Murraypro Test Chest Quick start guide

Test Chest: Manual
1
Murraypro
Test Chest
+
EYE~POD
Operational Manual
Issue: 1V0

Test Chest: Manual
2
Test Chest
Manual 1V0
Congratulations onthe purchase of your Murraypro Test Chest
We are certain you willfind this tobeanextremelyquick to use, and
powerful diagnostic Tool. It will become atruly indispensable iteminyour dailywork
on the Bench, or whilst awayelsewhere investigatingproblemsunder batterypower.
Test Chest is an impressive Product,so let’sspend a fewmomentstogether
gettingto knowit, and exploringit’s features. In fact of course,most ofthemajor
features areimmediatelyobvious as theyare menu selected, but other rather more
subtle features maybea keypress or two away. Users who wish to get the most out
ofthe Test Chest arerecommended tofamiliarise themselves with the contents of
this Manual, and theUnit itself,before attemptingserious operational use of the
instrument inthe Field.We offer a short demoVideoshowingmany features:-
http://www.murraypro.com/testchest3g.htm
Introduction:
Test Chest is controlled bymeans ofatouch sensitive LCD panel and onlya
gentle touchingaction will be required to achieve the desired action.The LCD's
surface must NEVER be activated bya stylus such as a capped ball-pen, or,worse
still, a hardpoint suchas anuncapped pen ora screwdriver! Such activityis highly
likelyto cause scratch-damage tothe LCD's front panel;physical damage of this sort
is specificallyexcluded fromwarrantycover, and LCD replacements due to this
cause will be chargeable.
Ensure that the ‘Battery Off/Norm’ switch, situatedonthe leftend panel,
is in the‘Norm’ position, and 'Power up' is initiated byjust lightlytapping
the LCD panel anywhere, with the flesh of a finger. Next, ‘confirm’ this
'power-up?' command with a light tap on theSwitch Icon itselfwithin 4
seconds. Major functions arethen selectedand initiated bytapping the required
menufunctionfromthe'HomeMenu'page, which is presented immediatelyafter the
Test Chest power-up confirmation.Ina number ofinstances, Test Signal Generation
and the Wave-Formdisplay mode, for example, selection of the required output Test
Signal or WFM displaymode, will require a subsequent selectionprocess, via a sub-
menu. This direct switchingprocess is highlyintuitive, and extremely quick to
implement. There is no place on Test Chest for assignable 'Hot Keys' or anythingof
that nature. Often useofsuch key functions are verydifficultto track, as the required
'next' function's position changes as eachnew menu page is presented!
Users shouldbeaware thatsome Menu options, although subtle, will
substantiallyalter themode of operation. As maybe appreciatedfrom
the Test Chest’s “Video Generation” flowchart, selecting'Clapper
Board' for example, will bypass most other Video selections; whilst
selecting'OUT~LOOP'bypasses the local TSG, forcingthe output to be
a reclocked & equalised ‘LOOP’ ofthe input signal..... naturally, this can
onlyoccur if a signal isactually present at the input!

Test Chest: Manual
3
Selection of one of these powerful modes, whilst quite normal, could have a
high nuisance value' ifunintentional, andso the TC will helpfullyflagup such an
activation with a cautionaryyellowcoloured icon, or legend.
The cluster of4 BNCs on the right sideofthe front panel carryVideoinput
and outputs. Unbalanced AES and External sync is input on BNC2,whilst the TDR
cable-testalso shares this Port.
Balanced stereo audio input andoutput, together with the balanced AES OP,
are carried bythe D-25F connector on the left panel which coupleswith the
“Audio~POD” breakout adapter. The 3.5mmHeadphone Jackis locatedheretoo.
Test Chest: Front.
Power considerations.
Test Chest is powered when portable, from an internal 3000mAH 7V2 Lithium
Polymer batterypack. We have achieved nearly5 hours endurancewith a freshly
charged batteryin tests, so realisticallyUsers could anticipate in excess ofthree
hours operation.Power drain will be dependent to someextent upon LCD back light

Test Chest: Manual
4
brightness, the mode used, andthe Clock rate ofthe TV Standard.
Test Chest is unusualin that it has two quite distinct modes of operation, and
theseare totallydifferent, and separate, fromanybatterychargingconsiderations:-
a) In Which-Wire? mode, theunitwill detect an inputsignal on BNC1, and
power up automatically, displayingthe signal as soon asit is detected. NO action
beingrequired fromthe User, other to plugthe unknown sourceintoBNC1.
In “W-W?” mode, TC will automaticallypower down a momentor two after the
input signal is removedfromBNC1. 'Touching' the LCD panel will end the “ W-W?”
mode, andmanual 'power down' will be required to restore “W-W?” mode.
b) In the Generation and Measurementmodes,it will be necessaryto turn the
Unit ON manually. This is achieved gentlytappingtheLCD panel,and
CONFIRMING your 'power on' request bytappingthe Switch ICON presentedin the
bottom-right oftheLCD. In thesemodes, the Test Chest is 'powered down' bybriefly
tappingthe YELLOWswitch icon on the menuhomepage.
Test Chest provides essentially9functions,whicharedescribed
more fullylater,but theseareatpresent,perhaps,bestinitially
consideredunder3major separate function headings:-

