In-band on-channel
Encyclopedia
In-band on-channel is a hybrid method of transmitting digital radio
and analog radio broadcast
signals simultaneously
on the same frequency
.
By utilizing additional digital subcarrier
s or sideband
s, digital
information is "multiplexed
" on an AM
or FM
analog signal, thus avoiding re-allocation
of the broadcast bands. However, by putting RF
energy outside of the normally-defined
channel
, interference
to adjacent channel
stations is increased when using digital sidebands.
IBOC does allow for multiple program channels, though this can entail taking some existing subcarriers off the air to make additional bandwidth available in the modulation baseband
. On FM, this could eventually mean removing stereo
. On AM, IBOC is incompatible with analog stereo, and any additional channels are limited to highly-compressed voice, such as traffic
and weather
. Eventually, stations can go from hybrid
mode (both analog and digital) to all-digital, by eliminating the baseband monophonic
audio.
.
in the United States, is the proprietary HD Radio
system developed by iBiquity
Digital Corporation, which transmits energy beyond the alloted ±100 kHz FM channel. This creates potential interference issues with adjacent channels. This is the most widespread system in use, with approximately 1,556 stations transmitting HD radio in the US, plus over 800 new multicast channels (as of Jan 2010). There is a one-time license fee to iBiquity Digital, for the use of its intellectual property, as well as costs for new equipment which range from $50,000 to $100,000 US (2010) per station.
by Digital Radio Express, which instead uses subcarriers within the existing signal. This system was introduced more recently. The system is compatible with HD Radio in hybrid mode, but not in all-digital mode, and with RBDS. The stereo subcarrier can be removed to make more space available for FMeXtra in the modulation baseband. However, the system is not compatible with other existing 67–92 kHz subcarriers which have mostly fallen into disuse. The system is far less expensive and less complicated to implement, needing only to be plugged in to the existing exciter, and requiring no licensing fees. FMeXtra has generally all the user features of HD Radio, including multicast capability; the ability to broadcast several different audio programs simultaneously. It uses the aacPlus (HE-AAC) codec.
FMeXtra can control listening with conditional access
and encryption
.
allows for simultaneous transmission of multiple data streams alongside an audio signal. The DRM+ standard provides bandwidths from between 35 kbit/s to 185 kbit/s and up to four simultaneous data streams, allowing near-CD quality audio to be broadcast alongside other multimedia content - images, video or HTML content are typical examples.
DRM+ is a superset of the original DRM standard, allowing for broadcasts at frequencies of up to 174 MHz (whereas DRM only operates at up to 30 MHz). While it is not backwardly compatible with existing FM receiver equipment, with broadcasts digitally encoded using AAC, this ability to operate within the internationally agreed FM spectrum of 88-108 MHz makes DRM+ a viable candidate for future adoption when countries begin to switch off their analogue broadcasts.
HD Radio system for AM, which is the only system approved by the Federal Communications Commission for digital AM broadcasting in the United States. The HD Radio system employs use of injected digital sidebands above and below the audible portion of the analog audio on the primary carrier. This system also phase modulates the carrier in quadrature
and injects more digital information on this phase-modulated portion of the carrier. It is based on the principle of AM stereo
where it puts a digital signal where the C-QUAM
system would put the analog stereo decoding information.
HD Radio system, although it requires new frequency. It is the only one to have been accepted mediumwave but also shortwave
(and possibly longwave
) by the International Telecommunication Union
(ITU) for use in regions I and III, but not yet in region II, the Americas
. The HD Radio system has also been approved by International Telecommunication Union.
is yet another method, though it is more of an extension of the current system. Developed by AM stereo pioneer Leonard Kahn, It encodes the treble on very small digital sidebands which do not cause interference to adjacent channels, and mixes it back with the analog baseband. Unlike the other two, it is not intended to be capable of multichannel, opting for quality over quantity. Unlike the HD system iBiquity calls "hybrid digital" the CAM-D system truly is a direct hybrid of both analog and digital. Some engineers believe that CAM-D may be compatible with analog AM stereo with the right engineering.
