Garmin GNC 420, Руководство по обслуживанию

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Page 5-26 400 SERIES MAINTENANCE MANUAL
Rev. C P/N 190-00140-05
5.7.3.3 Voice/Ident Audio Distortion
1. Apply an input level from the RF generator of -79 dBm.
2. Modulate a standard VOR audio test signal at 350 Hz, 1000 Hz, and 2500 Hz (must be in
IDENT mode to pass 1000 Hz tone).
3. Measure 500
:
VOR/ILS AUDIO HI J6-16 with respect to 500
:
VOR/ILS AUDIO LO
J6-17.
4. Verify the combined distortion and noise in the receiver VOICE/IDENT audio output is not
greater than 10% at all levels up to 100 mW (7.07 RMS or 20Vpp).
Distortion_________ NGT 10%
5.7.3.4 VOR AGC
1. Apply a standard VOR audio test signal between the limits of -99 dBm and -13 dBm.
2. Measure 500
:
VOR/ILS AUDIO HI J6-16 with respect to 500
:
VOR/ILS AUDIO LO
(GND) J6-17 (must be in IDENT mode to pass 1000 Hz tone), set to
a
7.07 Vrms.
3. Verify the difference between the maximum and the minimum VOICE/IDENT audio output
levels is not greater than 3 dB.
Maximum and Minimum Output Level_________ NGT 3 dB
5.7.3.5 VOR Audio Sensitivity
1. Place unit in IDENT mode.
2. Apply a -103.5 dBm RF level to the RF input.
3. Apply a Standard VOR Audio Test signal at RF frequencies of 108.00 MHz, 112.50 MHz,
112.55, and 117.95 MHz.
4. 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.
5. Verify the Audio SINAD or SNR is greater than 6 dB.
Audio SINAD________> 6 dB