TM 1-6625-476-30
3-5
3-6. TEST DESCRIPTION. (CONT)
e. AUTOMATIC CONTROL MODULE (ACM) TEST. This test checks the ACM to ensure that the FLIR
can automatically adjust itself to the brightness and contrast of the target and the area around the target.
No adjustments are associated with the ACM test.
f.
NOISE EQUIVALENT TEMPERATURE DIFFERENCE (NETD)/MINIMUM RESOLVABLE
TEMPERATURE (MRT) TEST. The NETD test measures the RMS noise of the UUT in terms of
equivalent input target temperature change. The MRT test measures the minimum target temperature
change that is resolvable by the human eye in the displayed target image. There are no operator
adjustments.
g. SYSTEM INTENSITY TRANSFER FUNCTION (SIT) MAX & MIN TEST. This depot level test
measures the transfer function (output video to input temperature change) of the UUT and verifies its
dynamic range. It verifies that the maximum gain is sufficiently high to provide viewing of the minimum
required target temperature change. It also verifies that minimum gain prevents saturation of the
maximum required target temperature change. If the test results are out of tolerance, you will be directed
to perform channel balance.
h. ELECTRO-OPTIC NOISE (EON) TEST. This depot level test checks the video output for shading
when the UUT views a uniform temperature target mask. If the test results are out of tolerance, you will
be directed to perform channel balance.
i.
CHANNEL BALANCE TEST. This procedure is used to detect dead or noisy channels on the video
monitor. Routines built into the procedure direct you to perform replacements and/or adjustments as
necessary. Perform channel balance as follows:
(1)
Perform the full channel balance on all 180 channels when cooler/dewar A29/A30 has been
replaced.
(2)
Perform a partial channel balance on affected channels when dead or noisy channels have
been identified on the video monitor. Also perform a partial channel balance when preamplifier or
postamplifier CCAs have been replaced or moved.
Channel balance will only pass if the first and last channels adjusted are good channels. The program
will keep track of any bad channels that are encountered during adjustment, and will provide applicable
replacement instructions.
3-7. PRETESTING DATA.
Awareness of the following information will help you to successfully test the PNVS NSA, and may
prevent unnecessary termination of the test.
a. Noise. When power is applied to the scanner assembly and cooler/dewar assembly, they make a
considerable amount of noise. This is normal operation, and the program should not be terminated. Also,
the scanner assembly does not start at the same time as the cooler/dewar. This increases the operating
noise.
