From the current situation, infrared wireless transmission technology is the most unfamiliar and least contacted by everyone. Most users who contact infrared wireless transmission are limited to the infrared function of slow speed on early smart phones. In fact, the application of infrared wireless technology Widely comparable to FM wireless technology, the TV remote control that is common in the home is a typical example, and infrared wireless technology is the oldest.
In technology applications, the most widely used infrared wireless technology is the remote control. Some of the early wireless mice were also wireless transmission technologies; with the maturity of infrared wireless technology, it is increasingly being used in high-end audio product solutions. Sennheiser's digital infrared microphones and Edifier's infrared wireless amplifiers are typical examples.
The remote control is the most common infrared device
The biggest advantage of wireless infrared technology is that it has a large bandwidth and even exceeds the other three mainstream wireless technologies. This means that audio products using infrared wireless technology can transmit large-capacity audio signals without compression, and the sound quality is better. Secondly, infrared It belongs to the light wave. Except for the strong light, there are few interferences that can affect the infrared wireless transmission work, and the stability is even more.
However, infrared wireless transmission technology has some shortcomings. For example, it has high requirements on directivity. It is easy for everyone to experience that the infrared remote control can not be operated with a slight deviation from the angle (currently the rambler's infrared wireless power amplifier has overcome this shortcoming through new technology. Secondly, the infrared wireless transmission has higher requirements on the transmission power. If the infrared wireless earphone driven by the battery is of little practical significance, finally, the wireless transmission distance is short, generally at a limit distance of about 10 meters.
Speaking of FM wireless technology, this may be one of the most mature wireless applications with the most comprehensive application and the lowest cost. The radio at your hand is the simplest FM wireless receiving device; some old analog phone phones are also used. FM wireless technology.
The radio is the most common FM receiver
In technology applications, most of the wireless headphones, some wireless speakers, and wireless microphones currently on the market use FM technology. From the perspective of the division of the radio spectrum, 76MHz-108MHz is the most common, while the U-high segment 800MHz is rare, and only Sennheiser wireless headphones and wireless microphones use this technology.
The reason why it is widely used is because FM technology has many advantages: First, its transmission distance is far, ordinary products can reach a distance of 20 to 30 meters, and the distance can be increased after changing the transmission power and receiving antenna sensitivity; FM can realize "broadcast" connection, that is, one transmitter can match multiple receivers after being adjusted to the same frequency, which is more suitable for the application of simultaneous translation equipment; finally, FM technology has strong penetration ability and is used by ordinary household users. More than enough, even if there is a wall blocking is not a problem.
Wireless microphones also use FM as the modulation mode.
In terms of shortcomings, the most fatal flaw of FM is that the confidentiality is not strong. The low-end 76MHz-108MHz FM signal can be captured by the radio, and the high-end 800Mhz microphone signal is also prone to harmonic interference, which is also the current popularity of cordless phones. One of the reasons for G technology; in addition, due to the limitation of transmission bandwidth, FM wireless technology generally has poor sound quality, and the sampling rate of up to 22KHz is called "radio sound quality"; finally, FM wireless technology is highly susceptible to interference and crosstalk occurs. And so on, the stability is not good.
Bluetooth technology, which is a wireless transmission protocol based on 2.4G technology, is different from other 2.4G technologies and is called Bluetooth technology.
For now, the most widely used Bluetooth technology is the Bluetooth headset. Since most mobile phones are integrated with Bluetooth, and some MP3 audio products also integrate Bluetooth modules, Bluetooth headsets have a wide range of "mass bases" and low cost of use.
The longest seen Jabra BT3030 Bluetooth headset
Due to the unique advantages of the Bluetooth headset, most Bluetooth wireless devices do not need to set up a transmitter, but only the Bluetooth headset can work, the cost of use is reduced; secondly, the Bluetooth headset has good confidentiality. This is determined by the frequency characteristics of 2.4G, which means that it is not easy to cause frequency hopping and harmonics to be eavesdropped. Finally, the current maturity of the Bluetooth headset is quite mature, and a good quality Bluetooth headset can be purchased for about 100 yuan, which is cost-effective.
Shengli SN-308 notebook speaker supports Bluetooth playback
The fatal drawback of Bluetooth technology is that it transmits a small amount of data, which can only reach about 1M per second. Even the two-channel Bluetooth headset that claims to listen to music design is also the case. The high and low frequency parts are severely compressed, and the reserved intermediate frequency part can only To achieve voice calls; in addition, Bluetooth technology needs to pay royalties, even if your Bluetooth headset is less than 100 yuan, the patent fee of 3-5 dollars is still "essential".
