Garmin GNC 420, Руководство по обслуживанию

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400 SERIES MAINTENANCE MANUAL Page 5-7
P/N 190-00140-05 Rev. C
Standard VOR Audio Test Signal
Standard VOR audio test signal is a standard VOR test signal to which is added a 1000 Hz signal,
amplitude modulating the carrier 30%.
Standard Audio Test Signal
Standard audio test signal is a RF carrier amplitude modulated 30% at 1000 Hz. The RF input
signal shall be at a level of -53 dBm and have a frequency within 0.001% of the assigned carrier
frequency.
Standard VOR Deviation Signal
Standard VOR deviation signal is a standard VOR test signal in which the difference in phase
between the reference and variable phase signal is 10 (+/-0.3) degrees from the setting of the
equipment course selector. (This produces a NAV +LEFT output voltage of 150 millivolts
+/- 4.5 millivolts.)
Standard VOR Centering Signal
Standard VOR centering signal is a standard VOR test signal in which the difference in phase
between the reference and variable phase signal is equal (+/-0.3 degree) from the setting of the
equipment course selector.
5.4.5 Localizer Standard Signals
All RF input levels for the NAV receiver requirements are specified in dBm and do not require a
6 dB attenuator on the output of the signal generator provided the signal generator is calibrated
into 50 ohms.
5.4.5.1 Standard Test Signals
Unless otherwise specified, the RF input signals shall be at a level of -53 dBm and have a
frequency within 0.001% of the assigned carrier frequency in addition to the characteristics
outlined below. Note: ddm is the difference in depth of modulation. The absolute difference in
percentage of modulation of two tones divided by 100.
Standard Localizer Test Signal
Standard localizer test signal is an RF carrier amplitude modulated simultaneously by 90 and 150
Hz tones so that the sum of their separate modulation levels is 40%
r
1%. The tones shall have
the following characteristics:
a) they shall be phase-locked in such a manner that their voltage waveforms simultaneously pass
through zero in the same direction.
b) the maximum simultaneous variation in frequency shall not /-0.3%.
c) the total harmonic content of each tone shall not exceed 3%.
d) the RF level shall be -53 dBm and have a frequency within 0.001% of the assigned carrier
frequency unless otherwise specified.