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Telos Zephyr Xstream Two-Way Radio User Manual

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USER’S MANUAL

Section 6: AUDIO CODING REFERENCE 130

Mono vs. MONO128 vs. Stereo vs. J-Stereo in Layer-2

Withonetransmissionpath,

• L2Mono64providesmonocapability.

• TheL2HALF64Xmtmodeallowsoperationat24kHzwhenthissamplerate

isdesired,primarilywhencommunicatingwith“singleline”capableLayer‐2

codecs.

Withtwotransmissionpaths,

• L2MONO128providesthebestLayerIIqualitybycombini

ngboth

transmissionpathstoachieveahigherbitrate.Thismoderequires2data

paths.

• L2STEREOmodeissimplytwosimultaneousmonochannels.

• L2J‐STEREOmodeusesthe“intensitycoding”methodinordertoprovide

maximumqualityforstereoprogrammaterialandcompensatesforany

delaybe

tweenthetwotransmissionpaths.

SamplingRate

Thisoptionsetsthesamplerateforthetransmittedandreceivedcodedaudio.Input/outputis

(usually)independentofthetransmissionbitrateandissetintheAES/EBUoptionsinthe

AUDIOmenus.

TheZephyrXstreammaybeoperatedateither48kH

zor32kHzsamplerate.48kHzoffers

lowerdelayandincertainmodes20kHzaudiobandwidth.However,the32kHzrateis

generallypreferredforbroadcastapplicationsbecausenobitsarewastedonfrequenciesabove

15kHz–whicharenottransmittedinanalogbroadcastservices,anyway.

DecoderLimit

ations

• Ifyourapplicationrequirestheabilityforthetwochannelstocomeandgo

independently,suchaswhentheyarefromindependentsites,youmustuse

L3Dual/MonoorG.722.Thesearetheonlymodesthatsupportfully

independentoperation.

Z

ZEPHYR CLASSIC VS XSTREAM COMPARISON!

Zephyr's L3 Stereo receive mode, used to receive two, independent, mono signals, requires that

both channels be connected and operating in order for the decoder to function. Until both

channels are present, the decoder will not output anything, even if the Xmt mode at the other

end is not stereo. Any data dropouts could cause interruption of both audio channels.

Zephyr Xstream's L3 Dual/mono decoder allows for completely independent reception.

Therefore, it can accommodate incoming L3 mono from two sites simultaneously without

compromise.

Of course both Zephyr Classic and Zephyr Xstream can transmit L3 mono audio to two sites.

• Atypicalapplicationwhichworksperfectlywiththesemodesistheone

usedfordual‐languagesportsbroadcasts,withseparatestudiosites.Thisis

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