DAB following the AM, FM broadcasting traditional analog broadcasting after the third generation - digital signal broadcasting, its appearance is a revolution in broadcasting technology. Digital broadcasting is immune to noise, interference, resistance to the decline of radio wave propagation, so the advantages for high-speed mobile reception. It provides CD-level quality stereo sound, the signal is almost zero distortion, to achieve "crystal clear" the fever-level broadcast quality, suitable for broadcast, "classical music", "Symphony", "popular music" and, most being professional musicians, music enthusiasts and audiophiles sought after! And in a certain range from multi-path interference effects, to ensure that fixed, portable and mobile reception of high quality.
Sensual simultaneously "listening" technology
According to the current popular saying, DAB is the era of audio transmission from analog to digital migration arising from the product of the times, it is also AM and FM after following the advent of third generation radio system. But even more interesting is that, relying on DAB, theoretically you can use the eyes to "listen" broadcast - because of the digital features, DAB can transmit signals of any text or even images. DAB radio so you can connect with the TV in order to restore the digital signal in the video image. In this sense, DAB has not a just a pure audio signal transmission system of the broadcast.
Even in radio quality, compared with analog radio, DAB radio also has a great advantage. DAB broadcast signal to noise ratio at least 95db or more coding rates reached more than 192Kbps, which has more than most of the MP3 sound quality standards. With digital signal transmission and because the disturbance and the characteristics of wave attenuation, DAB radio is very suitable for the mobile environment in the intense use, such as car.
The experience on the use, DAB radio and traditional AM / FM totally different. DAB radio only requires the user to remember a very limited number of bands can be - each band is a specific integrated radio, each station can also set up 5-6 in the frequency band channels. For a classical music lovers, listen to DAB radio typical steps are: transferred to the radio (such as BBC) where the "broadcast frequency", and then into their music under the sub-channel, and finally re-entering the classical music channel, as Open the menu the same.
In fact, DAB has become the United Kingdom and other Western European countries, digital audio broadcasting standard. At present, the greatest impact of a DAB standard is commonly known as "European regulations" of the Eureka-147, but its use is not confined to Europe. In addition, the United States developed IBOC (In-Band On-Channel) and France developed DRM (Digital Radio Mondiale) is the world's major technical standards for the two DAB. As a newly established last year in July the signing of DRM standards, the China has become the Union's 30 member. Through cooperation with the European Union, China has established a DAB laboratory in Beijing, and already started building in Guangdong pilot DAB DAB radio network and carried out.
Products increasingly rich, fully activate application
In fact, although the advent of DAB technology from nearly 25 years now, but it truly enter only the last 10 years of civil or even 5 years is something, DAB radio substantial price cuts as the 2003-2004 DAB radio in a rapid spread of these countries the most important factor.
DAB radio just launched in Foshan in 1996, China will buy only a Philips DAB radio to provide a model can only receive audio signals, the price is as high as £ 4,200. But since 2003, Britain's most expensive home and car DAB radio prices have fallen to 80 pounds, respectively, and 400 pounds. And Tsinghua University in China is also actively developing domestic-oriented affordable DAB radio.
So to speak, to listen to DAB radio's behavior has become a fashion, and to respond to more and more hardware vendors. In this year's CeBIT show, digital audio equipment maker iRiver introduced a model for the iDA-100's DAB radio. Although it supports MP3 and other popular audio file playback, but the battery is only a short period of seven hours, so iDA-100 is indeed to be a "play MP3 supplemented by radio." Also, with Creative sound card manufacturer TerraTec par has also entered the DAB field.
In China, apart from two in Guangdong and Beijing DAB applications take the first region, and Tianjin and Henan, have already launched a DAB application. The Philips also launched in China in August was able to receive DAB car radio broadcast.
DAB digital radio
Since 1920, Pittsburgh's KDKA radio station was formally launched, launched after the world's broadcasting history, with the advances in technology and the human pursuit of a higher quality of life, scientists are constantly studying how to improve broadcasting quality, improve service broadcasting quality. 80's, as the ever-changing digital technology, radio technology into a revolutionary era of digital broadcasting technology.
DAB digital radio is composed of 12 members of the Association - the famous EUREKA-147 being developed, the system is the name of the first digital audio broadcasting (DAB), and has been used to distinguish the real DAB radio and other audio broadcast standards . In 1994, Eureka-147 is the international standard used today, most of the world not to achieve this standard is being tested to this standard. There is disagreement only believe in satellite digital broadcasting and high definition broadcast of the United States and select a new transfer method of the Japanese broadcasting format. DAB system the world can be divided into the development of the EU regulation Eureka-147, U.S. IBOC (In-Band On-Channel) and the French DRM (Digital Radio Mondiale), DAB also part of the national self-development system, and our current pilot with Eureka-147 system.
