FCC has ruled that the operation of wireless microphones in the 700 MHZ BAND is prohibited after June 12, 2010. Those frequencies will be used for public safety.
Archive for the ‘Audio/Video’ Category
Wireless microphones – 700 MHZ band prohibited
June 10, 2010Infrared Assistive Listening Systems: Comparison and Recommendations
June 10, 2010
Source: Sennheiser Practical Applications in Infra-Red Technology, 2000
Infrared Assistive Listening Systems (ALS) transmit audio and provide better privacy than other technologies such as FM. Currently there are no standards for Infrared ALS, thus a general understanding of Infrared ALS technology and hands-on evaluations are necessary when determining an infrared solution to implement. The purpose of this paper is to provide recommendations for a future cost-effective implementation of an Infrared ALS by comparing three leading Infrared ALS.
Technology Background
Infrared ALS transmit audio using invisible infrared light waves (Bakke, Levitt, Ross & Erickson, 1999). This form of transmission delivers high quality audio and provides better privacy than other ALS technologies. An Infrared ALS has three components:
- Modulator (Transmitter): Processes the audio signal from a signal source for infrared transmission
- Radiator (Emitter): Produces infrared light that is radiated into a room to transmit the audio
- Receiver: Converts the infrared light signal back to an electrical signal and headphones on the receiver deliver the audio signal to the user
Posted courtesy of Jorge Ovando Zalapa