Critics of CAM-D point to several drawbacks:
There was also concern that AM and FM stations' branding, using their current frequencies, would be lost to new channel numbers, though virtual channels such as on digital television would eliminate this. Also, several competing stations would have to share a transmitter that multiplexes them all into one ensemble with the same coverage area (though many FM stations are already diplexed in large cities such as New York). http://www.esbnyc.com/tourism/tourism_facts_broadcasting.cfm A further concern to FM stations was that AM stations could suddenly be in competition with the same high audio quality, although FM would still have the advantage of higher data rates (300 kbit/s versus 60 kbit/s in the HD Radio standard) due to greater bandwidth (100 kHz versus 10 kHz).
The most significant advantage for IBOC is its relative ease of implementation. Existing analog radios are not rendered obsolete and the consumer and industry may transition to digital at a rational pace. In addition, the technology infrastructure is in place: most major broadcast equipment manufacturers are implementing IBOC technology and 60+ receiver manufacturers are selling IBOC reception devices. In the UK, Denmark, Norway and Switzerland, which are the leading countries with regard to implementing DAB, the first-generation MPEG-1 Audio Layer II
(MP2) codec stereo radio stations on DAB have a lower sound-quality than FM, prompting a number of complaints. The typical bandwidth for DAB programs is only 128 kbit/s using the first generation CODEC, less-robust MP2 standard which requires at least double that rate to be considered near-CD quality.
Other issues with DAB include "downgrading" stations from stereo to monaural
, in order to squeeze even more channels into the limited 1000 kbit/s bandwidth, smaller coverage of markets as compared to analog FM, radios that are overly expensive, poor reception inside vehicles or buildings, and a general lack of interest in DAB (only 5 million units sold in the largest take up area of UK by mid-2007).
A new version of the Eureka-147 standard called DAB+ has been implemented. Using the more efficient high quality MPEG-4 CODEC called HE-AAC v2, this compression method will allow the DAB+ system to carry more channels or have better sound quality at the same bit rate as the old DAB system. It is the new DAB+ implementation which will be under consideration for new station designs and not the earlier DAB scheme using the MUSICAM CODEC. This new DAB+ system was coordinated and developed by the World DAB Forum, formed in 1997 from the old organization. It will give the Eureka-147 system a similar quality per bit rate as the IBOC system and hence a better sound quality than FM.
Both AM and FM IBOC signals cause interference to adjacent-channel stations, but not within the station’s interference-free protected contours designated by the U.S. Federal Communications Commission
(FCC). It has led to derogatory terms such as IBAC (In-band adjacent-channel) and IBUZ (since the interference sounds like a buzz.) The range of a station on an HD Radio receiver is somewhat less than its analog signal. However, in June, 2008, a group of US broadcasters and equipment manufacturers requested that the U.S. FCC increase the permissible FM IBOC power from 1% (currently) to a maximum of 10% of the analog power. On January 29, 2010, the FCC approved the request. In addition, tropospheric ducting and e-skip can reduce the range of the digital signal, as well as the analog.
In-band on-channel digital radios using iBiquity's standard are being marketed under the brand "HD Radio" to highlight the purported quality of reception. As of June 2008, over 60 different receiver models have been made, and stations have received blanket (no longer individual and experimental) authorization from the U.S. FCC to transmit in a multiplexed multichannel mode on FM. Originally, the use of HD Radio transmission on AM was limited to daytime only, and not allowed at night due to potential problems with skywave radio propagation. The FCC lifted this restriction in early 2007. DRM, however, is being used across Europe on shortwave, which is entirely AM skywave, without issue. With the proper receiver, many of those stations can be heard in North America as well, sans the analog signal.
(CBC) have also looked at the use of HD Radio, given its gradual progress in the neighbouring U.S. The CBC began HD Radio testing in September 2006, focusing on transmissions from Toronto
and Peterborough, Ontario
. The CRTC has since revised its policy on digital radio to allow HD Radio operations pursuant to Public Notice CRTC 2006-160.
are allowed to transmit their programs on the AM and FM bands utilizing HD Radio technology. Approximately six Mexican AM and FM stations are already operating with HD Radio technology along Mexico’s border area with the US. Groupo Imagen commenced HD Radio transmissions on XHDL and XEDA in Mexico City in June 2008.
As of May 2007, FMeXtra is on several dozen stations. Several hundred stations belonging to the Idea Bank consortium
will also have FMeXtra installed. http://www.dreinc.com/company/pr/4_14_06.html
Digital radio
Digital radio has several meanings:1. Today the most common meaning is digital radio broadcasting technologies, such as the digital audio broadcasting system, also known as Eureka 147. In these systems, the analog audio signal is digitized into zeros and ones, compressed using formats such as...
and analog radio broadcast
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
signals simultaneously
Simulcast
Simulcast, shorthand for "simultaneous broadcast", refers to programs or events broadcast across more than one medium, or more than one service on the same medium, at the same time. For example, Absolute Radio is simulcast on both AM and on satellite radio, and the BBC's Prom concerts are often...
on the same frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
.
