Garmin GNC 420, Руководство по обслуживанию

Страница: 78 / 168

400 SERIES MAINTENANCE MANUAL Page 5-27
P/N 190-00140-05 Rev. C
5.7.3.6 Receiver Quieting
1. Apply a -86 dBm RF level to the RF input.
2. Apply a Standard VOR Audio Test signal at 108.00 MHz.
3. Measure at the 500
:
VOR/ILS AUDIO HI J6-16 and 500
:
VOR/ILS AUDIO LO J6-17
outputs.
4. Verify the Audio SINAD or SNR is greater than 25 dB.
Audio SINAD________> 25 dB
5.7.3.7 Ident/Voice Tone Ratio
1. Apply a -67 dBm RF level to the RF input.
2. Apply a Standard VOR Audio Test signal with modulation frequency of 1020 Hz at
108.00 MHz.
3. Measure at the 500
:
VOR/ILS AUDIO HI J6-16 and 500
:
VOR/ILS AUDIO LO J6-17
outputs, set to
a
7.07 Vrms.
4. Toggle between IDENT mode and VOICE mode and verify the ident/voice ratio is greater
than 20 dB.
Ident/Voice Ratio __________ > 20 dB
5. Apply a Standard Localizer Audio Test signal with modulation frequency of 1020 Hz at
108.10 MHz.
6. Measure at the 500
:
VOR/ILS AUDIO HI J6-16 and 500
:
VOR/ILS AUDIO LO J6-17
outputs.
7. Toggle between IDENT mode and VOICE mode and verify the ident/voice ratio is greater
than 20 dB.
Ident/Voice Ratio________> 20 dB
5.7.3.8 Harmonic Distortion
1. Apply a -53 dBm signal amplitude modulated 30% at 1 kHz (IDENT Mode Selected).
2. Measure at the 500
:
VOR/ILS AUDIO HI J6-16 and 500
:
VOR/ILS AUDIO LO J6-17
outputs, and set to 7.07 Vrms.
3. Verify the total harmonic distortion is less than 5%.
THD______< 5%