NAVAIR 17—2OAX—737
4.4 DEMOD TONES AND DC OFFSET TESTS
4.4.1 Set the TI controls as follows:
BEARING-FREQ switch to
FREQ
MASTER MOD control to
CAL (UNCAL lamp off)
1020 Hz indent tone MOD control to
CAL (UNCAL lamp off)
9960 Hz FM tone MOD control to
CAL (UNCAL lamp off)
30 Hz tone MOD control to
CAL (UNCAL lamp off)
LOC DDM switch to
0
G/S DDM switch to
0
4.4.2 Connect the oscilloscope vertical amplifier input to the TI rear panel DEMOD jack. Connect the
DMM voltage input to the TI rear panel TONES jack.
4.4.3 Set the TI oscilloscope and DMM controls as necessary to measure the TI signals in the following
steps:
4.4.3.1 Set the TI FREQUENCY MHz switches to 108.100 MHz. Ensure that the TI frequency display
indicates 108.100, and the LOC mode indicator is on.
4.4.3.2 Set the TI G/S DDM switch to 90 Hz, and ensure that the 150 Hz tone off indicator is on.
4.4.3.3 Verify that the oscilloscope displays a 90 Hz tone, and that the DMM indicates between —40.0 and
+40.0 mV dc.
4.4.3.4 Set the TI LOC—G/S frequency switch to G/S.
4.4.3.5 Ensure that the TI frequency display indicates 334.700, and the G/S mode indicator is on.
4.4.3.6 Verify that the oscilloscope displays a 90 Hz tone, and that the DMM indicates between —40.0 and
+40.0 mV dc.
4.4.3.7 Set the TI G/S DDM switch to 150 Hz, and then ensure that the 90 Hz tone off indicator is on.
4.4.3.8 Verify that the oscilloscope displays a 150 Hz tone, and that the DMM indicates between —40 to
÷4OmVdc.
4.4.3.9 Set the TI LOC—G/S frequency switch to LOC.
4.4.3.10 Ensure that the TI frequency display indicates 108.100, the 90Hz tone off indicator is on, and the
LOC mode indicator is on.
4.4.3.11 Verify that the oscilloscope displays a 150 Hz tone, and that the DMM indicates between —40 to
+4OmVdc.
4.4.3.12 Set the TI G/S DDM switch to 0, and the FREQUENCY MHz switches to 108.000.
4.4.3.13 Ensure that the TI VOR mode indicator is on.
4.4.3.14 Verify that the oscilloscope displays a 9960 Hz tone, and that the tone is both frequency and
amplitude modulated with a 30 Hz tone.
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