10GbE
Protocol
VDIF/UDP/IP/10GbE
VSI
10GbE
ADC etc
OCTAVIA
Network
etc
VIA is a convertor between VSI and 10GbE. so VIA is a terminal adapter to network.
El. IO is VSIs upto 8Gbps. Optical IO is single 10GbE.the protocol is ….
Work by Dr Oyama (NAOJ)

10. OCTADISK DISK Recorder I/O Portable module
10GbE (up to 4Gbps)
Use with OCTAVIA
Portable module
12 HDDs /module
dedicated format.
Under Operation at the VERA stations.
OD is disk recorder IO is 10gBE.
It contains two portable disk modules
OD are installed into VERA stations and under operation.
Work by Dr Oyama (NAOJ)

11. OCTADISK2 OCTADISK2 is under development
Parts discontinuance of OCTADISK
COTS base, except Chassis
OS:Linux, Linux file system
Portable module
same to OCTADISK
Prototype
We developing OD2 now, because of patrs discontinuance of OCTADISK.
Parts discontinuance is a important problem for us.
Any way we have to continue OD that are already installed into vera by developing OD2.
OD2 is COTSbase exxcept shassis.
os is linuxx and data are recorded on linux file sysmtem.
This is a figure of proto type of OD2. tye are perfectly COTS by using desktop PCs.
“Perfect COTS”
Work by Mr Suzuki and Dr Oyama (NAOJ)

12. OCTAVIA/DISK in KJCC NAOJ supplied Raw VLBI Data Buffer to KJCC
VSI Input
from various
terminals
Storage
on HDD
output
Synchronized
data to VCS
Origin of OCTAVIA and OCTADISK

13. Correlators for OCTAVE
Real time correlator
FPGA correlator
FX and XF type
2Gbps/station
Post processing correlator
Software correlator
Engine(GICO3) by NICT
Integration by NAOJ with NICT
Work by Dr Oyama (NAOJ)
Soft Correlators Hard Correlators

14. OCTAD (ADC) Direct RF sampling Wide bandwidth
22GHz (43GHz, under test)
Wide bandwidth
8.192Gsps-3bit
use with a RF band pass filter
For next generation VERA system
Wideband observation enable us to use weaker and closer reference sources of dVLBI astrometry

15. OCTAD Lab. test of sampling jitter Fringe test observation
0.17 psec (Lc<1% @43GHz)
Fringe test observation
Mizusawa 10m x 20m BL=60m
16Gbps x 2 OCTAD
Jitter　0.17psec
Lc <1%
PI: Dr Oyama (NAOJ)

16. Upgraded OCTAD We add two functions DBBC
Backward compatibility
BW:16MHz~2048MHz/ch
External AD module up to 50GHz
V-connector
Direct receiving
50GHzModule

17. Telescopes and Phasing
EHT / ALMA Phasing
Event Horizon Telescope
Japanese contribution
Data transfer from AOS to OFS
AOS: Telescope site
OSF: Operations Support Facility
64Gbps(8Gbps x8ch)
A single dark fiber
Design started at 2011.
Telescopes and Phasing
Optical link km
VLBI Recorder
Storage Transfer and Correlation
PI: Prof. Honma (NAOJ)

18. EHT / ALMA Phasing WDM of 16 wavelengths by 10GbE-ZR XFP OFS AOS PIC
XFP –ZR
lambda1
AWG1
AWG1
XFP –ZR
lambda2
XFP
REC
AWG2
AWG2
PIC
XFP
XFP –ZR
lambda3
AWG3
AWG3
XFP –ZR
lambda4
XFP
REC
AWG4
AWG4
PIC
XFP
XFP –ZR
lambda5
AWG5
AWG5
XFP –ZR
lambda6
XFP
REC
AWG6
AWG6
PIC
XFP
XFP –ZR
lambda7
AWG7
AWG7
XFP –ZR
lambda8
XFP
REC
AWG8
AWG8
PIC
XFP
XFP –ZR
lambda9
AWG9
AWG9
XFP –ZR
lambda10
XFP
REC
AWG10
AWG10
ZR with ITUT wavelength selection 900,000 yen x18 =16,200,000 yen
10 Gigabit Small Form Factor Pluggable
10GBASE-SR (Short Reach) m
PIC
XFP
XFP –ZR
lambda11
AWG11
AWG11
XFP –ZR
lambda12
XFP
REC
AWG12
AWG12
PIC
XFP
XFP –ZR
lambda13
AWG13
AWG13
XFP –ZR
lambda14
XFP
REC
AWG14
AWG14
PIC
XFP
XFP –ZR
lambda15
AWG15
AWG15
XFP –ZR
lambda16
XFP
REC
AWG16
AWG16
Monitor
Power
Power
Monitor
Power
Power
Moni.
(Ethernet)

19. EHT / ALMA Phasing OFL (Opical Fiber Link) NAOJ/Elecs corp.
High Cost performance
“Error Free” is confirmed
OFLs for AOS and OSF
optical attenuator
Expected Attenuation between AOS and OFS
OFL at Haystack

20. Summary Introduction of Octave and Octave family
Application of OCTAVE technology to EHT/WDM

21. backup

22. Jitter measurement Synchronized SG input Phase are extracted by FFT
GOD SG AD
storage
input SG
CLK
DIST
FFT
FFT
FFT
Synchronized SG input
Phase are extracted by FFT
・・・

23. Phase fluctuations 18.424GHz 14.328GHz 10.232GHz 6.136GHz 2.040GHz
Time (sec)

24. Phase rms and jitter
Linear fitting
Φrms=2πｆδT+σ
JitterδT
0.17psec

25. Allan standard deviation
VSOP- 2 SPEC.
ASD
（WPM－45GHz Lc 1% ）