3-51
Performance Tests
External Mux/Demux
DS-1 Positive Pulse
2 Disconnect the UUT 100Ω DROP port from the Test Set and connect
to the Oscilloscope via the HP 15508B Balanced to unbalanced
Converter. Terminate in 75Ω at the Oscilloscope input.
3 Select CHAN 1 on the Oscilloscope and set to 1MΩ input impedance.
Load the Telecom Mask
4 On the Oscilloscope, use the following key sequence to select and load
the required Telecom Mask:
a/ SHIFT (Blue Key) APPLICATION.
b/ softkey.
c/ Use ENTRY/MEASURE control to select DS1_NEW in the
highlighted MSK FILES window.
d/ softkey.
Compare Pulse with Mask
5 On the Oscilloscope, use the following key sequence to compare the
pulse with the mask:
a/ RECALL 8, (Ensure CH1 Impedance is reset to 1MΩ. Select
TRIGGER, SETUP and set softkey to ).
b/ DEFINE MEAS
c/ softkey
d/ softkey
e/ softkey
f/ softkey
g/ RUN
NOTE Using the balanced to unbalanced converter reduces the pulse amplitude
by a factor of 1.266. This will cause the comparison with the mask to fail.
To overcome this select CHAN 1 ON and reduce the Volts/Division setting
(highlightedonthe softkeydisplay).ReducedVolts/Division= highlighted
value/1.266. The new value can be entered using the keypad
6 The Oscilloscope will compare the positive pulse with the mask limits.
A PASS message should appear on the Oscilloscope.
NOTE It may be necessary to visibly fit the waveform to the mask by adjusting
the Oscilloscope vertical position and horizontal delay to obtain a PASS
on the Mask.
TELECOM MASK/MASK
LOAD SETUP 8 M1M2
PATTERN TRIGGER Trig’d
COMPARE
TEST ON
M1M2
AFTER FAIL CONTINUE
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