Figure 32 Ambiguity Diagram of a Compressed Tx Pulse
Also shown in yellow and green are the Tx/Rx responses when the overall waveform is
modified by a 50 KHz target Doppler shift. Real weather targets would never have such a
large Doppler component, but the Pa menu allows you to study its eect anyway.
Frequency, Phase, and Amplitude of a Compressed Tx Pulse
The following
figure shows an alternate form of Pa plot of the same Tx waveform. The
horizontal axis again represents time, but now spans the entire duration of the pulse. Three
plots are drawn, and the vertical axis is interpreted
dierently in each case:
• The instantaneous frequency across the full length of the pulse is shown in white. The
vertical scale is normalized to hold the overall frequency span, which is also shown
numerically in the Pa TTY output.
• The waveform baseband phase is shown in green, and is normalized so that the vertical
axis holds the full span of values. Note that the phase, which generally spans a few
thousand degrees, is "unwound" in this plot so that you can see its behavior.
• The amplitude of the Tx waveform envelope is shown in yellow. It is drawn using a linear
vertical scale which occupies only the middle half of the plot. This is to avoid creating
too much "plotting clutter" in the corners.
Chapter 6 – Plot-assisted Setups
161
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