HP 8360 - Manual (Page 211)

If the correction frequency span is only a subset of the start/stop
frequency span set on the source, no corrections are applied to the
portion of the sweep that is outside the correction frequency span.
The following example illustrates how the data is distributed within
the user flatness correction array.
Assume that the synthesizer is set to sweep from 2 to 18 but
you only enter user flatness correction data from 14 to 18
Linear interpolation occurs between the correction entries to provide
the 401 points required for the 14 to 18
portion of the array. No
corrections are applied to the 2 to 13.99 portion of the array.
Refer to Figure
Point Number 0 1200 1600
No Corrections Applied
P o i n t s
o f D a t a
Frequency
Corr. Freq.
Figure
Array Configuration when the Correction Data Frequency Span is a Subset of the
Synthesizer Frequency Span
Number of points interpolated between correction entries is
calculated as follows:
freq. span between correction entries
stop frequency start frequency
1600 1 = Number of pts
When correction frequencies are arbitrarily spaced, the number of
interpolated points varies.
When utilizing the user flatness correction feature, do not exceed the
synthesizer ALC operating range. Exceeding the ALC range causes
the output power to become unleveled and eliminates the benefits
of user flatness correction. The ALC range can be determined
by subtracting the minimum output power (-20
from the
maximum specified power. When the optional step attenuator is
ordered on a synthesizer with firmware released prior to November
1990, the attenuator needs to be uncoupled to obtain the full ALC
range. This can be accomplished by selecting POWER [MENU]
For example, an HP has an ALC range of
to -20
When user flatness correction is enabled, the maximum test
port power is equivalent to the maximum available leveled power
minus the maximum path loss
For example, if
an HP has a maximum path loss of 15 due to system
components between the source output and the test port, the test
port power should be set to -5
When user flatness correction
is enabled, this provides the maximum available power to the device
under test (DUT).
HP 8360
User’s Handbook
Operating and Programming Reference