Test Chest: Manual
5
1) Which-Wire?
Which-Wire? is an exceptionally powerful investigative tool in which Test
Chest emulates our earlier Murraypro 'Which-Wire?' Unit, and itis not even
necessaryto ‘manually’ power the Unit up for operation inthis mode.As soon as a
signal is appliedto the 'Which-Wire?' input Test Chest automaticallyawakens,
determines it’s signal format, automaticallyselectingtheoptimummanner to display
the detected signal, whether it be TV monitor, WFM,or asan audio histogram.
AdditionallyifaTV signal is detected,it identifiesthe source's TV Standard as 3G-
SDI, HD-SDI, SD-SDI, CVBS, together with it's Frame Rate,which is reported on a
Banner atthe top of the 16:9 LCD screen.
“W-W?” capabilityincludes 'Tri-Level' and
'Colour Black' Sync detection.Either sync signal is
displayed in the WFM's 'H Expand' mode.
“W-W?” capabilityon BNC1 includes the
detection ofUNBALANCED AES andSPDIF sources.
When present, the LCD displayautomatically selects
AES mode on the 'Audio Monitoring' page.
“W-W?” detection mode has beenextended to now
include High Definition Video Interfacesources which are applied
to the connector twixtBNC1 & 2.When detected, HDVIimages
@TV relatedscanrates will be displayed, sources onother
standards will be detected, butmaynot be coherentlypresented.
Users shouldconnecttheir 'mysteryIP signal' to the lowest BNC connector,
BNC1, designated“WW?” at the bottomright ofthe frontpanel. This connector
always terminates the inputwith 75W, so it is never necessaryto provide a separate
external termination. The fundamental feature of Which-Wire? Mode is that CVBS,
SDI and AES signals enter the Unit via the same connector.It is never necessaryto
double guess what signal maybe presenton a given cable, asthe Test Chest will
automaticallyswitch tothe appropriateDigital, Analogue, AES or Tri-level/Composite
sync mode, as required to correctlydisplaythe detected input which nowincludes
HDVI signals with TV related imageformats.
It is vital to appreciate that “Which-Wire?” mode can ONLY beinitiatedwith
the Test Chest un-powered, it cannot function when the Test Chest is already
powered upas it will already be in a ‘manually’ selected operating mode!
Followinga ‘manual’ power-up, the main menu is presentedfromwhich the
User selects ‘TV’, WFM’ or ‘Audio’ mode asrequired. ~ Let us assume ‘TV’ mode is
manuallyselected, so applyinga TVsignal tothe “W-W?” input will indeed display
an immediate picture, and infact this will be even faster thanfromquiescent, as the
Unit is alreadypowered, BUTit can’t identify Tri-level sync, or AES audio for
example, nor displaythese in anymeaningful manner in TV Monitor mode, as this
doesn’t offer any'WFM display' or AES measurement capability!

Test Chest: Manual
6
This powerful “Which-Wire?” auto-detection feature is an importantandvital
difference pioneered by Murraypro which completelyseparates Test Chest from
anyother product. Other testers will require Users to consecutively,and tediously,
offer an unknown signal to the separate SDI, CVBS and AES inputs in turn; if indeed
theyactuallypossess anyanaloguecapability at all!Consider for a moment, just how
does oneinvestigate and resolve a Station Reference Pulse problemwithout any
analoguecapability?
AES inputs in “Which-Wire?” mode.
Be aware that Test Chest’s highlyimpressivecapabilityofdetecting and
identifying“AES” signals fed in via BNC1, ONLY applies when the Unit is in
“Which-Wire?” mode, havingpowered itselfup automatically.
It most certainlydoes NOT applywhen theUnit hasbeen manuallypowered,
or if the “W-W?” mode has beenmanuallyover riddenwith a subsequent 'touch'
command. Under these powered conditions itis necessaryto applythe unbalanced
AES source directlyto BNC 2, the normal AES IP port, andwhich is labeledas such.
Under all 'powered' modes use of BNC 2 as the AES input port is mandatory.
AES signals manually presented to the “Video”port BNC1, will NOT be recognised.
2a) Test Signal Generation ~ Video
TSG.
The Test Chest contains a powerful,high quality,
10 bitTSG thatis suitable for testing TVequipment.
TheTV video format, categorized by‘Clock rate’ is selected first (1080 @ 3G, 1080