By utilizing additional digital subcarrier
Subcarrier
A subcarrier is a separate analog or digital signal carried on a main radio transmission, which carries extra information such as voice or data. More technically, it is an already-modulated signal, which is then modulated into another signal of higher frequency and bandwidth...
s or sideband
Sideband
In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, containing power as a result of the modulation process. The sidebands consist of all the Fourier components of the modulated signal except the carrier...
s, digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
information is "multiplexed
Multiplexing
The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...
" on an AM
Amplitude modulation
Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...
or FM
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...
analog signal, thus avoiding re-allocation
Frequency allocation
Use of radio frequency bands of the electromagnetic spectrum is regulated by governments in most countries, in a Spectrum management process known as frequency allocation or spectrum allocation. Radio propagation does not stop at national boundaries...
of the broadcast bands. However, by putting RF
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
energy outside of the normally-defined
Spectral mask
In telecommunications, a spectral mask, also known as a channel mask or transmission mask, is a mathematically-defined set of lines applied to the levels of radio transmissions. The spectral mask is generally intended to reduce adjacent-channel interference by limiting excessive radiation at...
channel
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...
, interference
Adjacent-channel interference
Adjacent-channel interference is interference caused by extraneous power from a signal in an adjacent channel. ACI may be caused by inadequate filtering , improper tuning or poor frequency control .ACI is distinguished from crosstalk.Broadcast...
to adjacent channel
Adjacent channel
In broadcasting an adjacent channel is an AM, FM, or TV channel that is next to another channel. First-adjacent is immediately next to another channel, second-adjacent is two channels away, and so forth. Information on adjacent channels is used in keeping stations from interfering with one...
stations is increased when using digital sidebands.
IBOC does allow for multiple program channels, though this can entail taking some existing subcarriers off the air to make additional bandwidth available in the modulation baseband
Baseband
In telecommunications and signal processing, baseband is an adjective that describes signals and systems whose range of frequencies is measured from close to 0 hertz to a cut-off frequency, a maximum bandwidth or highest signal frequency; it is sometimes used as a noun for a band of frequencies...
. On FM, this could eventually mean removing stereo
Stereophonic sound
The term Stereophonic, commonly called stereo, sound refers to any method of sound reproduction in which an attempt is made to create an illusion of directionality and audible perspective...
. On AM, IBOC is incompatible with analog stereo, and any additional channels are limited to highly-compressed voice, such as traffic
Traffic
Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel...
and weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
. Eventually, stations can go from hybrid
HD Radio
HD Radio, which originally stood for "Hybrid Digital", is the trademark for iBiquity's in-band on-channel digital radio technology used by AM and FM radio stations to transmit audio and data via a digital signal in conjunction with their analog signals...
mode (both analog and digital) to all-digital, by eliminating the baseband monophonic
Monaural
Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...
audio.
FM methods
On FM there are currently three methods of IBOC broadcasting in use, mainly in the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
HD Radio Broadcasting
The first, and currently only, digital technology approved for use on AM and FM broadcast frequencies by the Federal Communications CommissionFederal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
in the United States, is the proprietary HD Radio
HD Radio
HD Radio, which originally stood for "Hybrid Digital", is the trademark for iBiquity's in-band on-channel digital radio technology used by AM and FM radio stations to transmit audio and data via a digital signal in conjunction with their analog signals...
system developed by iBiquity
IBiquity
iBiquity Digital Corporation is a company formed by the merger of USA Digital Radio and Lucent Digital Radio, with the goal of creating an in-band on-channel digital radio system for the United States and around the world...
Digital Corporation, which transmits energy beyond the alloted ±100 kHz FM channel. This creates potential interference issues with adjacent channels. This is the most widespread system in use, with approximately 1,556 stations transmitting HD radio in the US, plus over 800 new multicast channels (as of Jan 2010). There is a one-time license fee to iBiquity Digital, for the use of its intellectual property, as well as costs for new equipment which range from $50,000 to $100,000 US (2010) per station.
