Garmin GNC 420A Installation Manual page 12

1.3.4 COM Transceiver Specifications (GNC 420 and GNS 430 Only) **
Regulatory Compliance
Audio Output
Audio Response
Audio Distortion
AGC Characteristics
Sensitivity
Squelch
Selectivity
Spurious Response
Transmitter Power
Transmitter Duty Cycle
Modulation Capability
Carrier Noise Level
Frequency Stability
Demodulated Audio Distortion
Sidetone
Demodulated Audio Response
* C37d Class 4 & 6 may not provide suitable COM transmit range for some high-altitude aircraft.
** Specifications shown apply at nominal input voltages of 13.75 Vdc or 27.5 Vdc, as applicable, and with
a nominal 50 ohm resistive load at the antenna connector.
Page 1-4
Page Rev L
TSO-C37d Class 4 & 6* (3 & 5 for "A" models), TSO-C38d
Class C & E, JTSO-2C37e, JTSO-2C38e, RTCA DO-186a
ICAO Annex 10 Volume III (Part II – Voice Communications
Systems) Par. 2.3.3
100 mW minimum into a 500 Ω load.
Less than 6 dB of variation between 350 and 2500 Hz.
The distortion in the receiver audio output shall not exceed
15% at all levels up to 100 mW.
The audio output shall not vary by more than 6 dB when the
level of the RF input signal, modulated 30% at 1000 Hz, is
varied from 5 µV to 450,000 µV.
(S+N)/N on all channels shall be greater than 6 dB when the
RF level is 2 µV (hard) modulated 30% at 1000 Hz at rated
audio.
2 µv ±6 dB for 25 kHz channels.
3 µv ±6 dB for 8.33 kHz channels.
6 dB BW is greater than ±8 kHz for 25 kHz channeling.
60 dB BW is less than ±25 kHz for 25 kHz channeling.
6 dB BW is greater than ±2.778 kHz for 8.33 kHz channeling.
60 dB BW is less than ±7.37 kHz for 8.33 kHz channeling.
Greater than 85 dB.
At Least 10 watts, 16 watts for "A" models
Recommended 10% maximum.
The modulation shall not be less than 70% and not greater
than 98% with a standard modulator signal applied to the
transmitter.
Shall be at least 45 dB (S+N)/N.
0.0005%
Less than 10% distortion when the transmitter is modulated
at least 70%.
into a 500 Ω load when the transmitter is modulated
1.4 V
RMS
at least 70%.
Shall be less than 6 dB when the audio input frequency is
varied from 350 to 2500 Hz.
400 SERIES INSTALLATION MANUAL
P/N 190-00140-02