Receiver Systems Receiver Systems StatusStatus

20 January 2009 20 January 2009 Canberra Canberra

Mark Waterson, ANUMark Waterson, ANU

Subsystems:Subsystems:

Digital Receiver (RRI) Digital Receiver (RRI) ADFB - Analog to Digital & Filter Bank (2)ADFB - Analog to Digital & Filter Bank (2) AGFO – Aggregation & Fiber Optic (1) AGFO – Aggregation & Fiber Optic (1)

Node M&C Node M&C Arcom Single Board Computer (SBC) Arcom Single Board Computer (SBC) Diamond Systems GPIO cardDiamond Systems GPIO card

ATIM – Antenna Tile Interface ModuleATIM – Antenna Tile Interface ModuleATIF – Antenna Tile Interface Filter (8)ATIF – Antenna Tile Interface Filter (8)ASC – Analog Signal Conditioning (2)ASC – Analog Signal Conditioning (2)Chassis, Fans, & Power SuppliesChassis, Fans, & Power SuppliesThermal sensor interface cards (2) Thermal sensor interface cards (2)

Current Hardware Status*Current Hardware Status*

N1 - operational at MRON1 - operational at MRO

N4 – operational at MRON4 – operational at MRO

N2 – repaired, enroute to HaystackN2 – repaired, enroute to Haystack

N3 – operational at RRIN3 – operational at RRI

* issues with BF coms affect all* issues with BF coms affect all

* ATIF Walsh channels not fully tested* ATIF Walsh channels not fully tested

Current Issues: Current Issues:

Packaging & cooling Packaging & cooling

Clock systemClock system

Control Software (or lack thereof)Control Software (or lack thereof)

Beamformer interfaceBeamformer interface

Rev2 pcb modificationsRev2 pcb modifications

Digital Receiver development Digital Receiver development

Packaging & Cooling – PSI (Perth) Packaging & Cooling – PSI (Perth) Preliminary design in progress Preliminary design in progress

Clock system design/prototypeClock system design/prototype (CfA, ??) Preparing quotes for (CfA, ??) Preparing quotes for

design/constructdesign/construct

Rev2 boards Rev2 boards ASC gain/filter, connector (mfw) ASC gain/filter, connector (mfw) ATIM reconfigure (PSI/mfw/?)ATIM reconfigure (PSI/mfw/?) Backplane? (PSI/RRI)Backplane? (PSI/RRI)

SoftwareSoftware

““Core” control softwareCore” control software Basic “bit-flipping” routines existBasic “bit-flipping” routines exist ““Robust” framework defined but needs work Robust” framework defined but needs work Some DigiRec status features still need workSome DigiRec status features still need work

Interface between Central M&C and nodeInterface between Central M&C and node ICD defined, but not implemented completelyICD defined, but not implemented completely

Ed Morgan presently working (on Node2 )Ed Morgan presently working (on Node2 )

Beamformer Control InterfaceBeamformer Control Interface

Requirements:Requirements: CommunicationsCommunications Power control & distributionPower control & distribution (Lightning protection)(Lightning protection)

““ATIF/BTIF” boards – existing, need fixesATIF/BTIF” boards – existing, need fixes

““Data-over-Coax” – proto being builtData-over-Coax” – proto being built

ATIF/BTIF InterfaceATIF/BTIF Interface

Artwork faults appear to be solved in Artwork faults appear to be solved in current-generation boards – OKcurrent-generation boards – OK Filter components were incorrect on some Filter components were incorrect on some

boards, we boards, we thinkthink all fixed all fixed

48v DC current draw48v DC current draw issue with ATIM component identified, will issue with ATIM component identified, will

need mod to boardneed mod to board Fix/mod for Beamformers designedFix/mod for Beamformers designed

BF BF Long-cableLong-cable communication communication History:History:

Haystack never able to reliably drive long cables, even at 100HzHaystack never able to reliably drive long cables, even at 100HzANU never able to reliably read back temperature or checksumANU never able to reliably read back temperature or checksumANU has checked signal fidelity, appears clean (with correct parts) at ANU has checked signal fidelity, appears clean (with correct parts) at 100KHz & 200m100KHz & 200m

Work at site this week: Work at site this week: MIT-Haystack tester blew upMIT-Haystack tester blew upSome BFs tested with internal read-back boardSome BFs tested with internal read-back boardShort & long-cable waveforms recorded Short & long-cable waveforms recorded Readback data saved from SBC coms Readback data saved from SBC coms

>> no consistent, proper operation observed!>> no consistent, proper operation observed!Repeatedly observed BF not resetting on message start, conflicts with ICDRepeatedly observed BF not resetting on message start, conflicts with ICDErrors with both long and short cables Errors with both long and short cables Some ATIF dependencySome ATIF dependencyDID read back correct temperature & saw internal “ok” with SBC software DID read back correct temperature & saw internal “ok” with SBC software – ONCE…– ONCE…

Data and clock Data and clock waveformswaveforms

Long cables, Long cables, measured at BF end measured at BF end (geraldton)(geraldton)

ANU Bench tests:ANU Bench tests:

Clock & data waveformsClock & data waveforms

checksum & temperaturechecksum & temperature

Lab testing (ANU)Lab testing (ANU)