Test Chest: Manual
7
or 720@ 1.5G, or SD @ 270MB), followed by the required Frame rate (24, 25, 30,
50 or 60Hz), and on 60Hzrelated standards, subsequent sub-selection between
1.000 & 1.001 rates.On non-progressive only standards, interlacemaybe selected.
Support for Level B Dual Link at 3G is provided.
Menu selectionofthe differentTestsignals is easy
and intuitive, with the Generator providingparallel SDI
and CVBS outputs ofthe selected Test Signal on SD.
Tri-level syncgeneration.
The CVBS video output can ofcourse onlybevalid whilst the Test Chest is
generatingat 'Standard Definition' on 525 or 625 Standards, and is muted on HD.
However on all high definition standards BNC 3 will output Tri-level syncs, and this
changeover is completelyautomatic and transparent.
Tri-level syncs maybe loopedfromBNC 3 round to BNC 2,and then used as
an external reference for the Wave Form Monitor; this will particularlyuseful when
Test Chest is used to measure ‘Latency’ through digital equipment.
HDVI Signal generation.
Test Chest containstwo HDVI ports usingindustrystandard connectors
and suitablefor use with commerciallyavailable, or pre-installed HDMI cables; one
each for input andoutput and both are independentlyavailable whilstthe systemis
powered. A digital DVI OP is available via a proprietarypassive HDMI/DVI adapter.
These signals are primarilyintended for use inTelevision based
Engineeringapplications, rather than ‘Multi-Media’ entertainmentenvironments. So
although industrystandard connectors are used for convenience, the generation and
displaycapabilityis pitched towards confirmation offunction with SD andHD
Professional TV related displaystandards, and anon-exhaustive list ofthe generally
TV related Graphics standards that can be coherentlydisplayed is tabulated in the
Specification section.
HDVI signals generated by Test Chest maybe selected fromeithera
dedicated TSG or the LCD panel’s screen,and in either case theOP standardis
800x640.Either source maybe used as a convenient HDVI streamfor quickly
checkingconnectivityor systemfunction, and neither areintended for detailed
systemanalysis purposes although elementsof‘681 are supported.
Unlike some other Generators producingaPC/Graphics output, the
signals produced by Test Chest’s separate Graphics TSGdonot strayfrom ‘legal
values’.
If required, Test Chest can generatea separate SPDIF compatible audio
output too from the AES OP stream, via theAudio-POD’s integral BAL/UN matching
transformer.
Input looping ~ ‘Processing Amplifier’ mode.
SDI Equalisation and reclocking:
Usingthe Home Menu it is practical to “LOOP” external SDI signals
through the Unitand benefit fromthe internal equalisation and re-clocking
facility. Note that the menu flags this unusual settingwith yellow text.
CVBS looping:
Test Chest will also loop CVBS inputs. CVBS will be ac coupled to remove any

Test Chest: Manual
8
possible dc off–set on the input,and then clamped to remove dc changes due to
variations with Average Picture Level.
Text Ident:
A locallygeneratedidentification text stringmaybe inserted into the
output video,a particularlyuseful feature when identifyinglonglines. The
Character Generator's non-volatile memoryis pre-loaded with “TEST-
CHEST” when shipped; however it is veryeasilyreprogrammed to individual
requirementsbyusingthe Textmenu provided, an operationfamiliarto all mobile
phone Users.
ExternalvideoReference:
TC maybe Gen-locked (Slaved) to an external video Reference,this
allows the outputsignal to be ‘timed’ to a Vision Mixer, for example.
The external reference is applied as either a Composite video,Composite
or Tri-Level sync to BNC2. Selection betweenmodes is via menuicon. Beaware
that Mixed or Composite sync is onlyappropriate for SD, andthat HD standards
require Tri-level syncs.
Genlock operationis initiated via themain menu's “Gear” icon, which
leads to the Set-Up sub-menu page. TheTSG outputwill be maintained
locked within ½TVline ofthe Reference, enablingfullysynchronous
operation with digital equipment employing2H digital synchronisers.
Backlight:
Once the TSG mode has been set up, onemaywish to reduce the LCD's
back light drive to alower brightness. Using the 'Set Up' menuthebrilliance maybe
reduced, or switched to 'LCD DIM' modeto conserve batterypower.
Auto/Manual Power Management:
Under certain circumstances itmaybe desired to set the Test Chest to
generate a test signal for a prolonged period, perhaps whilst tests are
performed elsewhere.
If noicon 'activation' is detected for 10minutes, in ‘Auto off’ mode the Unit will
automaticallyshut down to conserve batterypower.
This time-out maybe defeatedbyselecting'Always ON' in the main menu. Be
aware however that when runningon batterypower, the Unit will continue tooperate
until the battery’s lowvoltage cutofflogic activates. No Li-Pobatterydistress will
occur, but the Unitwill not be capable offurther batterypowered operation until the
batteryis recharged.
Murraypro recommend thatthe battery isrecharged assoon as possible.
Test Chest maybe used, andwill continue to operate normallywhilst it's
batteryis beingrecharged. Charge completion is indicated bythe extinguishingof
the yellowLED twixt BNC 3 & 4.
It is not necessaryto remove the lowvoltage lead when chargingis
completed, and Test Chest maybe safelyrun for protractedperiods with the
‘charge/external power’ lead connected.

