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GNS 400W Series Maintenance Manual
Page 4-45
190-00356-05
Rev. A
NAV Audio Output Load (NAV AUDIO HI to NAV AUDIO LO)
The standard audio output load is 500 ohms, connected between NAV AUDIO HI J6-16 and
NAV AUDIO LO J6-17.
4.6.2 VOR 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 a 50 ohm load.
Standard Test Signals
Unless otherwise specified, the RF input signals must 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.
Standard VOR Test Signal
A standard VOR test signal is composed of two components:
An RF carrier, amplitude modulated 30% with a 9960 Hz signal that is frequency modulated at 30
Hz with a deviation ratio of 16 (frequency deviation of ± 480 Hz) for Reference phase (REF), and
variable phase (VAR) 30 Hz signal amplitude modulated 30% with respect to the reference phase
signal (REF). The RF input signal must be at a level of -53 dBm and have a frequency within
0.001% of the assigned carrier frequency.
Standard VOR Audio Test Signal
A 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
A standard audio test signal is a RF carrier amplitude modulated 30% at 1000 Hz. The RF input
signal must be at a level of -53 dBm and have a frequency within 0.001% of the assigned carrier
frequency.
Standard VOR Deviation Signal
A 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
A 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 degrees) from the setting of the
equipment course selector.