FMeXtra
The other system is FMeXtraFMeXtra
FMeXtra, now marketed as VuCast and oriented at the broadcast data market like MSN Direct, is an in-band on-channel digital radio broadcasting technology created by Digital Radio Express, now VuCast Media. Unlike iBiquity's HD Radio system, it uses any FM radio station's existing equipment and...
by Digital Radio Express, which instead uses subcarriers within the existing signal. This system was introduced more recently. The system is compatible with HD Radio in hybrid mode, but not in all-digital mode, and with RBDS. The stereo subcarrier can be removed to make more space available for FMeXtra in the modulation baseband. However, the system is not compatible with other existing 67–92 kHz subcarriers which have mostly fallen into disuse. The system is far less expensive and less complicated to implement, needing only to be plugged in to the existing exciter, and requiring no licensing fees. FMeXtra has generally all the user features of HD Radio, including multicast capability; the ability to broadcast several different audio programs simultaneously. It uses the aacPlus (HE-AAC) codec.
FMeXtra can control listening with conditional access
Conditional access
Conditional Access is the protection of content by requiring certain criteria to be met before granting access to this content...
and encryption
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
.
DRM+
Digital Radio MondialeDigital Radio Mondiale
Digital Radio Mondiale is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly shortwave...
allows for simultaneous transmission of multiple data streams alongside an audio signal. The DRM+ standard provides bandwidths from between 35 kbit/s to 185 kbit/s and up to four simultaneous data streams, allowing near-CD quality audio to be broadcast alongside other multimedia content - images, video or HTML content are typical examples.
DRM+ is a superset of the original DRM standard, allowing for broadcasts at frequencies of up to 174 MHz (whereas DRM only operates at up to 30 MHz). While it is not backwardly compatible with existing FM receiver equipment, with broadcasts digitally encoded using AAC, this ability to operate within the internationally agreed FM spectrum of 88-108 MHz makes DRM+ a viable candidate for future adoption when countries begin to switch off their analogue broadcasts.
HD Radio Broadcasting
iBiquity also created a mediumwaveMediumwave
Medium wave is the part of the medium frequency radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz...
HD Radio system for AM, which is the only system approved by the Federal Communications Commission for digital AM broadcasting in the United States. The HD Radio system employs use of injected digital sidebands above and below the audible portion of the analog audio on the primary carrier. This system also phase modulates the carrier in quadrature
Quadrature
Quadrature may refer to:In signal processing:*Quadrature amplitude modulation , a modulation method of using both an carrier wave and a 'quadrature' carrier wave that is 90° out of phase with the main, or in-phase, carrier...
and injects more digital information on this phase-modulated portion of the carrier. It is based on the principle of AM stereo
AM stereo
AM stereo is a term given to a series of mutually incompatible techniques for wireless radio broadcasting stereo audio in the AM band in a manner that is compatible with standard AM receivers...
where it puts a digital signal where the C-QUAM
C-QUAM
C-QUAM is the method of AM stereo broadcasting used in Canada, the United States and most other countries. It was invented in 1977 by Norman Parker, Francis Hilbert, and Yoshio Sakaie, and published in an IEEE journal....
system would put the analog stereo decoding information.
DRM
Digital Radio Mondiale has had much more success in creating an AM system, and one that could be much less expensive to implement than any proprietaryProprietary protocol
In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual.-Enforcement:Proprietors may enforce restrictions through patents and by keeping the protocol specification a trade secret...
HD Radio system, although it requires new frequency. It is the only one to have been accepted mediumwave but also shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
(and possibly longwave
Longwave
In radio, longwave refers to parts of radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths...
) by the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
(ITU) for use in regions I and III, but not yet in region II, the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
. The HD Radio system has also been approved by International Telecommunication Union.
CAM-D
CAM-DCAM-D
Compatible Amplitude Modulation - Digital or CAM-D is a proposed hybrid digital radio format for AM broadcasting, put forth by well-known broadcast engineer Leonard R. Kahn....
is yet another method, though it is more of an extension of the current system. Developed by AM stereo pioneer Leonard Kahn, It encodes the treble on very small digital sidebands which do not cause interference to adjacent channels, and mixes it back with the analog baseband. Unlike the other two, it is not intended to be capable of multichannel, opting for quality over quantity. Unlike the HD system iBiquity calls "hybrid digital" the CAM-D system truly is a direct hybrid of both analog and digital. Some engineers believe that CAM-D may be compatible with analog AM stereo with the right engineering.
