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T.O. 31W2-2GSC24-2
TM 11-5805-688-14-1
NAVELEX 0967-LP-545-3010
five channels. Similarly, the value 3 is entered in the
3-45.
SUPPLEMENTAL
CONFIGURATION
PORTS (K) block for each channel. This completes
CONSIDERATIONS.
preparation of sheet 3 of the configuration worksheets
for the example shown in figure 3-4.
3-46. The preceding discussions relative to configuration
of the multiplexer set have considered its application to
3-43. DEMULTIPLEXER COMMON ELECTRONICS.
be within an overall communications system. Because
all elements of such a system must operate in a fully
3-44. Sheet 4 of the configuration worksheets (figure 3-
compatible manner, key factors such as output rate (Ro),
8) is prepared to enable setup of the demultiplexer
port rate (Rp), and port strapping assignments for a
common electronics section.
As shown in the
given multiplexer are fixed by overall system
configuration example in figure 3-4, the demultiplexer
requirements and are not subject to selection by the
input rate (Ro) is 1.536 Mbps; the value 1536000 is
individual multiplexer set user.
In such system
therefore entered in the INPUT RATE (Ro) BPS block.
applications, the configuration of a selected multiplexer
Assuming no phase reversals in the transmission link
set may be less than optimum in terms of input/output
from the far-end multiplexer, the DATA N and TIMING
efficiency, while overall system efficiency is in fact
N blocks are each marked with an X, indicating
optimized. Efficiency here is defined as the proper
normal. Since the 1.536-Mbps input is assumed for this
processing of all applied channel inputs while
example to come from a 75-ohm driver, an X is entered
maintaining the lowest possible output rate (Ro). There
in the INTFC 75 block. A link error rate environment of
are undoubtedly some applications, however, in which
one error per hundred bits (1/100) is considered
one or more factors of a multiplexer set's configuration
acceptable for this example; however, it is desired to
are left to user selection. In these situations, the user
indicate by an alarm when the error rate exceeds this
should strive to maximize overall input/output efficiency
value, and therefore an X is entered in the ERROR
while continuing to properly process all applied channel
RATE THRESHOLD 10-2 block. Port rate and port
inputs.
assignment entries are made, based on the example in
3-47. The user must consider two primary sources of
PORT RATE (Rp) BPS block, and the number 15 is
inefficiency when configuring the multiplexer set. The
entered in the PORTS IN USE (N) block. PORT A
first source of multiplexer set inefficiency relates to the
blocks 1, 4, 7, 10, and 13 are each marked with an X,
fact that regardless of configuration, one port is always
indicating active, and PORT S blocks 2, 3, 5, 6, 8, 9, 11,
used for overhead servicing. Since this port occurs at
12, 14, and 15 are each marked with an X, indicating
the same port rate (Rp) as all other ports, its contribution
strapped.
This completes preparation of the four
to inefficiency can be minimized by selection of the
configuration worksheets for the multiplexer set
lowest possible port rate consistent with proper
configuration shown in figures 3-5 through 3-8.
processing of the applied channel inputs. With a fixed
set of input rates to be processed, reductions in port rate
will necessarily require an increase in the
3-22
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