Infrared Technology Overview
Infrared or “IR” technology uses infrared light to transmit audio without wires. This type of transmission is advantageous to RF transmission because it is secure, it is not susceptible to RF interference, and one receiver can be used for multiple rooms within a facility. The transmitter accepts an audio signal and then frequency modulates an RF carrier at 2.3, 2.8, 3.3 and/or 3.8MHz. This carrier along with DC power (to power the radiator) is supplied to the radiator via cables. The carriers are then radiated into the room using IR emitter diodes. This is the same technology used by the remote control of your TV set. A receiver then receives the IR light and demodulates the carrier.
DesignDesign GuideGuide
Radiator | 1 | 2 | 3 | 4 |
Audio Source
Receiver
IR Transmitter
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IURPWKHUDGLDWRULWZLOOQRWUHFHLYHWKHDXGLRVLJQDO,WLVLPSRUWDQWWRSURYLGHVXIÀFLHQW,5FRYHUDJHZLWKLQ a facility so users will not have drop outs of the IR signal. This design guide will help you do this.
,QIDFLOLWLHVWKDWKDYHUHÁHFWLYHDQGOLJKWHUFRORUHGVXUIDFHVWKH,5OLJKWZLOOEHUHÁHFWHGDQG\RXFDQ achieve greater coverage. For example, when emitting in a very large room (like an exhibit hall) you will notice that you need to point the receiver directly at the radiator to pick up the signal. However, when the radiator is placed in a smaller room (for example 50 ft2/14.6 m2 square) with white walls you will
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directions, increasing coverage.
•Listen systems use higher modulation frequencies that make the system less susceptible to light
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interference from sources that create IR light such as sunlight and plasma displays.
•Listen products are compatible with other manufacturers who use the same modulation frequencies (2.3, 2.8, 3.3, 3.8 MHz).
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