DESIGN AND CONSTRUCTION OF A WIRELESS LOUDSPEAKER
CHAPTER ONEÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
INTRODUCTION
1.1Â Â Â Â Â Â PREAMBLES
Wireless speakers are very similar to traditional loudspeakers that are wired, but they transmit audio signals using radio frequency (RF) waves rather than over audio cables. As things stands today, the term ‘wireless’ in the audio and video world does not mean ‘wireless’ – rather all it means is less wires. And this applies to any wireless speaker system presently. Still, this in itself can turn out to be a great advantage. Home audio systems can be enhanced and made more versatile by incorporating the ability to listen to music from a single source in multiple locations. However, distributing music throughout the homes, theaters, churches, stadiums, arenas, and broadcast facilities has proved to be logistically difficult (Syafiqah, 2010). Home owners could extend the listening range of an audio source by purchasing a multi-room amplifier and having additional wiring installed through-out the house by a professional electrician. However, for many consumers who do not own their homes or who cannot afford such an upgrade, this solution would be impractical. The alternative of having interconnecting wires laid out visibly throughout the home has also been unappealing to most consumers for reasons of safety and aesthetics. Therefore, the lack of an available, affordable technology that would overcome the need for wired audio device interconnection greatly restricted the home audio possibilities for most people. Recently, wireless systems have become available that offer home wide music distribution that is in many cases more practical and more elegant than the wired methods previously mentioned Using wireless communication technology for home entertainment becomes popular.
Wireless speaker system is not a new invention for this century; however, the goal of this project is to improve the size, quality and range of the communication system. Here, wireless speakers are composed of two units: a main speaker unit combining the loudspeaker itself with an RF receiver, and an RF transmitter unit (Syafiqah, 2010). There is normally an amplifier integrated in the speaker’s cabinet because the RF waves alone are not enough to drive the speaker. This integration of amplifier and loudspeaker is known as an active loudspeaker. Manufacturers of these loudspeakers design them to be as lightweight as possible while producing the maximum amount of audio output efficiency. Wireless speakers still need power, so require a nearby AC power outlet, or possibly batteries (DC). Only the wire to the amplifier is eliminated.
The transmitter connects to the audio output of audio devices like speakers. Wireless technology is relatively new for home surround sound systems as well as other systems. There are two types of transmission media for wireless speakers. RF signal based systems, and infrared signal based systems. RF, or radio frequency based systems use radio signals to transmit data, and in this case music, to the remote receiver. RF systems commonly use radio frequencies between 300 MHz and 1000 MHz, with 900 MHz being the most common frequency. Transaction rates range up to 40,000 bits per second (Binti, 2011).
