Possible Engineering Support for Dual Polarization and Ultra Wide

Band Observation with EAVN N. Kawaguchi

National Astronomical Observatory

East Asia VLBI Meeting@SeoulMarch 18, 2009

Importance of Dual Pol. Observation

• Polarization Imaging– Distribution of magnetic field around an AGN core

and a jet is extremely important to understand radio emission from AGN.

• Highly Sensitive Maser Observation– Only possible solution to have better sensitivity in

observing maser sources is to observe in both polarization, larger bandwidth is not effective for better SNR not like as an observation of a continuum source.

Importance of UWB Observation

• Highly Sensitive Continuum Observation– Square root 2 better sensitivity we can enjoy in a

continuum observation on twice wide bandwidth.– We need high sensitivity to detect correlation

between cross polarized signals.• Better Delay Resolution in Geodetic VLBI– Twice larger bandwidth produces twice better delay

observations, and gives better accuracy in a geodetic VLBI solution.

• Better Sensitivity in Faraday Rotation Measure

Talks today

• Brief Summary of the status of Japanese stations

• Dual Polarization Receiving System to be implemented in VERA

• Experimental results of a X-pol observation recently performed with real time eVLBI connection at a speed of 2G-bps and recording on disks for off-line processing

• Correlation Support

Japanese StationsStation Frequency Dual Polarization

CapabilityeVLBI

Connectivity

Tomakomai 11m 22G Planned Planned in 2009

VERA Mizusawa 20m 2, 6.7, 8, 22, 43G Planned in 2009 in 22G Not connected

Ibaraki 32m x 2 6.7, 8, 22G Planned in 2009 and after Planned in 2009

Kashima 34m 2, 8, 22, 43G Possible in 8G Connected

Tsukuba 32m 2, 8, 22G Possible in 8, 22G Connected

Usuda 64m 2, 8G Planned in 8G Not Connected

Nobeyama 45m 22, 43G Possible in 22, 43G Not Connected

Gifu 11m 22G Planned Connected

Yamaguchi 32m 6.7, 8, 22G Possible in 8, 22G Connected

VERA Iriki 20m 2, 6.7, 8, 22, 43G Planned in 22G Not Connected

VERA Ishigaki 20m 2, 6.7, 8, 22, 43G Planned in 22G Not Connected

VERA Ogasawara 20m 2, 6.7, 8, 22, 43G Planned in 22G Not Connected

Dual Polarization Receiver of VERAMinimum Implementation Plan

2 Freq.D/C

2 Freq.D/C

D/C

4:2

IF S

elec

tor

MethanolReceiver

2 channelBBC

ADS-1000

ADS-1000

Beam A Beam B

22G 43G 22G 43G

LO

5-7G 5-7G

5-7G

6.7G

R L L L L

Real time X-pol eVLBI Detection

016Day, 2009 on 3C454.3

Real time detection and off-line processing of data archived on disks at a data rate of 2Gbps were successfully done.

Wideband Recorder in VLBI

Unit Recording Media Data Rate Storage Capacity*

DIR-1000 Magnetic Tape 1Gbps 80 minutes

Mark-Vb Removable 8 HDDs 1Gbps 27 Hours

FDR-1000 Removal 12 HDDs 2Gbps 20 Hours

Mark-Vc Removable 8 HDDs 4Gbps 13 Hours

K5 （ ADS-3000+PC-VSI) Fixed 　 HDDs 4Gbps 17 Hours**

RVDB Fixed 24 HDDs 8Gbps 40 hours* 1.5 TB HDD except for K5 is assumed.** Deliverer’s anouncement

Gigabit Data Recorder in the world

Outlook of FDR-1000 installed in VERA Mizusawa Station

VSI I/F(VERA Terminal)

FDR-1000

I/O Box2Gbps x 1ch1Gbps x 2ch

Disk Cartridge(12HDD x 2)

ADS3000 + PC-VSI Recorder

4096Mbps　recording　for　 １７ hours

Generalized 10GigE Data Distribution Concept

ChannelizedEthernet packets

10GigE

DBE4　x　1000MHz

IF

DBE

10GigE

Station　1PPS

H-maser　5/10MHz

Standard10GigESwitch

Mark　5C

4　x　1000MHzIF

8　Gbps

10GigE8　Gbps

10GigE8　Gbps

10GigE8　Gbps

4　Gbps

10GigE4　Gbps

10GigE4　Gbps

Mark　5C

Mark　5C

dBBC/DBE/VDBE

dBBC/DBE/VDBE

MK-Vc

Configuration　of　an　RVDB　base　unit

VSI　I/F　Unit(DIO)

Disc　Unit(DDB)

Disc　Unit(DDB)

10GbE　S

witch

ing　　Hub

VDB-2000　system　(One　I/F　unit　and　four　disc　units)

I/O　data　rate　is2048　Mbpseach

Disc　Unit(DDB)

Disc　Unit(DDB)

D　Port

C　Port

D　Port

C　Port

D　Port

C　Port

D　Port

C　Port

10GbE

HDD×24in　each　Unit

10GbE

RVDB installed in Usuda 64m

RVDB System

ADS-1000(1GHz AD, 2bit)

DIO Unit2Gbps x 4 <-> 10GbE

DDB Unit(24 HDDS)

Correlation Support (KJJVC)

Mark5B

DIR-2000

K-5

Optical Fiber

RawVLBIData

Buffer

CorrelationSubsystem

DataArchive

Correlator Control & Operation

Mark5B

DIR-2000

K-5

Optical Fiber

RawVLBIData

Buffer

CorrelationSubsystem

DataArchive

Correlator Control & Operation

Pictured by Dr. Roh

8Gbps/antenna

16 I/O port120TB

Polarization Sprit Recording

Station 0

DIO

DDB

DIO

DIO

DDB

DDB

DIO

DDB

Playing back at a quadruple speed is possible.

Station 1Station 0

Station 1

Station 2

Station 3Station 2

Station 3

Station 4

Station 5Station 4

Station 5

Station 6

Station 7Station 6

Station 7

Station 0

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

1Gbps

1Gbps

2Gbps

512Mbpsx2

512Mbpsx2

RHCP LHCP

8-Gbps Processing

Conclusions

• A dual polarization receiver is important for coming VSOP-2 observations.

• An UWB receiver is important to achieve high sensitivity, especially in detecting cross polarized term.

• Wide band high speed data recorder is now available for the maximum 8-Gbps data rate.

• KJJVC in Seoul becomes soon ready for correlation of X-pol and UWB.