In fact, the application of this frequency band is more responsible: the same is the use of 2.4G frequency as the carrier, but the communication methods derived from different communication protocols will be very different; only in the amount of data transmitted, there are from 1M per second to 100M The difference per second.
Generally speaking, the 2.4G headset that the public thinks is a headset that uses 2.4G carrier and P2P communication protocol (hereinafter referred to as 2.4G technology) is different from Bluetooth headset. At present, 2.4G wireless transmission of P2P protocol can reach 2M data per second, while CD-level sound quality is only about 1.4M per second, so 2.4G can achieve lossless transmission.
Charm PC-4001 adopts 2.4G wireless transmission mode
Secondly, the 2.4G headphone has low requirements on the transmit power, which is relatively power-saving. Finally, the 2.4G technology can effectively increase the launch distance by increasing the power and improving the receiving sensitivity. The distance of more than 100 meters can be easily realized.
The charm flagship PC91 still uses 2.4G wireless technology
In terms of product application, with the advantage that 2.4G technology can work duplex, the wireless headphones made by it can often integrate the microphone function (of course, with the fixed bandwidth occupied, the sound quality will decrease when the microphone is turned on). This provides great convenience for voice chat users. Coupled with the high confidentiality, power saving, and long transmission distance of 2.4G technology, we believe that this is the development trend of wireless headphones in the future.
Kleer is a communication technology based on 2.4G transmission frequency. Kleer technology's KLR3012 RF audio module can transmit data over a distance of more than 10 meters at 2.4Mbits/s through the 2.4GHz frequency band. Music files are high fidelity and lossless.
Because Kleer technology can meet the needs of lossless transmission, it is used more for high-end wireless headset products, such as Sennheiser's latest RS180 wireless headset and MX W1 wireless earbuds, both of which use Kleer Protocol. Through the actual test, it can be said that it is non-destructive performance.
Sennheiser RS180 headphones with Kleer technology
In addition, because the transmission protocol of Kleer technology is more mature, its distance between students is obviously much longer. For example, the Sennheiser RS180 wireless earphone we tested can work in an open area with a working range of up to 100 meters, which can fully meet the needs of villa-level rooms.
In terms of shortcomings, the price of products using Kleer technology is generally high. For example, we refer to the Sennheiser MX W1 or RS180, which are priced at 4,999 yuan and 3040 yuan respectively.
It is better to say that RF is more appropriate than RF technology. Here, we will quote Baidu Encyclopedia's interpretation of RF technology: "RF radio is radio frequency current, which is an abbreviation of high-frequency AC-changing electromagnetic wave. AC current changed less than 1000 times per second is called low-frequency current. More than 10,000 times is called high frequency current, and radio frequency is such a high frequency current. Radio frequency technology has a wide and irreplaceable role in the field of wireless communication."
Ear new wireless speaker
"The electrical information source (analog or digital) is modulated with high-frequency current (amplitude or frequency modulation) to form a radio frequency signal, which is transmitted into the air through the antenna; the radio frequency signal is received at a long distance and then inversely modulated to be restored into an electrical information source. This process is called wireless transmission. Wireless transmission has developed for nearly two hundred years and has formed a large number of users and product groups. However, due to climate change and the influence of surface obstacles, perfect information cannot be transmitted."
RF RF can't be said to be the latest technology, but it is also used in the wireless speaker products for the first time. He applied RF RF technology between the ear speaker and the transmitter, which not only solved the power supply problem of the speaker itself, but also solved the sound source of the speaker. In addition, RF RF technology has a wide frequency response range, which can also meet the lossless audio transmission, which is a space worth developing for manufacturers.
External wireless transmitter adopts RF technology
Conclusion <br> The above is the analysis of the advantages and disadvantages of the more common wireless transmission technology. It does not mean which modulation mode will become the mainstream or standard in the future. However, from the current trend, 2.4G is more favored by the headset manufacturers, and the characteristics of the speaker wireless products are not very obvious, we can not take this conclusion.
How far is the road to popularization? Analyze common wireless transmission technologies
Last year, the industry predicted that 2010 will be the wireless year of the domestic audio market. Major manufacturers, including speakers and headphones, are launching new products of their own wireless audio products. Through interviews with major audio vendors, we found that they also believe that wireless will gradually become popular in the future, and this ratio is likely to reach 70% or even higher. Not only that, they also believe that wireless is not equal to poor sound quality; instead, the sound quality of wireless products can be quite good.