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There are actually only 3 main frequency bands in which current cord-less speakers function: 900 MHz, 2.4 GHz and 5.8 GHz. Rising rivalry in these frequency bands has caused makers to develop completely new techniques that can manage the higher interference, one of which I will show you in this article.
Adaptive frequency hopping is a strategy which provides a large degree of robustness against interference for outdoor cordless speakers. It works by checking all of the channels within the working frequency band. After that it confirms which of the available channels are used by different cordless gadgets.
Those busy channels are tagged. From the other free channels, a hop set is constructed. This hop set is a selection of unoccupied channels. During the broadcast, each one of the hop-set frequency channels are employed. Every channel is employed for a short period of time (also referred to as "burst"). After that time, the transmitter and receiver switch to the following hop-set channel. The cord-less receiver similarly changes to the next channel such that the transmitter and receiver are constantly transmitting and receiving on the identical frequency channel. In order for the transmitter and receiver to be in sync, both transmitter and receiver communicate the hop set with each other.
The transmitter keeps checking every one of the available channels even after the hop set is set up so that it has a quantity of extra frequency channels available which can substitute any working frequency channel which gets occupied by a different transmitter. Having a catalog of backup frequency channels allows the hop set to be modified very quickly and consequently this strategy works very well in preventing interference and furthermore in minimizing broadcasting at busy channels.
Data buffering is another approach in order to boost the quality of service of wireless real-time music broadcast. Data buffering was designed to cope with loss or destruction of packets due to very poor reception or multipath fading. The transmitter adds a cyclic redundancy check (CRC) to each packet and also retains a specific amount of packets inside a storage buffer. Utilizing the CRC, the receiver has the capacity to figure out whether or not a packet was compromised. The packet counter allows the receiver to ascertain whether any packets have been lost. In each case, the receiver is going to request the missing or damaged packet to be resent by transmitting a signal to the transmitter. Asking for packet retransmits necessitates the receiver to have transmit capability. Considering that requests for packet retransmits usually can only be delivered during specified time slots in the course of the protocol, the number of receivers which are supported for each transmitter is limited.
Posted on: 12:32 PM - 05 Sep 12
| What Transmission Standards Are Being Used By Wireless Speakers page created by Patrick Hall |
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