Garmin GNC 420, Руководство по обслуживанию

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400 SERIES MAINTENANCE MANUAL Page 5-39
P/N 190-00140-05 Rev. C
5.7.5.6 Centering Accuracy
1. Apply a standard glideslope test signal to the unit.
2. Measure GLIDUP (J6-32) with respect to GLIDDOWN
(GLIDESLOPE Common) (J6-31).
3. Verify the centering accuracy is 0 mV
r
7.8 mV.
Centering Accuracy _________mV
5.7.5.7 AGC
1. Apply a glideslope centering test signal to the unit.
2. Measure GLIDUP (J6-32) with respect to GLIDDOWN
(GLIDESLOPE Common) J6-31 to find the course deviation.
3. Vary the RF input level between -76 dBm and -33 dBm.
4. Verify the course deviation is 0
r
7.8 mV
Course Deviation _________mV
5. Apply a glideslope deviation test signal to the unit.
6. Measure GLIDUP with respect to GLIDDOWN (GLIDESLOPE
Common) J6-31 to find the course deviation.
7. Vary the RF level between -76 dBm and -33 dBm.
8. Verify the course deviation is 78
r
7.8 mV.
Course Deviation ______mV
5.7.5.8 Selectivity (Bandwidth)
1. Apply the glideslope centering test signal at a level of -87 dBm.
2. Vary the RF frequency
r
17 kHz from the assigned channel.
3. Measure GLIDUP with respect to GLIDDOWN (GLIDESLOPE
Common) J6-31 to find the course deviation.
4. Verify the course deviation is 0 mV
r
7.8 mV.
Course Deviation ______mV @ +17 KHz
Course Deviation ______mV @ -17 KHz