MIL-DTL-52872D
APPENDIX A
Test Method 2 - Continued.
synthesizer output, prior to the signal synthesizer air-coupled
output.
c.
Apply 30 (+0, -0.3) Vdc, through 2.7k ohms, to processor
terminals TB1-1 and TB1-2, and connect oscilloscope across these
terminals to monitor alarm function.
d.
With UMS in operation as in 2.1d., air-couple (closely spaced)
summed WUSG and synthesizer output signals to sound level meter
microphone.
e.
With Doppler signal synthesizer turned off, operate WSUG to
produce broadband ultrasonic noise. Adjust WUSG output level to
obtain a reading of 45 dB SPL on the sound level meter. This
broadband noise level shall be used in all subsequent steps
involving severe clutter.
f.
With the WUSG turned off, operate the Doppler signal synthesizer
in the steady-state mode at 0.55 fps. Adjust the signal
synthesizer output level to obtain a reading of 40 dB SPL on the
sound level meter (worst-case target return). This target
return signal level shall be used in all subsequent steps
involving target signals.
g.
Remove the air-coupled, summed signal-and-clutter output from
the sound level meter microphone and apply it to the transceiver
receive transducer.
h.
Turn off the WUSG; operating the Doppler signal synthesizer in
the pulsed mode, apply a 0.55 fps target signal (no clutter) for
a duration of 960 ms; the UMS shall alarm. Adjust the
transceiver range control to the lowest setting at which an
alarm can be obtained.
i.
Turn on the WUSG. Pulsing the synthesizer, apply 1.1 fps target
signal (severe clutter) for a duration of 780 ms. The UMS shall
alarm. If necessary, increase the range control to the setting
required to obtain an alarm. Do not decrease the range control
setting.
j.
Repeat step i. for a 2.2 fps target signal and a duration of 570
ms.
k.
Repeat step i. for a 4.4 fps target signal and a duration of 380 ms.
l.
Repeat step i. for a 8.8 fps target signal and a duration of 310 ms.
m.
Increase Doppler signal synthesizer output level to 55 dB above
RSPL. Repeat step i. for a 17.6 fps target signal and a
duration of 300 ms. The alarm duration, as indicated on the
oscilloscope, shall be from 0.5 to 1.5 seconds.
n.
Repeat step m. for -17.6 fps target signal.
2.2.2.
Background clutter with no target signals.
a.
Having performed 2.2.1, leave the transceiver range control at
the position to which it was set at the end of 2.2.1n.
b.
With the same test equipment configuration as in 2.2.1n. and the
same signal levels as in 2.2.1l., turn off the WUSG. The UMS
shall not alarm.
2.2.3.
Oscillating targets.
a.
Leave the transceiver range control as in 2.2.2 a.
b.
With the same test equipment configuration and signal levels as
in 2.2.1, turn off the WUSG.
c.
Operate the Doppler signal synthesizer in the steady state
oscillating mode, at 0.5 Hz, for a target velocity of 0.55 fps
(no clutter). The UMS shall not alarm.
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