8.13 Define Trigger Generator Waveforms
(TRIGWF)
Do not use TRIGWF in any new code applications that drive RVP900.
Use the interactive trigger setup procedure to define RVP900 triggers and timing. See
6.5 Pb — Plot Burst Pulse Timing (page 132).
CAUTION!
TRIGWF is obsolete . It is included for backward compatibility with RVP6. The code is
disabled by default.
RVP900 has a built-in trigger generator that can synthesize 6 independent digital output
waveforms, each having arbitrary shape and being active anywhere in a window centered
around zero-range.
The trigger outputs can be defined by a 2048-word by 6-bit table which is loaded from the
user computer. The patterns are automatically read from the table and output to the 6
trigger lines during each radar pulse.
The outputs can be used for transmitter triggers, scope triggers, range strobes, PLL gates,
and so on. The writable waveform table is unique, in that the detailed timing of trigger and
related control signals can be easily adjusted in software, without having to resort to
reprogramming PROMs. This makes it possible for user software to edit the trigger timing
interactively.
Trigger waveforms are loaded using the TRIGWF command. Four bits in the command word
(PW0 ... PW3) select which pulse widths receive the new waveforms. On power-up, the
pulse widths are initialized to user-selected waveforms.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
---------------------------------------------------------------
| | | | | | | | | | | | | | | | |
| |PW3|PW2|PW1|PW0| | 0 1 1 0 1 | Command
|---------------|---|---|---|---|------------|-------------------|
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
---------------------------------------------------------------
| | | | | | | | | | | | | | | | |
| H | | Transition Point of POLAR0 Control Line | Input 1
|-------------------|--------------------------------------------|
The H bit defines the sense of the control line when horizontal polarization is selected.
Inputs 2 ... 2049, indicate bits output every 7.195 MHz and Input 1025 corresponds to
the time at which data at range zero are sampled.
Chapter 8 – Host Computer Commands
293
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