VXI VT1433B, User Manual, Page: 55 / 203

Base Sample Rates
Baseband Measurement Spans
The table on the following page shows the measurement spans available for base
sample rates, for baseband measurements.
“Fs” is the sample frequency or sample rate. The value for zero divide-by-two
steps and no divide-by-five step is the top measurement span corresponding to the
sample rate. This is with no decimation and using 400 lines to avoid alias. The
other values on the table are for this top span decimated by five and/or two.
For a VT1433B which has option 1D4, the Arbitrary Source, the sample rate for
the source is automatically set to be the same as the sample rate selected for the
inputs. When the source is active the sample rate cannot be greater than
65.536 kHz.
Decimation Filter Diagram
The drawing below illustrates the way the spans in the table are generated. In
the case of baseband spans (lower limit of span fixed at zero), the frequency can
(optionally) be divided by five and then (optionally) divided by two up to eight
times.
VT1433B User's Guide
Using the VT1433B
3-17
ADC
zero or
one time
zero or
sixteen times
÷5
÷2
Figure 3-6: Decimation filter diagram - baseband