Test Chest: Manual
9
2b) Test Signal Generation~Audio
Test Chest generatesaudio in 3different formats simultaneously:-
1) Embedded Audio is inserted inGroup 1bydefault, but Group2, 3 or 4 maybe
manuallyselected for instead. Each channel 1~4 within the selected Group
maybe enabledor muted asrequired, with on-screen mappingto track and
displaythe current setup.
Audio modulation may be muted to ‘Digital Silence’. This does not affect the
digital house-keeping data, which is alwaysgenerated.
2) AES output stream. This is enabledbydefault andruns inparallel with and
uses the same source as Embedded Audio, via the'GenerateAudio'page.
Channels 1 or 2 maybe enabled, or mutedasrequired.
The Unit’s dual channel AES output is presented on the D-25F
connector asan110Wbalanced 48KHzAES encoded stream.This output
port is automaticallycoupledthrough to theAudio-POD when it is connected;
and itis accessed via the AES OP XLR3-M.
For Un-Balanced 75WAES operation, the balancedOP should befirst
routedto theBAL/UN (110W:75W)transformer on the Audio-POD,and then
extendedtotheloadfromthe POD's unbalanced AES 75 WBNC as usual.
3) Balanceddual channel analogue audio. Enable this mode which runs in
parallel with, and uses the same source as Embedded Audio, via the
'Generate Audio' pageand,as with the Embedded Audio, Channels 1 or 2
maybe enabled, or muted, as required.
The Unit's dual channel Analogueoutput is also presented on the D-
25F connector, and these lowimpedance balanced output ports arealso
convenientlycoupled through tothe Audio-POD, where it is accessed via the
AnalogueOP's dual XLR3-Ms.

Test Chest: Manual
10
AES Matchingwiththe Audio POD:
Generation & Monitoring
AES:Unbalanced IP @ 75 W.
Veryeasy, just couplethe coaxcable to BNC2Test Chest’s mainAES input.
AES:Balanced IN on XLR3-M @ 110W.
Couple IP cable XLR3-M to the POD’s
Transformer XLR3-F, and loop a short
BNC~BNC coaxroundto TC’s BNC2.
AES:Balanced OP@110RW.
Veryeasy! Just connect your XLR3-F cable to the POD’s AES OP.
AES:Unbalanced OP@ 75W.
Use an XLR~XLR ‘double ender’, couple
the POD’s XLR3-M AES OP back into
the POD’s transformer,andthen plug
your coaxcable into the POD’s 75W
BNC.
Output amplitude considerations:
The Embedded and AES digital audio bit-streamsmaybe operatedover a
muchgreater encodedamplitude range than that ofthe balanced analogue audio,
where practical considerations confines Test Chest’s limits to about +/-10dBU.
Do notconfusetheencoded audio amplitude data with the actual amplitude of
the AES bit streamwhich remains unaltered, at aroundRS422 levels; normally
around 3~4 V PP.
Digital outputs maybe adjusted in 1dB steps from0dBFS down to -80dBFS.
This lowoutputamplitude is useful for testingthe digital microphoneinputs ofa
Mixer realistically.Whilst theoverall envelopeofthe AES signal will remain atthe
standard RS422 level at all times, digital microphones usuallyemulate their
analoguepartners' lowOP level, generatingan AESoutput with a similar lowdigital
modulation amplitude.
Analogue amplitude:
The analogueaudio channel is aligned such that a level of“-18dBFS” will

Test Chest: Manual
11
produce a balancedanalogue OPof0.775VRMS = 0dBU, this is about 10dB below
the maximumOP. Users are reminded that the maximumbalanced analogueoutput,
which does embrace the normal +8dBU peak programme level, is headroom-limited
bythe internal batteryvoltage to about +10dBU.
Murraypro recommendusingan external 60dB XLR/XLR attenuator ifit is
desired to simulate 'Mic level' and similar lowlevel analogue signals.
Audio Sources:
1) The internal audiooscillator offers menuselected spot frequencies,and
amplitudes.
2) An External AES input maybe selected. Be aware that, although a 48KHz
source mayeasilybe monitoredandmetered, it will not bepractical to use it
as anEmbedded source, unless the 48KHzinputWord Clock is synchronous
with the output Video signal.
3) External Embedded Audio maybe selected that has been extracted fromthe
signal appliedto BNC1, the “Which-Wire?” input. Be aware that, as above,
unless the 48KHzinputWordClock is synchronous with the output Video
signal, it will not be possible to use itas an Embedded source.
4) TC3G offers a verypowerful Utilityin the “Audio Measurement” menu, which
indicateswhether an external AES input signal is synchronouswith a video
reference that is applied via the WW? Operation is describedunder the
following“AES/Video Lock Confirmation” passage.
5) A unique pulsed 'Tone PIP' identification can be added by TC3G toeach
audiochannel within a selected Group. This enablesdownstreammonitoring
points to correctly, andunambiguously, identifyeach channel individually.
600 W Audio loading:
Output loading: Test Chest follows current audio line drivingpractice, sending
froma current limited, balanced, lowimpedance source.
Test Chest follows Broadcast equipment’s input convention, bypresentinga
balanced load with a high impedance comfortablyin excess of10K W.
600Wloadsare very unusual with current audio practice, and thesignificant
loadingoftheXLR3-M balanced output bya 600W termination will cause areduction
in theoutput amplitudeofperhaps a couple of dB, bypotential divider action.
The outputs are current limited, and no damage will occur due to short circuits
or indeed 600Wloading.
3) A&V Monitoring
TV Monitor:
TC3G incorporates aTV Monitor function with 800x480 pixel resolution
which automaticallydisplays images in anysupported Format.

