User's Manual Part 2

RVP8 User’s Manual
April 2003
TTY Nonvolatile Setups (draft)
3–12
three available slave DSPs would be reduced to two; whereas on a dual-board system,
the 13 available DSPs would be reduced to 12. Obviously, the percentage penalty is
less in a larger system.
The second question decides how the overall dynamic range of the receiver will fit
into the 12-bit unipolar output voltage span of the DAC that produces the LOG Video
waveform. The default setting calls for the upper 100dB of dynamic range to occupy
85% of the output voltage span. This means that the strongest IF input signal would
produce 85% of the maximum DAC voltage (approximately 2.55 Volts); 50dB down
would be 42.5%, and 100dB down would be 0%, i.e., zero volts.
If you are using a self-triggering LOG Video waveform, then the 15% of headroom
provided by the default settings leaves room for the embedded trigger pulse.
However, if your RVP8 has the hardware modification required to synchronize the
LOG Video to the system trigger, then the full 100% of the DAC voltage span can
freely be used. The third setup question can be used to force freerunning mode on an
RVP8 that has the hardware modification. This question is included mostly for
testing purposes.
The last question only appears in dual-receiver mode. Answer “Yes” if you would
like the LOG video analog output signal to be based on the data from the secondary
receiver rather than from the primary receiver.
Scope plots– Holdoff ratio: 0.50, Stroke: 1000.0 usec
The oscilloscope plotting commands are described in Chapter 4. This question
allows you to vary the amount of holdoff time that is inserted between each drawing
stroke, as well as the stroke length itself. Try increasing the holdoff if your scope is
not triggering reliably. Longer holdoffs make it easier for the scope to find the initial
trigger point, but may introduce visible flicker. To reduce flicker, try decreasing the
stroke duration from its default value of 1000 microseconds.
Limits: Holdoff 0.05 to 5.00, Stroke 100 to 10000 msec.
PWINFO command enabled: No
The “Pulsewidth Information” user interface command can be disabled, thus further
protecting the radar against inappropriate combinations of pulsewidth and PRF. This
is a more safe setting in general, and is even more important when DPRT triggers are
being generated. It can also be useful when running user code that is not yet fully
debugged.
TRIGWF command enabled: NO
The “Trigger Waveform” user interface command can be disabled if you want to
prevent the host computer from overwriting the RVP8’s stored trigger specifications.
This is the default setting, based on the assumption that the built-in plotting
commands would be used to configure the triggers. Answering “YES” will allow
new waveforms to be loaded from the host computer.
RVP7 Emulation: No
The RVP8 implements a reasonably precise emulation of the RVP7 command set.
This mode is useful because it allows an RVP8 to be plugged directly into a software
system that used to run with an RVP7. All of the configuration steps that are new and