Wireless audio is now popular. A multitude of consumer products such as wireless speakers are eliminating the cable and also promise ultimate freedom of movement. Let me investigate how newest cordless technology are able to deal with interference from other transmitters and just how well they will function in a real-world situation.
FM type audio transmitters are usually the least robust when it comes to tolerating interference because the transmission doesn't have any means to deal with competing transmitters. Having said that, those transmitters use a relatively constrained bandwidth and switching channels may steer clear of interference. Today's sound systems employ digital audio transmission and often function at 2.4 Gigahertz. These types of digital transmitters transmit a signal that takes up more frequency space than 900 MHz transmitters and thus have a greater potential for colliding with other transmitters.
FM type audio transmitters usually are the least reliable in regards to tolerating interference considering that the transmission doesn't have any method to deal with competing transmitters. Having said that, these types of transmitters possess a relatively restricted bandwidth and changing channels can frequently steer clear of interference. Digital audio transmission is usually employed by more sophisticated sound products. Digital transmitters usually work at 2.4 Gigahertz or 5.8 Gigahertz. The signal bandwidth is higher than 900 MHz transmitters and thus competition in these frequency bands is high. Quite a few wireless products like Bluetooth devices and also cordless phones use frequency hopping. As a result just switching the channel is not going to steer clear of those frequency hoppers. Real-time audio has fairly strict requirements relating to reliability and minimal latency. In order to provide those, additional mechanisms are required.
One approach is referred to as FEC or forward error correction. This approach will allow the receiver to fix a damaged signal. For this reason, supplemental information is transmitted by the transmitter. Using some innovative algorithms, the receiver is able to restore the data that may partly be corrupted by interfering transmitters. Consequently, these systems may transmit 100% error-free even when there exists interference. FEC is unidirectional. The receiver does not send back any kind of data to the transmitter. As a result it is usually employed for products including radio receivers where the quantity of receivers is big.
One of these methods is referred to as forward error correction or FEC for short. The transmitter will transmit additional information besides the sound data. Using a few advanced calculations, the receiver is able to fix the data which may partially be corrupted by interfering transmitters. Subsequently, these products can easily transmit 100% error-free even if there exists interference. FEC is unidirectional. The receiver doesn't send back any information to the transmitter. As a result it is often employed for products similar to radio receivers in which the quantity of receivers is large. One more method uses bidirectional transmission, i.e. every receiver transmits information back to the transmitter. This approach is only useful if the quantity of receivers is small. It also needs a back channel to the transmitter. The transmitters incorporates a checksum with each information packet. Every receiver can easily detect whether a certain packet has been acquired properly or disrupted because of interference. Subsequently, each wireless receiver will be sending an acknowledgement to the transmitter. Since dropped packets will have to be resent, the transmitter and receivers have to store data packets in a buffer. Using buffers leads to a delay or latency in the transmission. The amount of the delay is directly related to the buffer size. A larger buffer size enhances the reliability of the transmission. Video applications, however, require the sound to be in sync with the movie. In cases like this a large latency is difficult. Devices that integrate this kind of mechanism, nevertheless, are limited to transmitting to a small number of receivers and the receivers use up more energy.
To avoid crowded frequency channels, a few wireless speakers keep an eye on clear channels and may switch to a clean channel once the existing channel becomes occupied by a different transmitter. This method is also referred to as adaptive frequency hopping.
FM type audio transmitters are usually the least robust when it comes to tolerating interference because the transmission doesn't have any means to deal with competing transmitters. Having said that, those transmitters use a relatively constrained bandwidth and switching channels may steer clear of interference. Today's sound systems employ digital audio transmission and often function at 2.4 Gigahertz. These types of digital transmitters transmit a signal that takes up more frequency space than 900 MHz transmitters and thus have a greater potential for colliding with other transmitters.
FM type audio transmitters usually are the least reliable in regards to tolerating interference considering that the transmission doesn't have any method to deal with competing transmitters. Having said that, these types of transmitters possess a relatively restricted bandwidth and changing channels can frequently steer clear of interference. Digital audio transmission is usually employed by more sophisticated sound products. Digital transmitters usually work at 2.4 Gigahertz or 5.8 Gigahertz. The signal bandwidth is higher than 900 MHz transmitters and thus competition in these frequency bands is high. Quite a few wireless products like Bluetooth devices and also cordless phones use frequency hopping. As a result just switching the channel is not going to steer clear of those frequency hoppers. Real-time audio has fairly strict requirements relating to reliability and minimal latency. In order to provide those, additional mechanisms are required.
One approach is referred to as FEC or forward error correction. This approach will allow the receiver to fix a damaged signal. For this reason, supplemental information is transmitted by the transmitter. Using some innovative algorithms, the receiver is able to restore the data that may partly be corrupted by interfering transmitters. Consequently, these systems may transmit 100% error-free even when there exists interference. FEC is unidirectional. The receiver does not send back any kind of data to the transmitter. As a result it is usually employed for products including radio receivers where the quantity of receivers is big.
One of these methods is referred to as forward error correction or FEC for short. The transmitter will transmit additional information besides the sound data. Using a few advanced calculations, the receiver is able to fix the data which may partially be corrupted by interfering transmitters. Subsequently, these products can easily transmit 100% error-free even if there exists interference. FEC is unidirectional. The receiver doesn't send back any information to the transmitter. As a result it is often employed for products similar to radio receivers in which the quantity of receivers is large. One more method uses bidirectional transmission, i.e. every receiver transmits information back to the transmitter. This approach is only useful if the quantity of receivers is small. It also needs a back channel to the transmitter. The transmitters incorporates a checksum with each information packet. Every receiver can easily detect whether a certain packet has been acquired properly or disrupted because of interference. Subsequently, each wireless receiver will be sending an acknowledgement to the transmitter. Since dropped packets will have to be resent, the transmitter and receivers have to store data packets in a buffer. Using buffers leads to a delay or latency in the transmission. The amount of the delay is directly related to the buffer size. A larger buffer size enhances the reliability of the transmission. Video applications, however, require the sound to be in sync with the movie. In cases like this a large latency is difficult. Devices that integrate this kind of mechanism, nevertheless, are limited to transmitting to a small number of receivers and the receivers use up more energy.
To avoid crowded frequency channels, a few wireless speakers keep an eye on clear channels and may switch to a clean channel once the existing channel becomes occupied by a different transmitter. This method is also referred to as adaptive frequency hopping.
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