Critics of CAM-D point to several drawbacks:
- being primarily analog, the system will be just as subject to artificial interference and noise as the current AM system
- there are virtually no receivers available for the system and at present, no major manufacturer has announced even the intention to begin production of them; and
- the cost of retrofitting with CAM-D is more than that of simply buying a new, HD-ready solid state transmitter.
IBOC Versus DAB
While the United Kingdom has chosen the Eureka 147 standard of digital audio broadcasting (DAB) for creating a digital radio service, the United States has selected IBOC technology for its digital AM and FM stations. The band used for terrestrial DAB in the UK is VHF band III, which does not suffer from L-band's significant line-of-sight problems. However, it is not available in North America since that span is occupied by TV channels 7 to 13. The stations currently occupying that spectrum did not wish to give up their space, since VHF offers several benefits over UHF: relatively lower power, long distance propagation (up to 100 miles (160 km) with a rooftop antenna), and a longer wavelength that is more robust and less affected by interference. In Canada, the Canadian Radio-television and Telecommunications Commission (CRTC) is continuing to follow the analog standard, so the channels remain unavailable there as well. HD Radio testing has been authorized in Canada, as well as other countries around the world.There was also concern that AM and FM stations' branding, using their current frequencies, would be lost to new channel numbers, though virtual channels such as on digital television would eliminate this. Also, several competing stations would have to share a transmitter that multiplexes them all into one ensemble with the same coverage area (though many FM stations are already diplexed in large cities such as New York). http://www.esbnyc.com/tourism/tourism_facts_broadcasting.cfm A further concern to FM stations was that AM stations could suddenly be in competition with the same high audio quality, although FM would still have the advantage of higher data rates (300 kbit/s versus 60 kbit/s in the HD Radio standard) due to greater bandwidth (100 kHz versus 10 kHz).
The most significant advantage for IBOC is its relative ease of implementation. Existing analog radios are not rendered obsolete and the consumer and industry may transition to digital at a rational pace. In addition, the technology infrastructure is in place: most major broadcast equipment manufacturers are implementing IBOC technology and 60+ receiver manufacturers are selling IBOC reception devices. In the UK, Denmark, Norway and Switzerland, which are the leading countries with regard to implementing DAB, the first-generation MPEG-1 Audio Layer II
MPEG-1 Audio Layer II
MPEG-1 Audio Layer II or MPEG-2 Audio Layer II is a lossy audio compression format defined by ISO/IEC 11172-3 alongside MPEG-1 Audio Layer I and MPEG-1 Audio Layer III...
(MP2) codec stereo radio stations on DAB have a lower sound-quality than FM, prompting a number of complaints. The typical bandwidth for DAB programs is only 128 kbit/s using the first generation CODEC, less-robust MP2 standard which requires at least double that rate to be considered near-CD quality.
Other issues with DAB include "downgrading" stations from stereo to monaural
Monaural
Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...
, in order to squeeze even more channels into the limited 1000 kbit/s bandwidth, smaller coverage of markets as compared to analog FM, radios that are overly expensive, poor reception inside vehicles or buildings, and a general lack of interest in DAB (only 5 million units sold in the largest take up area of UK by mid-2007).
A new version of the Eureka-147 standard called DAB+ has been implemented. Using the more efficient high quality MPEG-4 CODEC called HE-AAC v2, this compression method will allow the DAB+ system to carry more channels or have better sound quality at the same bit rate as the old DAB system. It is the new DAB+ implementation which will be under consideration for new station designs and not the earlier DAB scheme using the MUSICAM CODEC. This new DAB+ system was coordinated and developed by the World DAB Forum, formed in 1997 from the old organization. It will give the Eureka-147 system a similar quality per bit rate as the IBOC system and hence a better sound quality than FM.