Test Chest: Manual
12
Mini-Histogram:
Tappingthe lower leftside of theTVmonitor displaywill toggle the burnt-
in HistogramON/OFF. See later text for more information.
Aspect Ratio:
TC3G defaults to a 16:9 aspect ratio, but 4:3 images maybe viewed in
their native format using the '16:9/4:3' menu option on the“Spanner”
Setup iconpagefor manual adjustmentofAspect Ratio.
This is Test Chest’sonlynon-automatic mode!
Measurement:
TheTV Wave-Form Monitor and Vectorscope functionaccepts SDI& CVBS
sources, automaticallyswitchingas required. Video signals
fromeither maybedisplayed as either standard video signals
with H or V Timebases; or in H Parademode,where the colour
information is sequentiallyswitched between either the YRGB, RGB, YUV channels,
or in Vector format.Toease channel identification, the Parade display sequentially
adopts the colour of the signal beinginstantaneouslypresented.
WFMdisplaymayre-positioned on the LCD by simplytouchingthe trace, and
dragging it to the desired position with a fingertip.
In the Composite videodisplaymode, theWFM's HF responseextends up to
well beyond 6MHz.
HDVI
Display:
Test Chest’s HDVI input port is designed toaccept ‘TVdisplay’(SD~>3G)
formats adheringto ‘681, and whilst the portwill accept signals on other graphics
standards, theymaynot be coherentlydisplayed.
Use of industry-standard connectors enablesPC Display, Graphic cabling,
and associated interfaces to be swiftlychecked out. This useful feature should be
regarded as an additional integral facility, significantlyexpanding"Test Chest's"
existingcapability, rather than as a substitute for a dedicatedGraphics Test Set.
WFM & Vectorscope:
HDVI waveformsmaybe examinedeither on the Vectorscopeor displayed as
a signal in WFMor Parade mode.
The Ychannel displayscalingadheres toBroadcastSMPTE standards, and
sources that do notconform with theseare easilyspotted.Excursions belowblack
level and above 100% are caused bycoding with ofout ofrange values, as the out
ofgamut signal generated bythis lowcost HDMI generator demonstrates well!

Test Chest: Manual
13
This HDVIinput signal contains out of Gamutvalues!
Touch-Shift:
Usingthe LCD's touch panel, waveformsmaybe 'dragged' in both the X& Y
planesto align the trace with the graticule,to facilitate measurements.
TheWFMdisplaymay, in SDI mode only, be
synchronised to an External Reference.This
Reference signal which maybe either Tri-Level or
Colour Black, is applied via BNC2. BNC2 hasa 75W
impedance and is also used for the dedicated AES
input andas the TDR port.
TheWFMVertical sweep displaymaybe
expanded toreveal further detail duringthe active frameperiod.
Swipingfullyacross the whole width ofthe LCD screen in onecontinuous
action will increase both position in theFrame/Field, and the rate ofshift. An on-
screen counter displays the delayin 'TVLines' between the WFM’s vertical trigger
point,and the start of the displayed period.
With PAL/NTSC CVBSsources, unlike theWFM, the Vectorscopedisplays
only'Active Line Time' chrominanceinformation, andthe colour Burst is therefore
suppressed.
When confirmingoptimumWhite or Black ‘Balance’ on aCamera etc, the
displaygain maybe increased,usingthe icon onthe Vectorscopemenu page.
“EYE” andJitter:
This feature is supported bytheTest Chest’s EYE~POD accessory, which
provides the EYE andJitter measurement capability, which is accessed via theWFM

