VOICE PROCESSING GROUND RULES.

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

direct submultiple of 8000. By chance, the port rate is

3-55. The preceding paragraphs have identified and

also a direct submultiple of the 6-kbps (600N family)

discussed the major sources of multiplexer set

input to channel 3. A total of 19 ports (including

input/output inefficiency, and have provided examples of

overhead) is used in the configuration, and with a 2-kbps

how the inefficiency can be confined. Attention to

Rp, the Ro is 38 kbps (2 kbps x 19 = 38 kbps). Overall

efficiency, and the selection of configurations to enhance

efficiency is expressed as:

it, is of importance only when the individual multiplexer

set user is not otherwise restricted by superseding

(8 x 2) + 6 + 13.8

system configuration dictates.

x 100 = 94.21

percent.

3-56. VOICE PROCESSING GROUND RULES.

3-57. In the processing of voice channel data, a port rate

3-54. The example depicted in configuration B of figure

(Rp) of 19.2 kbps or greater is preferred. In such cases,

3-10 processes the same inputs as those discussed

the voice input is processed by using a single port (K =

above, but uses a port rate that is a submultiple of the C

x 75 x 2n family. This port rate (1.725 kbps) requires that

1). However, there are certain situations where the use

the port strapping assignments of the previous example

of lower port rates and/or port strapping arrangements

be modified to ensure that the product of port rate and

may be desired. The ground rules applicable to the

port quantity for each channel is equal to or greater than

processing of voice inputs with port rates lower than 19.2

the applied channel input rate. Differences between this

kbps, or port strapping (K > 2), are as follows:

product and the input channel rate for channels 1, 2, and

3 are adjusted internal to the multiplexer set by means of

a. For port rates of 19.2 kbps or greater, improved voice

coarse rate conversion. In this example, the total port

transmission quality may be obtained by using two ports

count, including overhead, is 23. The output rate is

(K = 2), provided that the first (active) port assigned to

1.725 kbps x 23 = 39.675 kbps, and overall input/output

the voice channel is an even number and the total

efficiency is expressed as:

number of ports used within the multiplexer set, including

overhead, is an even number (N + 1 = 16, 18, 20).

(8 x 2) + 6 + 13.8

39.675

x 100 = 90.23

b. For port rates between 9.6 and 19.2 kbps, two ports

percent.

should be used (K = 2), provided the total multiplexer

used port count (N + 1) is an even number (N + 1 = 16,

The efficiency is 3.98 percent lower than that shown in

18, 20). If N + 1 is an odd number, a channel sampling

configuration A of figure 3-10, and shows the effects that

rate (KRp) of 38.4 kbps or greater should be used.

result when a selected port rate is not related to the more

predominant of mixed input rate families. It should also

c. For port rates less than 9.6 kbps, acceptable voice

be noted that the decreased efficiency is experienced

transmission quality may be obtained, provided that a

with a configuration that uses a greater total number of

port strapping arrangement yielding a channel sampling

ports (23 versus 19) and a lower port rate. As discussed

rate (KRp) of 38.4 kbps or greater is used.

in paragraph 3-49, and without a mixture of input rate

families, an increased port count and lowered port rate

tend to increase efficiency.

3-27