Sage 930i, Руководство по эксплуатации

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5-119 © Sage Instruments 2000
9100-2930-02 01/31/00
Sage Instruments 930i Communications Test Set
5-59 OPTION MENU #:59 ECHO CANCELLER DISABLE
OPTION MENU #:59, ECHO CANCELLER DISABLE, is a standard feature that enables you to disable
the echo canceller.
G.165 echo cancellers are used to suppress unwanted echoes from the transmitted signal on a circuit.
These are the most common type of echo canceller, and react to phase reversal.
Some circuits may also have older G.164 echo cancellers (echo suppressors), which do not react
to phase reversal. These echo suppressors turn off transmission in the reverse direction while a person
is talking in order to suppress echoes. Such suppression, however, impedes fully duplexed data, such
as the bidirectional flow of data between two modems and bidirectional BERT tests.
The echo canceller disabler on the 930i sends a tone (2100Hz with phase reversal) for 1500ms, which
is ITU compliant with G.165 echo cancellers. This tone is designed to disable all G.165 echo
cancellers, although it also disables all G.164 echo cancellers on a circuit.
To disable the echo canceller:
1. Press the Option Menu function key.
2. Use the Up/Down Arrow keys to scroll through the option menus, OR select 59 using the
numeric keypad and then press the Option Menu function key. The display reads:
OPTION MENU #: 59 ECHO CANCELLER DISABLE
K1 K2 K3 K4
3. Press ENT or any soft key (K1-K4) to activate your selection. The display reads:
MODIFY: LEVEL FREQ TIMING
K1 K2 K3 K4
4. Press K1 under
LEVEL
. The display reads:
LEVEL: -12.0 dBSTLP DEFAULT EXIT
K1 K2 K3 K4
5. Use the numeric keypad to enter a new level, and then press K4 to exit to the
MODIFY
display.
• A valid level is between
-99.9 dBSTLP
and
99.9 dBSTLP
or
-99.9 dBm
and
99.9 dBm
.
The default is
-12.0 dBSTLP.
Press K2 to toggle between
dBSTLP
and
dBm.
Option Menu #:
59
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