Test Chest: Manual
14
menu. Eye monitoringand makingmeasurements do require this module, andare
not supportedunless this is present.
Instructions for theuseof EYE~POD arepresented in therear section ofthis
manual.
Audio Measurements:
The TC3G provides two independent type ofaudiolevel measurement,
“Histogram” and “Numeric”, and generallybothforms are available simultaneously.
The histogramdisplayis highlydynamic andprimarilyintendedfor use when
measuringprogrammeaudio amplitude,but is suitablefor steadystate tones too.
The numeric display, which appears onthe top 'banner' field, is heavily
damped, and is onlyintended for use with steady-state tones.
Usingthe Test Chest’s75WWW? input port, Audio Monitor mode provides
accurateaudio level monitoringofembeddedaudiosignals via the Audio menu.
Embedded audio levels for the selectedGroup are presentedin histogramformat, as
4 columns on theLCD screen, andit is immediatelypossible to unambiguously
differentiatebetween an AESreference level at -20FSand an EBU reference at -
18FS, whenusingeither measurement facility.
The histogramdisplayoffers menu selection between the quaisi-peak~semi-
logrithimic scalingof BBC PPM, Nordic, DIN & Digital scales or the more
transient VU Scaling +ballistics which offer additional sub-selectionfor operation
with different Reference levels.
The usual BBC PPM scale sensitivity(-18dBFS = PPM”4”) maybe preset via
the audiomenu so that either the ITU or SMPTE (-20dBFS) Operational Reference
levels are 'normalised' to read PPM = “4”, makingthe subsequent evaluation of
SMPTEprogrammeaudio level considerablyeasier.
The histogram's “Digital” scale has 1dB graticule gradations coveringlevels
from0dBFSdown to-29dBFS, with icon selection of additional switched gain blocks
of+30 and +60dB. This additional gain allows AES & Embedded level
measurements down to around -90dBFS.
In-vision Histogram:
TC3G provides a neatin-vision histogram feature which may
be displayed whilst in the 'TV Monitor' mode. Useful for
confirmation that audiois beingsatisfactorilyreceived,
especiallywhen outputfromtheloudspeakersis muted.
Accordingto thetype ofthesource, the histogramdisplaymay
be stereo or 4 channel.
This is a simplified display, bearinggraticule points at -18 and
-10dBFS(=0dBU & +8dBU analogue) and emulates the full scale histogramscaling
selectable via the Audio Monitoring menu. The burnt in mini-displayis enabled or
disabledbytappingthe lower leftregion of theTVmonitor's image where the
histogramwould be/is presented.
Audio Phase:
Test Chest includes Audio Phase error detection for each of
the Ch1/Ch2and Ch3/Ch4 pairs ofthe selected Group. With
embeddedaudio both channel pairs are presented; whilst with
balanced analogue input onlythe single stereo pair can bemonitored. Either
detector will instantly"RED"flaga phase inversion of one channel, with respect to

Test Chest: Manual
15
the other; and whilst the effect is instantlyrecognisable with steadystate test tones,
it could takea momentor two before an error is apparent on Programme Audio due
to the varied nature ofthe real-world signals encountered. On a normal Programme,
with correctlyphased stereo, one would anticipateonlyan occasional, and
momentary, "RED"flag; whilst in the presence ofa phase inverted channel, one
might anticipate a near continuous"RED"flag.
TC3G digitallycompares the amplitude of“M” & “S” channels derived from
each stereopair. Withtrue stereo (not necessarilytrue with ‘electronic’ music),
almostwithout exception the amplitude of the “S” channel will seldomexceedthat of
the “M” channel,and then onlyon peaks,except inthe presenceof a phaseerror.
“S > M” will, after integration, therefore be flagged as an error.
Prolonged illumination ofthe red“PHASE” flag will leave little doubt that a
serious audio phasingproblemexists, requiringimmediate remedial action.
AES Audio:
Usingthe Selector on the Audio Monitor sub-menu, a 48KHz
unbalanced AES streaminput on the 75 R BNC3, maybeselected for
monitoring.
Essentially, thesameoptions as for Embedded Audio are available.
BalancedAES IP:
Balanced AES sourcesshould be first routed, to the BAL/UN
(110W:75W) transformer on the Audio-POD, and then
extendedonwards, usinga short BNC~BNC cable to BNC 2,
in theusual way.
AES/Video: Lock Confirmation
Test Chest includes averyuseful Utilityto confirmthat the48KHz
Word Clock ofthe AESinputsignal on BNC2, is synchronous with the
chosen Video Reference signal, fed in this case via BNC 1.
Touse this feature, theAES INPUT modeshould first be selectedon
the 'Monitor Audio' sub-menu. The ReferenceVideo, with which synchronism is
beingchecked, is applied to the 'Which-Wire?' input via BNC1.
When synchronous, the ‘lock’ flagshould bea solid green. Shouldthese
signals be asynchronous, the "AESLOCK"flagon the audiomonitor page will
change stateto red and will pulse at the 'beat' frequency, referringto their difference
at 48KHz.
Flash rateof1Hzequates toa difference error ofapproximately20 parts per million.
Audio Monitoring
Loudspeakers:
Be aware that when monitoringAESor Embedded sources, overall system
gain is controlled bythe switched +30 and+60dB presetgain icons, with the
loudspeaker volume level beingcontrolled with the up/down icons on the main menu.

