Wireless audio is becoming popular. Numerous consumer products for example wireless speakers are cutting the cable and also offer greatest freedom of movement. I will investigate how newest wireless technology are able to cope with interference from other transmitters and how well they will perform in a real-world scenario.
The most popular frequency bands which are used by wireless gadgets include the 900 MHz, 2.4 Gigahertz and 5.8 GHz frequency band. Mainly the 900 MHz and also 2.4 Gigahertz frequency bands have started to become crowded by the ever increasing amount of gadgets including wireless speakers, cordless phones etc.
Just switching channels, however, is no dependable remedy for avoiding certain transmitters that use frequency hopping. Frequency hoppers which include Bluetooth products or several wireless phones will hop through the entire frequency spectrum. Hence transmission over channels is going to be disrupted for short bursts of time. Therefore today's sound transmitters incorporate special mechanisms to cope with interfering transmitters to ensure steady interruption-free audio transmission.
One of these strategies is called forward error correction or FEC in short. The transmitter will transmit extra data in addition to the sound data. Using this supplemental information, the receiver can easily recover the original data whether or not the signal was damaged to some extent. Transmitters making use of FEC on its own generally can broadcast to any number of cordless receivers. This mechanism is normally used by systems where the receiver can't resend information to the transmitter or in which the number of receivers is rather large, just like digital stereos, satellite receivers etc.
An additional approach uses receivers which transmit data packets to the transmitter. The data packets have a checksum from which each receiver can easily decide if a packet was received properly and acknowledge proper receipt to the transmitter. If a packet was damaged, the receiver is going to notify the transmitter and request retransmission of the packet. As a result, the transmitter has to store a certain amount of packets in a buffer. Equally, the receiver will have to have a data buffer. Employing buffers leads to a delay or latency in the transmission. The amount of the delay is proportional to the buffer size. A larger buffer size increases the dependability of the transmission. Video applications, nevertheless, require the audio to be synchronized with the movie. In cases like this a big latency is a problem. One constraint is that systems where the receiver communicates with the transmitter usually can just broadcast to a few cordless receivers. Also, receivers have to incorporate a transmitter and usually consume additional current
Often a frequency channel may become occupied by another transmitter. Ideally the transmitter can recognize this fact and switch to yet another channel. To achieve this, some wireless speakers continuously check which channels are available to enable them to immediately change to a clear channel. The clear channel is selected from a list of channels that was identified to be clear. One technology which utilizes this transmission protocol is named adaptive frequency hopping spread spectrum or AFHSS
The most popular frequency bands which are used by wireless gadgets include the 900 MHz, 2.4 Gigahertz and 5.8 GHz frequency band. Mainly the 900 MHz and also 2.4 Gigahertz frequency bands have started to become crowded by the ever increasing amount of gadgets including wireless speakers, cordless phones etc.
Just switching channels, however, is no dependable remedy for avoiding certain transmitters that use frequency hopping. Frequency hoppers which include Bluetooth products or several wireless phones will hop through the entire frequency spectrum. Hence transmission over channels is going to be disrupted for short bursts of time. Therefore today's sound transmitters incorporate special mechanisms to cope with interfering transmitters to ensure steady interruption-free audio transmission.
One of these strategies is called forward error correction or FEC in short. The transmitter will transmit extra data in addition to the sound data. Using this supplemental information, the receiver can easily recover the original data whether or not the signal was damaged to some extent. Transmitters making use of FEC on its own generally can broadcast to any number of cordless receivers. This mechanism is normally used by systems where the receiver can't resend information to the transmitter or in which the number of receivers is rather large, just like digital stereos, satellite receivers etc.
An additional approach uses receivers which transmit data packets to the transmitter. The data packets have a checksum from which each receiver can easily decide if a packet was received properly and acknowledge proper receipt to the transmitter. If a packet was damaged, the receiver is going to notify the transmitter and request retransmission of the packet. As a result, the transmitter has to store a certain amount of packets in a buffer. Equally, the receiver will have to have a data buffer. Employing buffers leads to a delay or latency in the transmission. The amount of the delay is proportional to the buffer size. A larger buffer size increases the dependability of the transmission. Video applications, nevertheless, require the audio to be synchronized with the movie. In cases like this a big latency is a problem. One constraint is that systems where the receiver communicates with the transmitter usually can just broadcast to a few cordless receivers. Also, receivers have to incorporate a transmitter and usually consume additional current
Often a frequency channel may become occupied by another transmitter. Ideally the transmitter can recognize this fact and switch to yet another channel. To achieve this, some wireless speakers continuously check which channels are available to enable them to immediately change to a clear channel. The clear channel is selected from a list of channels that was identified to be clear. One technology which utilizes this transmission protocol is named adaptive frequency hopping spread spectrum or AFHSS
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