Digital broadcasting is a single frequency modules. Can be transmitted through the multiplexed broadcast stereo or mono, but also send text and data. In the UK, the UK telecommunications industry associations in 217.5-230.0 MHz of spectrum allocated seven multiplexer. It allows a frequency of carrying more services, more efficient use of spectrum. The spectrum in the United Kingdom is called Band III. Some countries also use Band III for DAB radio, but more countries already use Band III for analog TV to send, the frequency from 1228MHz to 1575 Hz is called the L band DAB digital radio high frequency. These frequencies are also applied to broadcasting services by satellite. DAB digital radio in Germany to use Band III and L Band, and Canada use only the L Band. So if you buy a receiver in the UK, it can only receive DAB signals on Band III's can not work in other countries. In the future, the two band receiver can be used anywhere. In the United Kingdom, L Band now only applied to the point to point communication, but it is hoped to 2007 L Band frequencies can be applied to the DAB on.
The same as analog broadcasts, DAB digital radio transmission to go through a series of ground transmitters, so that national, regional, and local radio multiplex only be able to send to places designated by the State. This means the same as the analog broadcast, you can only play coverage areas where a signal is received. And satellite radio is different if you in Scotland, Wales, you will not receive the signal.
DAB in the navigation application
Using DAB technology as navigation systems can be broadcast to the same understanding of real-time traffic information, weather conditions, the elevated ramp of the open situation. Compared to previously used techniques of navigation in terms of TMC, DAB wider coverage area, listen to the signal and the sound quality is also superior. And thanks to the manner similar to radio, it will not produce traffic charges.
Media Group recently launched a series of little communication is to use DAB technology, as well as cinemas, information, and the future development of the road will speed function.
DAB in the electronic field of wide application in the future may also be developed for use in mobile phone technology.
Digital Audio Broadcasting (DAB) program development:
1. DAB BAND III
2. FM RDS
3. DAB and RDS automatic error correction
4. CLOCK / ALARM / SLEEP
5. Support the coding switch (Rotary encoder)
6. RF sensitivity is greater than-96dbu
7. IPOD DOCK
Contact: Mr. Huang Tel: 13554870869
About DAB receiver
Not all digital receivers are DAB receivers currently on the market, many of the digital receiver, but most of them made for the use of digital technology analog FM, AM radio and satellite radio receivers, such as digital receivers receiver. The DAB Eureka 147 receiver must meet the technical specifications in order to get DAB signal reception. ]
DAB radio services
1. Voice services (Audio service);
2. Packet Data Service (Packet Data Service);
3. Video (Video Streaming);
4. Dynamic label (Dynamic Label);
5. Presentation (Slide Shower);
6. Interactive Data (Interactive data service).
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Words Name: DAB
Chinese explanation: Digital Audio Broadcasting
Common alias: Digital Audio Broadcast
Abbreviations: DAB
Origin: Digital Audio Broadcasting
Overview DAB following the AM, FM broadcasting traditional analog broadcasting after the third generation, in addition to a digital signal transmission with noise, interference, anti-wave propagation fading ... so all the advantages, and provides CD quality stereo sound and digital information of services, and within a certain range from multi-path interference effects, to ensure that fixed, portable and mobile reception of high quality. DAB system the world can be divided into the development of the EU regulation Eureka-147, U.S. IBOC (In-Band On-Channel) and the French DRM (Digital Radio Mondiale), DAB also part of the national self-development system, and our current pilot with Eureka-147 system. Translated as Eureka 147 Eureka 147. The Eureka 147 standard background and technical details, visit [1]
】 【Eureka
Originally it was first composed of European countries, a technology research organization name of the cooperative groups, the technology group has been engaged in a variety of technology development projects. In the "Eureka" its vast technological development projects, DAB development project initialization, was listed as No. 147. Therefore, DAB project also used by people known as the "Eureka 147" program. Engaged in the project are from different countries broadcasting, network operators, electronic household appliances manufacturers and research institutions and so on. Through the joint efforts of all sides, "Eureka 147" plans to develop so far, has been formed and issued a full range of DAB technology standard that is being constantly updated and are accepted worldwide and application. The set of technical standards also known as the "Eureka 147" standard.
DAB frequencies to use,
Digital broadcasting is a single frequency modules. Can be transmitted through the multiplexed broadcast stereo or mono, but also send text and data. In the UK, the UK telecommunications industry associations in 217.5-230.0 MHz of spectrum allocated seven multiplexer. It allows a frequency of carrying more services, more efficient use of spectrum. The spectrum in the United Kingdom is called Band III.
Some countries also use Band III for DAB radio, but more countries already use Band III for analog TV to send, the frequency from 1228MHz to 1575 Hz is called the L band DAB digital radio high frequency. These frequencies are also applied to broadcasting services by satellite. DAB digital radio in Germany to use Band III and L Band, and Canada use only the L Band.
So if you buy a receiver in the UK, it can only receive DAB signals on Band III's can not work in other countries. In the future, the two band receiver can be used anywhere. In the United Kingdom, L Band now only applied to the point to point communication, but it is hoped to 2007 L Band frequencies can be applied to the DAB on.
