Listen Technologies 863 MHz Portable Radio User Manual


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Design Guide
Frequency Modulation (FM) Technology Overview
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This same technology is used by local FM radio stations to broadcast voice and music. FM signals can travel
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frequency. This section of the manual will help you design a system that will get the best range with the least
amount of interference.
Microphone
FM Transmitter
Receiver
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• Multipath
Multipath interference is a form of RF interference that occurs when radio signals have more than one path
between the receiver and the transmitter causing the two RF signals to add out of phase. This could occur in areas
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and out of squelch when the receiver is moved. Portable applications are much more susceptible to multipath
than those that are stationary. Multipath distortion is often worse as the distance between transmitter and receiver
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• Antenna Positioning
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