Due to a shortage of very high frequency (VHF) communications frequencies, the FAA must use the same frequencies in different airspaces across the country. The geographical separation between ground transmitters is engineered to provide a desired signal that is at least 14 decibel (dB) above any co-channel signal the receiver may receive. The International Civil Aviation Organization (ICAO) recommends a greater 20-dB separation. This difference between the two signals is known as the desired to undesired (D/U) ratio. Tests performed on eight avionics receivers at the FAA Technical Center to compare receiver performance when exposed to 14- and 20-dB co-channel interference are described. It was concluded that at both D/U ratios, the receiver was able to reproduce clear, audible, and intelligible speech at both D/U ratios.
Comparison of 14 Decibels Versus 20 Decibels Desired to Undesired Signal Protection Ratios
1991
14 pages
Report
No indication
English
Policies, Regulations, & Studies , Radio & Television Equipment , Common Carrier & Satellite , Frequency control , Frequency ranges , Frequency standards , Radio frequencies , Radio signals , Signal reception , Signal to noise ratios , Very high frequencies , Airspace , Avionics , Civil aviation , Radio receivers , Radio transmitters
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