Sage 930i, Руководство по эксплуатации, Страница: 37 / 236

© Sage Instruments 2000
9100-2930-02 01/31/00
Section III Front Panel Operation
Front Panel
Operation
3-18
If you are in 2W with a standard impedance selected, a display similar to the following appears:
No 2W RETURN LOSS AVAILABLE IN: 2W 600
If you are in 2W with a complex impedance selected, a display similar to the following appears.
If you are in 4W, a display similar to the following appears:
+0dB SRL LO ECHO +0 THL 4W 135
K1 K2 K3 K4
Entering the Return Loss function automatically sets the metallic trunk type to
TERM
. Check or change
the
TERM/BRIDGE
setting under the Trunk Type function key. (Refer to Section 3-7.1 .)
4. Press K1 to cycle between Echo Return Loss (
ERL
), Singing Return Loss Low (
SRL-LO
),
Singing Return Loss High (
SRL-HI
), and Structural Return Loss measurements. If you are
in 2W with a complex impedance selected,
TR TERM
and
AC SHORT 2W
are also available.
If you are in 2W, the
TR TERM
display reads:
TR TERM AC SHORT 2W
K1 K2 K3 K4
Pressing K3 allows you to cycle the termination between
AC SHORT 2W, 600+2uF 2W,
900+2uF 2W,
and
AC OPEN 2W
.
5. When measuring structural return loss, use the numeric keypad to enter the frequency of
interest.
• A valid tone is between 20 and 5000 Hz. The reading you get will not be valid unless echo
suppressors/cancellers are disabled; these may be present on long distance circuits.
6. Press K2 to toggle the echo canceller on and off.
7. Press the Return Loss function key to send the selected return loss signal, and receive and
display measurements.
3-2.3.1 Transhybrid Loss Measurements
The amount of loss across a hybrid which may be on a 4W circuit is used as a correction factor to the
return loss measurement. The loss may be known from previous measurements (in which case it can
simply be entered), or it may be measured by the 930i. In either case, the 930i will use this value to
correct its return loss readings. Pressing K3 allows you to measure and enter the
THL
(transhybrid loss)
correction.
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