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2-12
T-Enc (Transition-Encoded)
T ran sitio n -E n co d in g m ay b e u sed w ith an y ty p e o f d ata. W h en th is circu it ty p e is selected , th e D ata II
C ha nn el m o d u le en co d es each b it tran sitio n in th e d ata stream u sin g a th ree-bit co d e. T h e tran sitio n -
en co d in g is p erfo rm ed acco rd in g to th e sp ecificatio n s o f C C IT T R .1 1 1 . T h e co d e p recisely id en tifies
th e o ccu rren ce o f each tran sitio n relativ e to a M E G A M U X P L U S tim in g sig n al. A ch an n el m o d u le can
th en reco n stru ct th e d ata u sin g th e co d e. H o w ev er, th e am o u nt o f ag g reg ate b an d w id th req u ired to tran s-
m it the co d e is fo u r tim e s th e b au d rate o f th e ch an n el. F o r ex am ple, if y o u co n fig u re a tran sitio n -en -
co d ed ch an n el w ith a b au d rate o f 9 6 0 0 b p s, 3 8 .4 k H z o f ag g reg ate b an d w id th is req u ired to su p p o rt th at
ch an n el. If y o u select th e b au d rate for a tran sitio n -en co d ed ch an nel, y o u w ill se e th at R E M A IN IN G
B A N D W ID T H fig u re is red u ced b y fo u r tim es th e am o u n t of th e selected b au d rate.
CVSD
CVSD is selected when the Voice II/CVSD Channel module is used for any voice channel; the
Voice II/CVSD Channel module must be in the slot associated with the selected channel number.
A data rate may be selected for a CVSD voice channel. The output level of a voice channel also
may be set as a channel parameter.
PCM (Pulse-Coded Modulation)
PCM is selected when the PCM or UVC/PCM Voice Channel module is used; the PCM Voice
Channel module must be in the slot associated with the channel number. A PCM voice channel op-
erates at a fixed data rate of 64 kHz (66 kHz of aggregate bandwidth are consumed by a PCM voice
channel. The extra 2 kHz of bandwidth are used for overhead and synchronization bits; when a
PCM channel is configured, the REMAINING BANDWIDTH figure is reduced by 66 kHz). The
output level of a PCM channel may be set as a channel parameter.
ADPCM (Adaptive Differential Pulse-Coded Modulation)
ADPCM is selected when the ADPCM Voice Channel module is used; the ADPCM Voice Channel
module must be in the slot associated with the channel number. The ADPCM voice channel oper-
ates at a fixed data rate of 32 kHz (34 kHz of aggregate bandwidth are consumed by an ADPCM
voice channel. The extra 2 kHz of bandwidth are used for overhead and synchronization bits; when
an ADPCM channel is configured, the R E MA I N I N G BANDWIDTH figure is reduced by 34
kHz). The output level of an ADPCM channel may be set as a channel parameter.
ASP (Advanced Speech Processing)
W h en A S P is ch o sen as th e circu it ty p e, either fix ed o r v ariab le rate A S P m ay b e selected , d ep en d ing
u p o n the v ersio n o f th e A S P C A R D in stalled in th e ch an n el slo t an d th e A U T O F R A M E m o d u le u sed .
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In software version X.10, an error is displayed when an attempt is made to configure an ASP chan-
nel card for a data rate it does not support. The current card supports four ASP data rates. Earlier
versions of the ASP channel card supported only one rate, 16K.
ASP Channel Card, GDC P/N 036M259-001 comprises ASP Base Card (036P255-002) with ASP
Piggyback Card (036P259-001) installed.
ASP Channel Card, GDC P/N 036M259-002 comprises ASP Base Card {036P255-002) with ASP
Piggyback Card (036P259-002) installed.
036R660-000, Issue 10
With the Voice II/ASP channel card installed (GDC P/N 036M259-001) in conjunction
with AUTO FRAME Plus module (GDC P/N 036P248-022/-023), only fixed rate ASP
at 16 kbps may be selected.
With the Voice II/ASP variable rate channel card installed (GDC P/N 036M259-002)
in conjunction with Universal AUTO FRAME module (GDC P/N 036P248-026),
variable ASP rates of 10 kbps, 11 kbps, 12 kbps and 16 kbps may be selected.
System Overview
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