Test Chest: Manual
16
Usingthe Audio sub-menu the frontpanel loudspeaker mayselect between
‘Ch1 + Ch2’ or ‘Ch3+ Ch4’ pairs for each of the 4audio groups. Stereo audio for
each channel pair 1&2through to 15&16, maytherefore be monitored onthe
convenientlymounted front panel stereo speakers; or on Headphones when theyare
jacked into the side-panel mounted 3.5mmsocket.
When jacked, the headphones automaticallymute themodestlydimensioned
loudspeakers,andfurnish significantlyenhanced audio quality.
***************** !!! CAUTION!!! *****************
Headphone operation
Users are cautioned to operate the Test Chest's headphone port with
restricted volume levels. Always advance the volume froman initial lowsetting.
The headphoneoutputhas limited current drive and is voltage limited by
design, but Murraypro has no control over User's choice ofheadphone.
Some high efficiencytransducers, closelycoupled to the ears, maybe able to
produce pressure levels that are hazardous to hearing.
External Display
Sometimes it mayprove useful to be able toport the Test Chest's 800x480
displayon toanexternal PC type monitor. This is easilyachieved usingthe 19 pin
HDVI output port at thetop ofthe right side panel, active whenever Test Chest is
powered.
Low latency display
Test Chest’s image processinghas been designed to provide acceptable
qualityimages on the internal 800 x480 pixel LCD, and is asubtle balancebetween
conflicting‘interpolation’, ‘latency’ and batterydrain considerations. Our chosen
solutionshuns power hungryinterpolation techniques involvingmulti-frame storage
and digital multiplication, in favour ofdirect ratio-metric processing.This achieves an
impressive through-putwith a maximumLCD latencyofaround 1 field (with
interlacedsources).
This is a neat solution for abatterypowered Tester with a 5” panel, which
makesnoattempt to offer “Grade 1” images. A major improvement in both
processingspeed and power economyhave resulted in excellentbatteryendurance
too, and ALL this hasbeen tradedfor onlya modest increase in interpolation
artefacts.
You maywish to ensure thatthe Power Management option on themain
menu is set to“AlwaysON” rather than'AutoOff', or the Test Chest will
automaticallyde-power 10 minutes after your last keypress!

Test Chest: Manual
17
Additional functions are present within the Test Chest, and
these are discussed below:-
Audio Signal Tracer
The internal audioamplifier is alsooperationalin WFMmode, andmaybe
selected via this threestep operation:-
1) On the Home Menu,select the Input = “W-W?” option.
2) On the Home Menu,select the “Audio Monitor” option.
3) Tap the diagrammatic “switch” icon on thelower-left of the LCD screen until
“W-W?BNC” is declared at the end ofthe top banner text.
Note that although, normally Test Chest automaticallypre-routesthe
audioassociatedwith the selected video source to the audio monitor;
the “switch” icon onthe “Audio Monitor” page permitsmanual over-ride,
to give total flexibility.This might be particularlyuseful when comparing
an SDI embedded audio against it’s balanced analoguecounterpart.
When the audiomonitoringamplifier is switched to “W-W?” input(BNC 1),
this feature becomes areallyuseful tool for audio investigation andsignal tracing.
Audio volume level is controlledbythe Home Menu “up” and “down” selection.
Clapper Board
'Clapper Board' is a proprietaryTest Signal that is designed to show Audio/Video
delayinequalities that aTV signal mayhave incurred, usuallyduetoexternal Video
processing, and which has not been accompanied with thecomplementaryaudio
delay. It is not designed to correct an error, simplyto demonstrate that one is
present, and which requires remedial action.
“Simplicity” is the word, and all that is required at a remote MonitoringPoint is
a pictureMonitor with lowLatency, and a Loudspeaker.
The picture shows a diagrammatic, functionalrepresentation of theClapper
Board signal as generated,for feedingto a Remote Location.The 'Puck' is
represented bythe white dot which travels rhythmicallyacross the screen fromright
to left; and at 'time zero' a white flash is generated together with a briefpulse of
audiotone. The Clapper Bd's 'Puck' speedis calibrated so that each major graticule
division represents 100mSoftime.

Test Chest: Manual
18
Whilst 'Time zero', Flash and tonepulseare co-incidentwhen generated;
subsequent (particularly)video processingincurred duringprogress alongtheLink,
mayresult in a delayin-equalityexperienced bythe Audio andVideo components.
An error of several Frames ofdifferential delay is entirelypossible, with a disastrous
effecton“Lip Sync”, an effect thatwill be painfullyobvious to all downstream
Viewers.
At the Receive Point, the Observer simplyjudges precisely where the tone
blip actuallyoccurs, with respect tothe instantaneous positionofthe travelling'Puck'.
It mayhelp to estimatethe error more accurately, ifthe screen zone outside the
area of interest is simplymasked off temporarilywith boththe Listener's hands, to
leave a 'trackable slot' that is centred where the toneinterruption occurs.
LCD Aspect Ratio
Users maywish to optimise the Aspect Ratio ofthe internal LCD panel in
order todisplayHeritage 4:3 pictures correctly.
The Test Chest’s LCD aspect ratio is toggled usingtheAspect Ratio option
on the “Set Up” menu, accessed via the 'Spanner' icon. Note that this feature is only
operational when theLCD is displayinga TVPicture, thus ensuringthat the menu
pages are always completelyvisible.
Cable Fault Detection (TDR)
Test Chest offers Time Domain Reflectrometryutilityfor the
identification, and location, of cable problems.The TDR launchesa
fast pulse froma precision 75Wsource impedance, into the near end
ofthe problemnetwork which is connected to the TDR port, BNC 2.
Witha correctlyterminatedcable, all the launch energy will be absorbed by
the terminatingload at the far end of the cable; however, should thatload not
perfectlymatch the network’s 75Wimpedance, a percentage of the launch energy
will be reflected back fromthe far end ofthe cable, andis directlydependentupon
the magnitude ofthe error, verysimilar to a RADAR return.It is this reflected energy
which Test Chest detects and displays onthe LCD’s display.
TheTDR launches fast16 nS pulses, and longer cables will have higher
losses, and so absorb more energy, therebyproducinglower amplitude reflections.
You maywish to ponder the factthat with all cables, energy reflectedfromthe far
end ofanycable will have travelled twice thatdistance before beingdetected.
Users maychoose to obtain improved performance and so resolvesmaller
TDR artefacts byincreasingthe displaygain, but the noise floor is compromised.
The Xaxis (Time-Base) ofthe displayis calibratedin Metres for Belden 1694
(5~180M). An unterminated cable shows a positive reflection, whilst a short circuit
shows as a negative reflection,with distance to anomalyindicatedon the Xscale.