=> BF cpld seems to be missing data bits => BF cpld seems to be missing data bits (or clocks)(or clocks) Causes checksum & temperature errors seenCauses checksum & temperature errors seen Will cause tile mis-pointingWill cause tile mis-pointing Haystack to confirm, look at BF cpldHaystack to confirm, look at BF cpld

Walsh transition driveWalsh transition drive Waveforms confirm expectationWaveforms confirm expectation Impact of driver faultsImpact of driver faults

Walsh-sw transitionsWalsh-sw transitions

Walsh switchingWalsh switching

ATIF common-mode offsetsATIF common-mode offsets

MAX232 IC failures, usually seems to be drive MAX232 IC failures, usually seems to be drive side, (but hard to be sure)side, (but hard to be sure)

Mostly Receiver end, again not enough dataMostly Receiver end, again not enough data

……why???why??? Common-mode voltage difference between BF and Common-mode voltage difference between BF and

Receiver exceeds chip supply, turns on/burns out Receiver exceeds chip supply, turns on/burns out protection diodes protection diodes

Added ground conductors + internal tie reduced Added ground conductors + internal tie reduced problem (2problem (2ndnd Nov trip), may be solution Nov trip), may be solution

ATIF re-design? ATIF re-design?

Real problemReal problem – drive & receive circuits do – drive & receive circuits do notnot share share same “ground” reference, so same “ground” reference, so not possiblenot possible to to define/clamp voltagesdefine/clamp voltages

Solution: Solution: isolationisolation – optical or transformer – optical or transformer Opto-isolated 232 driversOpto-isolated 232 drivers

more-or-less same footprint as existing drivermore-or-less same footprint as existing driver

Well-understood drop-in circuit fixWell-understood drop-in circuit fix

ATIF/BTIF board revision requiredATIF/BTIF board revision required Transformer – Transformer –

already available in “manchester” version of existing design already available in “manchester” version of existing design

Requires mods to add encode/decode to data path (design done)Requires mods to add encode/decode to data path (design done) Capacitive – e.g. Eric/Roger’s serial data system?Capacitive – e.g. Eric/Roger’s serial data system?

BF Interface – now what? BF Interface – now what?

Soon (32T):Soon (32T): Complete & test “D-O-C” interfaceComplete & test “D-O-C” interface Revision of protocol to echo back BF data suggested: Revision of protocol to echo back BF data suggested:

Allows SBC to confirm pointing data bits Allows SBC to confirm pointing data bits Simple changes to both cpld code Simple changes to both cpld code Not compatible with D-O-C interface…Not compatible with D-O-C interface…

Settle ATIF (common-mode) and ATIM revisionsSettle ATIF (common-mode) and ATIM revisions Build & verify interface testers using field hardware Build & verify interface testers using field hardware

(SBC, ATIM, ATIF) so everybody uses same platform (SBC, ATIM, ATIF) so everybody uses same platform to testto test

Haystack visit to resolve? Haystack visit to resolve? Decision dates?Decision dates?

ASC High-pass filterASC High-pass filter

Existing commercial highpass filter causes Existing commercial highpass filter causes aliasingaliasingCustom design needed to optimize MWA Custom design needed to optimize MWA performanceperformance~ not trivial – ~ not trivial – FFcc = 300MHz, <<3dB desired = 300MHz, <<3dB desired FFstopstop = 330MHz, >30dB++ attenuation req’d = 330MHz, >30dB++ attenuation req’d

-> Lark, Minicircuits, …? Possible vendors-> Lark, Minicircuits, …? Possible vendors footprint change impacts board layoutfootprint change impacts board layout

LFCN-225 filter plotLFCN-225 filter plot

LFCN-225 filter dataLFCN-225 filter data

Receiver Development – Now Receiver Development – Now What? What?

Complete software – science can’t be Complete software – science can’t be done nowdone nowRevise hardware – Revise hardware – BFcoms DNWBFcoms DNW Production revisions – Production revisions –

ASC, ATIM, BF interface changesASC, ATIM, BF interface changes Field package design Field package design fiber data/clocks, thermal system, etc needed fiber data/clocks, thermal system, etc needed

to get to CDR to get to CDR

Decisions, decisions…Decisions, decisions…

Cooling system capacityCooling system capacity trade cheaper cooling solution (=>loss of trade cheaper cooling solution (=>loss of

high-temperature ops time) for more tiles? high-temperature ops time) for more tiles?

Assembly & test effortAssembly & test effort Trade servicability (design effort/$) for test Trade servicability (design effort/$) for test

ease/ modularityease/ modularity

ReliabilityReliability Interfaces, operating temperature, etc vs cost Interfaces, operating temperature, etc vs cost

& complexity& complexity

Existing ATIF problems vs. Existing ATIF problems vs. lightning…lightning…

Return path to case (faraday cage) for Return path to case (faraday cage) for transient protection should have been transient protection should have been through standoffs at ATIF board corners - through standoffs at ATIF board corners - BUT – boards mounted on connector only!BUT – boards mounted on connector only!

Cable shield not connected to connector Cable shield not connected to connector body -> no faraday shielding…body -> no faraday shielding…