Challenges
AM IBOC in the United States still faces some serious technological challenges of its own, including nighttime interference with other stations. iBiquity was previously using PAC (also used at a higher bitrate in Sirius satellite radio [see Digital Audio Radio Service ]), but in August 2003 a switch to HDC (based-upon ACC) was made to rectify these problems. HDC has been customized for IBOC, and it is also likely that the patent rights and royalties for every transmitter and receiver can be retained longer by creating a more proprietary system. Digital Radio Mondiale is also developing an IBOC system, likely to be used worldwide with AM shortwave radio, and possibly with broadcast AM and FM. Neither of those have been approved yet for ITU region 2 (the Americas). The system, however, unlike HD Radio, does not permit the existing analog signal and the digital signal to live together in the same channel. DRM requires an additional channel to maintain both signals.Both AM and FM IBOC signals cause interference to adjacent-channel stations, but not within the station’s interference-free protected contours designated by the U.S. Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC). It has led to derogatory terms such as IBAC (In-band adjacent-channel) and IBUZ (since the interference sounds like a buzz.) The range of a station on an HD Radio receiver is somewhat less than its analog signal. However, in June, 2008, a group of US broadcasters and equipment manufacturers requested that the U.S. FCC increase the permissible FM IBOC power from 1% (currently) to a maximum of 10% of the analog power. On January 29, 2010, the FCC approved the request. In addition, tropospheric ducting and e-skip can reduce the range of the digital signal, as well as the analog.
In-band on-channel digital radios using iBiquity's standard are being marketed under the brand "HD Radio" to highlight the purported quality of reception. As of June 2008, over 60 different receiver models have been made, and stations have received blanket (no longer individual and experimental) authorization from the U.S. FCC to transmit in a multiplexed multichannel mode on FM. Originally, the use of HD Radio transmission on AM was limited to daytime only, and not allowed at night due to potential problems with skywave radio propagation. The FCC lifted this restriction in early 2007. DRM, however, is being used across Europe on shortwave, which is entirely AM skywave, without issue. With the proper receiver, many of those stations can be heard in North America as well, sans the analog signal.
Argentina
HD Radio technology was tested in 2004 with initial trials in Buenos Aires. Further testing of the technology began in early 2007.Brazil
HD Radio transmission in Brazil was started on September 26, 2005. The radio stations that use IBOC HD in Brazil are Radio Bandeirantes, Radio Globo, and RBS Group. A total of six stations – one FM and one AM from each group – are now transmitting in HD Radio. KISS FM in São Paulo is the first HD Radio station in Brazil. A total of 24 stations are broadcasting in Brazil as of June, 2008. A joint study by the government (ANATEL) and broadcasters’ associations (ABERT, AESP) is under construcion, but the results are not completed until this moment (19th september 2011).Canada
After having L-band DAB for several years, the Canadian Radio-Television and Telecommunications Commission (CRTC) and Canadian Broadcasting CorporationCanadian Broadcasting Corporation
The Canadian Broadcasting Corporation, commonly known as CBC and officially as CBC/Radio-Canada, is a Canadian crown corporation that serves as the national public radio and television broadcaster...
(CBC) have also looked at the use of HD Radio, given its gradual progress in the neighbouring U.S. The CBC began HD Radio testing in September 2006, focusing on transmissions from Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
and Peterborough, Ontario
Peterborough, Ontario
Peterborough is a city on the Otonabee River in southern Ontario, Canada, 125 kilometres northeast of Toronto. The population of the City of Peterborough was 74,898 as of the 2006 census, while the census metropolitan area has a population of 121,428 as of a 2009 estimate. It presently ranks...
. The CRTC has since revised its policy on digital radio to allow HD Radio operations pursuant to Public Notice CRTC 2006-160.
China
In China, Hunan Broadcasting Company started FMeXtra transmissions in Changsha in April 2007, and plans to put others throughout the Hunan province. [1] SARFT (State Administration for Radio, Film and Television) is currently testing HD Radio in Beijing in contemplation for acceptance in that country.Colombia
Caracol Radio began testing of the HD Radio technology in both the AM and FM bands in early 2008.El Salvador
El Salvador will be choosing HD Radio as its digital radio standard.Europe
In September 2007 the European HD Radio Alliance (EHDRA) was formed by broadcasters and other interested groups to promote the adoption of HD Radio technology by European broadcasters, regulators and standards organizations.France
France began broadcasting an HD Radio signal in March 2006 and plans to multicast two or more channels. The radio stations that use IBOC HD in France are SIRTI and NRJ Group. The owner of the transmitter is Towercast. The frequency of IBOC HD radio is 88.2 MHz. In May 2006, The Towercast group added a single channel of digital audio on 93.9 MHz.Germany
Radio Regenbogen began HD Radio operations on 102.8 MHz in Heidelberg on December 3, 2007 pursuant to government testing authority.Indonesia
Forum Radio Jaringan Indonesia had tested IBOC HD transmission from March 2006 to May 2006. The IBOC HD station in Jakarta was Delta FM (99.1 MHz). In April 2006, Radio Sangkakala (in Surabaya), the first AM HD radio station in Asia, went on the air on 1062 kHz.Jamaica
Radio Jamaica began operating full time with both HD Radio AM and FM signals in the city of Kingston in 2008.Mexico
All Mexican radio stations within 320 km of the U.S. borderBorder blaster
A border blaster is a licensed commercial radio station that transmits at very high power from one nation to another. Border blasters should not be confused with international broadcast stations...