Test Chest: Manual
19
The velocityratio ofthis cable (0.82),is similar to that ofother qualitycoaxial
cables, andthe distances indicated maybe used, with onlya small nominal error, as
a direct guide with manyother cables types.
In a 75Wsystem Test Chest was veryeasilyable to differentiatebetween a
correctlyterminated system,and one which is:-
a) Opencircuit (unterminated).
b) Incorrectlyterminatedin 110W.
c) Incorrectlyterminatedin 50W.
d) Double terminated with 2 separate 75Wloads.
e) Correctlyterminated, but containingan unterminated “stub”.
Tests demonstrate thata stub only50mmlong, T-Piece'd in, 10M before the
end of110M ofcorrectly terminated Belden 1694 is clearlydetectable.
It is unlikelyhowever that, unlesssignificant, mechanical deformation due to
cable compression would be readilydetectable.
This annotated photoshows
Test Chest’s 16nS TDR
pulse probinga 100M high
qualitycoaxial cable and
revealingan obvious glitch.
This photo, taken followinga
Client demonstration, shows
that this glitch is due to the
presence of a 50WBNC
elbowimmediatelybefore
precision 75Wtermination.
Remember, all this reflected
pulse energy has actually
traversed 200M ofcable!
‘SDI Event’ logging
Test Chest incorporates an‘HD/SD-SDI’ Error loggingUtilitywhich is
accessedfromthe main menu, through the ‘Set Up’ menu (Gear icon).
After initiation throughthe ‘Start Log’ icon, 8 parameters arecontinuously
monitored for error codes which, when detected, are logged against the internal
RTC. The Logger has been designed to operate independentlyofexternal time
references, and it is NOT necessaryfor the inputvideo signal meta-streamto contain
VITCdata, however an option to select VITC timefor loggingis envisaged.
A runningcountofthe total number oferrors that has been detected in each
ofthe 8monitored ‘error’ fields is presented for information.
Logging:
Note that once initiated, theError Loggingcontinues in the background, even
ifan operation on another menu page is selected.

Test Chest: Manual
20
When Loggingis in progress Test Chest forces the power
timer into “Always ON”mode. Else, with “Auto Off”mode enabled
poweringdown occurs 10 minutes after the last icon-touch, and
this might just prove tobe veryannoying!
The ‘Auto Off’ default power setting is automaticallyre-instated when the
loggingactivityterminates.
Operation under battery power is time limited, andthe internal battery’s
endurancewill be determinedbyage, condition, stateofcharge, and the Clock
speed of input signal beingmonitored. Nominal figures for guidance below:-
SD-SDIHD-SDI 3G-SDI
Batterycurrent 720mA800mA900mA
Nominal endurance 4H3.75H3.3H
Mains powered operation is recommended for lengthy loggingoperations!
The non-volatile memorystores the first 100 logged events, with up to 230
occurrences ofeachtype counted,and when presentindication ofcounter overflow.
Error flags aregenerated when anyofthe conditionsbelowoccur:-
1 TimingReference Signals: SAV & EAV protocol error detected.
2 AncillaryData (various): CRC invalid
3a CRC-AP: Check Sumfailure for the SD only ‘Active Picture’ area.
3b CRC-Y: Luminance Check Sumerror HDonly.
4a CRC-FF: Check sumfailure for the SD only ‘Full Frame’ period
4b CRC-C: Chrominance Check sumfailure HD only.
5 Line: Declares that ‘encoded line number’ declaredin HANC is incorrect.
6 Lock: Confirms SDI receiver ‘unlocked’ in the presence of valid SDI source.
7 Illegal: Confirmation that value‘000’ or ‘FFF’ has beendetected.
8 Gamut: Y/C Colour SpaceLPF’dvalues exceed -1% or +103% systemlimit.