DAB's development history
DAB technology stems from the Broadcasting Institute of Technology, Germany in 1980 to Eureka-147 system for terrestrial audio broadcasting technology research. 1985, and started in Munich, Germany DAB pilot experiment. In 1986, Germany, Britain, France and the Netherlands, Denmark and other countries of the Government and the broadcasters and the electronics industry Eureka Union were set, and to develop Eureka-147 DAB standard. DRM system proposed by the French in 1996, in 1998 in Guangzhou, China DRM Union officially launched in July 2003, currently about 30 Member States, the world has about 27 full operation of the DRM system, although China member of the Alliance for the DRM, but still the main DAB Eureka-147 standard test. IBOC systems for the U.S. plan based on Eureka-147's frequency while it is available, but I hope to master the development of digital broadcasting technology proposed, and the use of existing AM and FM bands as IBOC R & D work, because of sound quality situation had not improved, the current reform IBOC HDC codec used in research and development test
DAB features
DAB uses advanced digital technology ─ orthogonal frequency division multi-task technique (OFDM), can be very low data transmission rate and lower distortion of stereo CD quality programs, in addition to solve the traditional analog broadcast reception and interference problems bad, better further providing barrier-free reception of data services. To Eureka-147, for example, the frequency bandwidth demand for video content cut into multiple compressed audio signal and additional data, data, through multi-tasking, and then through the OFDM (Orthogonal Frequency Division Multiplexing) modulation can be 1.5MHz within the transmission bandwidth. Eureka-147's biggest features is the use of guard band (Guardband) and staggered code (Interleave) method, to avoid multi-path and Doppler effects caused by selective fading and ISI (Intersymbol Interference), uses only one frequency cover the whole region could be achieved, that is, the so-called single frequency network (Single Frequency Network; SFN), which use multiple channels simultaneously broadcast on the same launch the same program, to cover the purpose of the whole region, but will not produce the same frequency interference.
Differences between DAB and traditional radio
DAB and traditional radio (FM, AM) The biggest difference, in addition to DAB with CD sound quality of the transmission quality and technologies, DAB also has the reception of multimedia information, including text, data, pictures, images, and even real-time information updates. Therefore, the application of DAB, and not limited to audio transmission (Audio Broadcast) services, more importantly, data video services (Data Broadcasting) service, many scholars and experts will be called DAB Digital Broadcasting.
The status and development of DAB
Britain is currently the DAB should be the fastest growing countries, the UK there are about 300 national or local radio stations to provide digital programming and information services covering 80% of the UK. Germany has more than 150 radio stations to provide DAB service, service area covers about 70% in Germany. Taiwan has a total of eight experimental system frequency broadcast signals by the PRT, the Asian radio station, National Taichung, Kaohsiung, a coalition of public radio stations ... and so is superior messaging company, made in northern, central, and southern areas of the 10C-band experimental license Taiwan is fully committed to promote the popularization and application of DAB efforts.
DAB shows how to receive
DAB DAB receiver program must use a dedicated receiving device can listen to or watch get what you want to receive the program or information. DAB receivers can be divided into vehicle type, household type, portable type and the computer to receive cards, a move to use, vehicle and portable type of DAB receiving equipment generally and the current FM / AM receiver functions similar, in addition to FM / AM's basic functions, other Qixiang Ruo by the? AB features, but limited to the programs to receive Audio, while the receiving device on the LCD screen will display multiple channels to receive the basic message; computer DAB receiving equipment to receive the card, in addition to receiving general Audio programs, the other can also receive text, pictures, video .. etc, as installed on the computer, and then through the integration of the Internet, application level, the more extensive and flexible; currently more expensive type of motor and portable DAB receiver to receive also have the computer equipment to receive cards can achieve most of the functionality.
Antenna
Because the analog and DAB are two completely different radio technology, so a FM antenna for the digital broadcast receiver can not work. Even if you are in the steel frame of the building or in the basement, indoor antenna digital receiver can work perfectly. A rule of thumb method, if your FM or mobile phone reception is poor, you will fail the indoor antenna to receive DAB. If this is the case, you need an antenna installed on the roof. For best results, double-dipole or Yagi antenna must point to the direction of the transmitter. DAB antenna to vertical polarization.
Biology DAB
Biology, DAB (Diaminobenzidine), diaminobenzidine is the most sensitive horseradish peroxidase, the most commonly used chromogenic substrates, reaction products because they did not dissolve in water, xylene and alcohol brown sediments are widely for Western blot (Western Blot, WB), immunohistochemistry (Immunohistochemistry, IHC) and immunocytochemistry (Immunocytochemistry, ICC), dot blot (Dot blot), and biological chips (Biochip) and other dyes and color reaction.
Its structure is as follow:
Notes
1. DAB solution should be stored at low temperature sealing. If crystallization, should ensure further use of crystal is completely dissolved;
2. Color working solution should be used and are equipped, freshly prepared working solution should be colorless or light brown, if dark, do not use;
3. DAB unstable at room temperature, after each access shall be stamped with seals back into the refrigerator promptly to avoid decomposition due to effects DAB test, or test leakage caused environmental pollution;
4. DAB has the potential mutagenic effects, the operation should pay attention to Wear protective equipment.
