User's Manual

RVP8 User’s Manual
October 2005
TTY Nonvolatile Setups
3–14
3.2.4 Mt — General Trigger Setups
These questions are accessed by typing “Mt” with no additional arguments. They configure
general properties of the RVP8 trigger generator
Pulse Repetition Frequency: 500.00 Hz
This is the Pulse Repetition Frequency of the internal trigger generator.
Limits: 50 to 20000Hz.
Transmit pulse width: 0
Limits: 0 to 3
Use external pretrigger: NO
PreTrigger active on rising edge: YES
PreTrigger is synchronous with IFD AQ clock: No
PreTrigger fires the transmitter directly: NO
When an external pretrigger is applied to the TRIGIN input of the RVP8, either the
rising or falling edge of that signal initiates operation. This decision also affects
which signal edge becomes the reference point for the pretrigger delay times given in
the “Mt<n>” section.
Answer the second sub-question according to whether the radar transmitter is directly
fired by the the external pretrigger, rather than by one of the RVP8’s trigger outputs.
In other words, answer “YES” if the transmitter would continue running fine even if
the RVP8 TRIGIN signal were removed. This information is used by the ”L” and
”R” subcommands of the ”Pb” plotting command, i.e., when slewing left and right to
find the burst pulse, the pretrigger delay will be affected rather than the start times of
the six output triggers.
Number of user–defined output triggers: 6
This setting defines the number of user–defined output triggers.
Limit: 12 (including polarization output controls)
Number of polarization output controls: 2
This setting defines the number of polarization output controls.
2–way (Tx+Rx) total waveguide length: 0 meters
Use this question to compensate for the offset in range that is due to the length of
waveguide connecting the transmitter, antenna, and receiver. You should specify the
total 2-way length of waveguide, i.e., the span from transmitter to antenna, plus the
span from antenna to receiver. The RVP8 range selection will compensate for the
additional waveguide length to within plus-or-minus half a bin, and works properly at
all range resolutions.
POLAR1 is high for vertical polarization : NO
POLAR2 is high for vertical polarization : NO
These questions define the logical sense of the two polarization control signals
POLAR1 and POLAR2. In a dual-polarization radar POLAR1 should be used to
select one of two possible states (nominally horizontal and vertical, but any other