IVS-4th General Meeting, Concepción- Chile, Jan 2006 DBBC - A Flexible Platform for VLBI Data...

IVS-4th General Meeting, Concepción- Chile, Jan 2006

DBBC - A Flexible Platform for

VLBI Data Process

G. Tuccari, S. Buttaccio, G. Nicotra - Istituto di Radioastronomia CNR - Italy Y. Xiang - Shanghai Astronomical Observatory, CAS – ChinaM. Wunderlich - Max Planck Institute fuer Radioastronomie, Bonn - Germany

4th4th General Meeting International VLBI ServiceGeneral Meeting International VLBI ServiceJanuary 9-13, 2006January 9-13, 2006

Universidad de ConceptionUniversidad de Conception

NEXT GENERATION VLBI2010NEXT GENERATION VLBI2010


DBBC Project

• ‘DBBC’ is a project supported by the European VLBI Network for the development of a Digital Base Band Converter

• The main goal was to replace the existing terminal with a complete compact system to be used with any VSI compliant recorder or data transport

• Hardware programmability is the main feature in order to optimize the architecture to the needed performance having the possibility to arrange different architecture in the same hardware support

• The new development is compatible with the existing terminals and correlators


DBBC Project (cont.)

• The new backend is fully up-gradable and ready to process larger bandwidth with new generation correlators

• Upgrade or improvements is mostly only software

• Upgrade is also possible in hardware replacing compatible ‘pin-to-pin’ processing modules

• Data out as VSI interfaces


DBBC General Features

• 4 RF/IF Input from 16 in the range 0.001-2.200 GHz

• Four polarizations or bands available for a single group of 64 output data channel selection (support 2 VSI)

• 230,29 Hz frequency sampling clock

• Channel bandwidth ranging between 250KHz and 16 MHz (MK4)

• Channel bandwidth between 32 and 512 MHz (wide modes)

• Tuning step 1 Hz

• Multiple architecture using fully re-configurable FPGA Core Modules (Down-Converter, Equally Spaced Multichannel, etc.)

• Modular realization for cascaded stack processing


DBBC General Schematic

ADB 1

PC FS PC

230,29 MHz Synthesizer

H-Maser

2xVSI64 ch

CORE

HSI

HSO

PCIInterfaces

AGC/Filter

IFD1,2,3,4IFC1,2,3,4IFB1,2,3,4IFA1,2,3,4

ADB2 ADB 3 ADB 4 HSIR

HSOR

CORE

HSI

HSO

HSIR

HSOR

AGC/Filter

AGC/Filter

AGC/Filter

CORE

HSI

HSO

HSIR

HSOR

FILA

FILA

CCM CCMR CCM CCMR CCM CCMR

HSO

CCMAnalogMonitor


System Components

• ConditioningModule • FiLa board – First/Last (VSI int., DA monit,

Clock and Timing - 230,29 Hz Synthesizer, Communication, JTAG channel)

• ADBoard – Analog to digital conversion• CoreModule boards – processing unit• FPGAs Core Firmware Configurations• PowerDistributor• PC Board + PCI interfaces (commercial)• System Management Software, Field System

oriented


Schematic System Top View8U x 84 TE x 500 mm

ADB CoreModule

VSI

IF2 IF3 IF4

10 MHz

1 PPS

IF1

PC and

Interfaces

FiLa

FiLaVSI

Ethernet

D

I

S

KJTAGAdapter

Monitor

IF1

IF2 IF4

FiLa

ConditioningModule

min 1 – max 4ConditioningModule

FiLaVSI

PowerDistributor

IF3


ConditioningModuleConditioningModule

Pre-AD Conversion Signal Conditioning

Pre-AD Conversion Nyquist Band Definition

4 IFs input selection

Output Power Level Control

Total Power Measurement


FiLaFiLa BoardBoard

First and Last board in the stack

First: Communication Interface JTAG programming channel 1PPS synchronizer 229-30 Hz synthesizer

Last: 2 VSI Interfaces DA Converter


ADBoardADBoard

Analog to Digital Converter

Analog input: 0 - 2.2 GHz

Sampling clock: 230-29 Hz

Output Data: 2 x 8-bit @ 229-28 Hz DDR


CoreModuleCoreModule

Basic processing unit

Max Input Rate: 4 x 8.589 Gb/s

Max Output Rate: 8.192 Gb/s (64 ch @ 128 MHz)

Digital Down Converter: 1 CoreModule = 1 BBC

Programmable architecture

Equally Spaced Multichannel: 1 CoreModule = 64 channels


Core Module Board

• HIS/HSIR Cascade-able Input Bus 4x2x8-bit @ 229 MHz DDR

• HSO Shared Output bus 2x32bit @32, 64, 128MHz

• CCM Control / Configuration bus 32bit

• CCM Monitor bus to DA converter 12 bit @500 MHz

• 1 FPGA VirII-1152pin, 3000 (4000 - 6000 – 8000 compatible)

• Stack cascade method to join up to 16 boards


DBBCDBBC4 ADBoard + 8 CoreModule Stack4 ADBoard + 8 CoreModule Stack


DDigital igital BBase ase BBand and CConverteronverter


Digital Base Band ConverterDigital Base Band Converter


PC Board: System Management Software

• Standard commercial PC board including HD

• Configuration files for each FPGA stored on HD

• Software interface for FPGA configuration

• Software interface for servicing FPGAs (I/O registers access)

• Software interface for AD level control

• Field System – like commands in standalone and remote (ethernet)


Minimal Architecture

With fixed configuration and external RF control and clock generation:

• 1 ADBoard • 1 CoreModule (multichannel configuration,

or any other)• 1 FiLa board (VSI interface, DA converter,

etc)• Components cost < 3.5 K€


Maximum Architecture

With fixed configuration and external RF control and clock generation:

• 4 Conditioning Modules• 1 FiLa board• 4 ADBoard • 16 CoreModule • 1 FiLa board• PC and PCI interfaces


DBBC System in January 1st 2006• Ready for testing in radiotelescopes• Next TOG in Westerbork in March demonstration

on field• Program with observations/optimization• Update program for improving performance:

- FPGA Virtex4 device for double processing clockand price reduction

- Faster AD sampler for input bandwidth increasing- AD sampler placed inside the receiver and sampled data

sent through an optical fiber- RFI Mitigation Board: the first CoreModule (same

hardware) acts as RFI processor in transfer the pure sampled data with proper configuration.


First Results with the mDBBC prototype(collaboration Italy-China)

• First digital x analog fringes detected on Nov 23, 2004 in the Seshan-Urumuqi baseline

• First digital x digital fringes detected on Feb 2, 2005

in the Noto-Seshan baseline


Conclusions

• The DBBC system is an high flexible instrument because is able to produce independent tunable channels for a full compatibility with the existing acquisition system and correlators. One CoreModule board is replacing a BBC module.

• Combination of up to 4/16 IFs in a single module is possible.

• The DBBC system is able to handle also equi-spaced multichannel configuration for producing contiguous not tunable channels. One CoreModule board is able to produce multiple channels.

• More solutions are possible within the same system with software selection


The DBBC is here:

Please ask if you need to have a look inside!

IVS-4th General Meeting, Concepción- Chile, Jan 2006 DBBC - A Flexible Platform for VLBI Data...

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