Garmin GNC 420, Руководство по обслуживанию

Страница: 68 / 168

400 SERIES MAINTENANCE MANUAL Page 5-17
P/N 190-00140-05 Rev. C
5.7.2.5 Carrier Noise Level
1. Apply a standard MIC input signal.
2. The demodulated noise on the transmitter output, without audio modulation, shall be at least
45 dB below the demodulated audio level obtained when the transmitter is modulated with a
standard mic input signal.
118.50 MHz ______ > 45 dB
127.50 MHz ______ > 45 dB
136.50 MHz ______ > 45 dB
5.7.2.6 Demodulated Audio Distortion
1. Apply a standard mic input signal.
2.
Verify the combined total of distortion and noise in the demodulated output does not exceed
10% of the total demodulated output at modulation frequencies of 350, 1000, and 2500 Hz.
118.50 MHz ______ < 10%
127.50 MHz ______ < 10%
136.50 MHz ______ < 10%
5.7.2.7 Demodulated Audio Response
1. Adjust the mic input level for 200mV at 1000 Hz. This should produce approximately 70%
TX modulation.
2. Sweep the audio input frequency from 350 to 2500 Hz.
3. Verify the frequency response of the audio output does not vary more than 6 dB.
127.500 MHz (350 Hz) _________ dB
127.500 MHz (1000 Hz) _________ dB
127.500 MHz (2500 Hz) _________ dB