USER’S MANUAL__________________________________________________________________
144 _________________________________________________________________ M211322EN-D
Typing Q or ESC exits the plot command entirely (as they normally do).
All other keys return the plot command to its normal live updating, but the
key is otherwise discarded (that is, subcommand keys are not executed
while exiting from single step mode).
All of the plot commands support subcommands where the only purpose is
to alter the appearance of the display, for example, zoom, stretch, etc.
These subcommands make no changes to the actual working RVP900
calibrations. However, the display settings are stored in nonvolatile RAM,
just like all of the other setup parameters. This means that all previous
display settings are restored whenever you restart each plot command. This
is very convenient when alternating among the various plots.
The Pb, Ps, and Pr commands are intended to be used together for the
combined purpose of configuring the RVP900 digital front end. You may
run any of the commands at any time, but the following procedure may be
used as a guideline for first-time setups. The full procedure must be
repeated for each individual pulse width that the radar supports.
1. Use Mb to set the systems intermediate frequency (see Section 4.2.6
Mb — Burst Pulse and AFC on page 126).
2. Use Mt to choose the PRF and pulse width (see Section 4.2.4 Mt —
General Trigger Setups on page 114). Also, choose the range
resolution now, as it may constrain the design of the matched filter
later.
3. Use Mt0, Mt1, etc., to set the relative timing of all RVP900 triggers
that are used by the radar. Do not worry about the absolute values of
the trigger start times. Just setup their polarity and width, and their
start times relative to each other (see Section 4.2.5 Mt<n>— Triggers
for Pulsewidth #n on page 117). Make an initial guess of FIR filter
length as 1.5 times the pulse width.
4. Use Pb to slew the start times of all triggers so that the burst pulse is
properly sampled (see Section 5.3 Pb — Plot Burst Pulse Timing on
page 143). Refine the impulse response length if necessary so that all
samples easily fit within the display window.
5. Use Ps to design the matched FIR filter (see Section 5.4 Ps — Plot
Burst Spectra and AFC on page 148). Further refine the impulse
response length and passband width to achieve a filter that matches
the spectral width of the burst, and that has strong attenuation at DC.
If the FIR length is changed, return to Pb to verify that the burst is still
being sampled properly.
6. Continue using Ps and Mb to tune up the AFC feedback loop. The
settings that work for one pulse width should also work for all others.
7. Use Pr to verify that targets are being detected with good sensitivity
(see Section 5.5 Pr — Plot Receiver Waveforms on page 163).
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