HP 8642A Operation And Calibration Manual page 96

Operation
Model 8642A/B
RF Frequency Sweep (cont'd)
3-60
How to Set Sweep Time for Phase Continuous Frequency Sweep (Special Function 123)
(llnderstanding Limitations Between Sweep Spans and Sweep Times; Also, How
to
Set a Specific
Number
of
X-Axis Steps)
The operating characteristics for sweep time are as follows:
Minimum Sweep Time
Maximum Sweep Time
Sweep Time Resolution
Refer to calcula bon # 3 on page 3 - 61
. Refer to calculation #4 on page 3 - 61
1
111S
Since this lype of frequency sweep sweeps in a phase continuous manner, no frequency
steps are used (although the X-axis output still uses steps). However, you might want to
choose frequency span and sweep time so each allows the other's
settiI~gs
(as descflbed on
page 3 - 5 2) Also, you can calculate X -axis steps (a vaila hIe at the rear -panel output).
The information that follows will enable you to calculate
1)
the minimum sweep span for a desired sweep tim" and frequency band (page 3-61),
2) the maximum sweep span for a desired sweep t.ime and frequency band (page 3-61),
3) the minimum sweep time for a desired sweep span and frequency band (page 3- 61),
4) the maximum sweep time for a desired sweep span and frequency band (page 3-61),
5) the number of automatically selected X-axis steps based on a sweep time setting
(page 3-62), and
6) the required sweep time to select a specific number of X-axis steps (page 3-62)
Since some of the calculations below use the frequency band divide number, the number
for each band is listed in the following table
Band RF Frequp.ncy Range Divide Number
10 1057.500001 to 2115.000000 0.5
(86428 only)
9 528.750001 to 1057.500000 1
8
264.375001 to 528.750000
2
7
132.187501 to 264.375000
4
6
66.093751 to
132.187500 8
5 33.046876 to 66.093750 16
4 16.523438 to 33.046875 32
3
8.261719 to
16.523437 64
2
4.130860 to 8.261718
128
1
0.100000 to 4.130859
16
He!
0.100000 to 132.187500
1
If the frequency span is not possible from a divide band but WOllld be possible if the Het
band was used, the Signal Generator will automatically select the Het band (if Special
[-"unction 8, Pref er Heterodyne Band, is not selected) However, if the dIvide hand or the
Het band could be used, the Signal Generator will select the divide bane]. lor example, if
a sweep setting of 120.0 to 120.4 ME! is selected, the Signal Generator will
automatically select the heteroc\yne band because a
400
kHz span is not possible in Band
6. But if a sweep setting of 12000 to 12003 l\.lI-fz is selected, the SIgnal C;enerator will
automatically select band 6. (Refer to Hi'" Frequency, page 3- 39, for more information
about the divide bands and the heterodyne band)