USER’S MANUAL__________________________________________________________________
380 _________________________________________________________________ M211322EN-D
C.15 Burst Pulse Alignment
Test Goal
Verify that the burst pulse is present and that its amplitude is sufficient.
This test also aligns the burst pulse in the burst pulse sample window.
Special Test Equipment
- KVM connected
Reference
- See Section 5.3 Pb — Plot Burst Pulse Timing on page 143
Test Procedure
1. Use ascope to select the desired pulse width at a save PRF.
2. In the TTY setups, use the "Mb" command to turn off burst pulse
tracking.
3. Set the transmitter to radiate.
4. Issue the "Pb" command to obtain the burst pulse display. Use the L/R
commands to find the burst pulse. Use the l/r commands to fine tune
the position of the burst pulse in the burst pulse window.
5. Adjust the width of the burst pulse window using the I/i command to
be slightly larger than the burst pulse (for example, ~50%).
6. Verify that the burst pulse power is in the range +1 to -12 dBm per the
tabular display on the setup terminal.
7. Record the burst pulse power:
Pulsewidth #0: _____________ dBm
Pulsewidth #1: _____________ dBm
Pulsewidth #2: _____________ dBm
Pulsewidth #3: _____________ dBm
8. Repeat the above procedure for each pulse width.
In the event that the burst pulse is not found, try to detect the burst pulse
on an oscilloscope connected directly to the IF burst line (ahead of the
RVP901). On a magnetron radar, if the AFC is not working, it is possible
the IF frequency is outside the RVP901 anti-aliasing filter bandwidth. It
may be necessary to go to manual frequency control to get this to work. If
no burst pulse is detected, the radar should be serviced by an experienced
technician. If the burst pulse power is too small or large, check the status
of any attenuators or amps in the burst pulse signal path. It might be
necessary to adjust the gain by installing a fixed attenuator or amplifier.
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