P440 Data Sheet / User Guide
DRAFT
19
A copy of their paper can be found on the Time Domain website at the following link:
2.4.4 Bistatic Radar and Propagation with CAT (Channel Analysis Tool)
The CAT API and GUI allow the user to operate the P440 as either a bistatic radar or as a
communications propagation tool. This is easy because both applications are simply different ways
of viewing the same thing. Consider the waveform shown in
Figure 10
. A communications engineer
would look at this scan, point out the first arriving energy and comment that the multipath is due to
other reflectors in the channel. He might then use this waveform to compute the delay spread of the
channel and evaluate the impact of multipath on inter-symbol interference. A radar engineer would
look at this very same scan, point out the first arriving energy and comment that the multipath
reflections are due to a mix of fixed clutter and targets operating in the area. He might then use
Doppler processing or motion filters to separate the clutter from the targets.
Fig. 10: Captured waveforms can be used by either communications or radar engineers
Given this, it is best to ignore the application differences and focus on the functions provided by the
CAT API and GUI.
The API allows the user to transmit an arbitrary number of packets at a user-selectable
communications channel, over the antenna of choice, at a selected integration rate, at a selected
transmit power, and to receive packets from another unit. The receiver would then measure and
report the part of the waveform which the user is interested in evaluating. For example, the user
could request that the recorded waveform start 50 ns before the beginning of the pulse and end 145 ns
after the pulse (as shown in
Figure 10
). Note that this waveform was taken with a 61 ps resolution.
The CAT API also allows the user to specify other resolutions. For example, it is possible to take
waveforms at 4 ps intervals. Shown below in
Figure 11
and
Figure 12
are two waveforms. The only
difference between the two waveforms is that in one case the resolution was at 61 ps while the other
was taken at 4 ps.