are allowed to transmit their programs on the AM and FM bands utilizing HD Radio technology. Approximately six Mexican AM and FM stations are already operating with HD Radio technology along Mexico’s border area with the US. Groupo Imagen commenced HD Radio transmissions on XHDL and XEDA in Mexico City in June 2008.
New Zealand
HD Radio transmission in Auckland, New Zealand was started on October 19, 2005. The frequency of IBOC HD radio is 106.1 MHz. The transmitter is located at Skytower. Following successful testing, the Radio Broadcasters Association (RBA) initiated a comprehensive trial of HD Radio technology in December 2006. The aim of the trial was to assess the coverage potential of the HD Radio system and to make a recommendation on the suitability of the technology for adoption.Philippines
The first HD Radio station in the Philippines began broadcasting on November 9, 2005. The Philippines National Telecommunications Commission finalized its rules for FM digital radio operations on November 11, 2007.Poland
An HD Radio trial began in Warsaw in 2006 in order to demonstrate the technology to local radio stations.Puerto Rico
WPRM FM is the first station in San Juan, Puerto Rico (part of the US) to adopt HD Radio, in April 2005. WRTU in San Juan has also commenced broadcasting in HD Radio technology in 2007.Switzerland
FM testing sponsored by Radio Sunshine and Ruoss AG began in Lucerne in April 2006. HD Radio operations in Switzerland continue and are spotlighted each year during “HD Radio Days”, an annual gathering in Lucerne of European broadcasters and manufacturers for the purpose of discussing the rollout of the technology in Europe.Thailand
HD Radio transmission in Thailand was started in April 2006. Radio of Thailand had created a public IBOC HD radio network targeting mass transit commuters in Thailand's capital of Bangkok. To receive the broadcasts, more than 10,000 HD Radio receivers were installed in buses.Ukraine
The first FM HD Radio broadcasts in Kiev went on the air in October 2006 on two FM stations operated by the First Ukrainian Radio Group.Vietnam
Voice of Vietnam (VOV) commenced AM and FM HD Radio transmissions in Hanoi in June, 2008 including multicasting, in anticipation of making HD Radio technology a standard.United States
As of June 2008, more than 1,700 HD Radio stations were broadcasting 2,432 HD Radio channels. HD Radio technology is the only digital technology approved by the FCC for digital AM and FM broadcasting in the US. Over 60 different HD Radio receivers are on sale in over 12,000 stores nationwide, including Apple, Best Buy, Target, and Wal-Mart.As of May 2007, FMeXtra is on several dozen stations. Several hundred stations belonging to the Idea Bank consortium
Consortium
A consortium is an association of two or more individuals, companies, organizations or governments with the objective of participating in a common activity or pooling their resources for achieving a common goal....
will also have FMeXtra installed. http://www.dreinc.com/company/pr/4_14_06.html
See also
- Digital Audio BroadcastingDigital audio broadcastingDigital Audio Broadcasting is a digital radio technology for broadcasting radio stations, used in several countries, particularly in Europe. As of 2006, approximately 1,000 stations worldwide broadcast in the DAB format....
- Digital Audio Radio ServiceDigital Audio Radio ServiceDigital Audio Radio Service or DARS refers to any type of digital radio service. In the United States it is the official FCC term for digital radio services....
- Digital Radio MondialeDigital Radio MondialeDigital Radio Mondiale is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly shortwave...
- IBACIbacIbac is a fictional Fawcett Comics and DC Comics supervillain, and a foe of Captain Marvel. Created by writer Otto Binder and artist C.C. Beck, he first appeared in Captain Marvel Adventurs #8 .-Fictional character biography:...
- ISDBISDBIntegrated Services Digital Broadcasting is a Japanese standard for digital television and digital radio used by the country's radio and television stations. ISDB replaced the previously used MUSE "Hi-vision" analogue HDTV system...