HP HP 8753E, User Manual, Page: 426 / 699

Forward transform
range. In the forward transform (from CW time to the frequency domain),
range is as the frequency span that can be displayed before occurs, and is
to range as defined for time domain measurements. In the range formula, substitute
time span for frequency span.
Example:
Range =
Number
of
points
1
time span
1
= 200 x
= 1000
Hertz
For the example given above, a 201 point CW time measurement made over a 200 ms time
span, choose a span of 1 or less on either side of the center frequency (see Figure 6-80).
That is, choose a span of 2 or less.
Figure Range of a Forward Transform Measurement
increase the frequency domain measurement range, increase the span. The
range is inversely proportional to the sweep time, therefore it may be necessary to increase
the number of points or decrease the sweep time. Because increasing the number of points
increases the auto sweep time, the range is 2 on either side of the selected CW
time measurement center frequency (4 span). lb display a frequency span of
4 enter the span as 4000 Hz.
Application and Operation Concepts