HP 8591C, User Manual, Page: 83 / 373

Channel Measurements
Making Channel Measurements
Press DP TEST to determine whether the test meets the
FCC or NTC The FCC definition of differential phase (and
that of the NCTA) measures only the largest phase deviation from
the phase of the reference packet. The NTC
measures the
peak-to-peak deviation of phase from that of the reference packet.
The default is FCC (FCC is underlined) and changes are permanent
until changed by pressing DP TEST again. The status of
this key is reported on the results screen just below the results box.
The system mode differential phase test uses the current setting of
this switch when the test plan was created. Which test was used is
reported on the results table.
Press menu
Press # AVERAGES , enter the desired number of averages, then press
The default is 50 averages. The higher the number of averages,
the more consistent results when measuring low level signals. This value
is always returned to 50 when the test is entered.
Press CONTINUE to perform the test.
The result of the measurement is displayed on the analyzer display. See
Figure 2-25.
MAR 1995
EF 27.10
AT
I
A SB
CORR
. . . . . . ...'
MENU
TART
STOP MHz
3 MHz
Figure 2-25. Differential Gain/Differential Phase Measurement
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