IBOC

IBOC the Technology
IBOC stands for In-Band-On-Channel , which is a generic term for a way of getting from analogue to digital without an interruption in service. The solution being deployed in the USA is the one from the iBiquity Digital Corporation. The simultaneous broadcasting of both the analogue and digital components in called the IBOC Hybrid mode and is analogous to DRM’s Simulcast system. IBOC can be applied to both AM ( medium wave) and FM (VHF) bands .and of course has a purely digital mode as well once the changeover has been completed.
Just as DRM is getting a lot of criticism so it seems that IBOC system in the USA is not everybody’s cup of tea. The main complaint is that the current system is causing too much interference to existing analogue services.

IBOC in Europe
IBOC has caught the imagination of some radio stations in Europe and a long term test is being carried out on the VHF-FM band in the Swiss valleys. This is a mutually beneficial test as the Europeans get to test the IBOC technology and the inventors can create and test a Single Frequency Network (SFN) using the IBOC, a thing that haven’t be able to achieve in the USA. More

IBOC Worldwide
Brazil has at least four stations testing on both AM and FM; other countries have carried out brief tests during major conferences. Canada is the latest country to consider the technology, which makes sense given its proximity to the USA.

Compatible AM Digital

Somewhat out of the blue a new contender has appeared on the scene. This rival idea is from Leonard Kahn, who may be known to some as an engineer who was heavily involved in promoting an alternative to the AM stereo system called C-QUAM. I believe that Kahn’s system was promoted under his name. The rival IBOC system is called CAM-D^TM, Compatible AM Digital. Technical details are sketchy and the system is supposed to be based on existing patents.

 Mr. Kahn steadfastly refuses to issue any technical details. It is possible that the system is making use of independent analogue sidebands for the audio and that the audio may be band-limited to around 8 KHz. The portion above 8 KHz then carries the digital signal. This is just speculation at the moment. Leonard Kahn claims that his system does not cause interference to existing services. Three stations are now trialling the system. At the beginning of March 2005 Leonard Kahn threw down the gauntlet by claiming that the current IBOC system actually violates FCC interference rules and that station operators are afraid to operate ‘after midnight’ as the true level of interference will then be experienced.

The challenge has been issued to iBiquity, Viacom, Clear Channel and Susquehanna Radio.