[BC] Bitrates

[Craig Bowman]

Both AM and FM Ibiquity systems place the digital carrier fully in the 
adjacent channel.  It "fits within the mask" is the excuse people use to 
call it IBOC but the (FM) mask was developed for this purpose to allow 
such encroachment.  Both systems are IBAC plain and simple.  IBOC is not 
a proprietary system it is an acronym (as below) for In Band On 
Channel.  Ibiquity has a proprietary system called HD Radio.  I look at 
it the same as real estate.  You might have a right-of-way  for the 
state or town three feet from the curb but when you neighbor dumps his 
garbage there the excuse that it is on state right-of-way (within the 
mask) does not cut it.


Craig Bowman
Durand, MI


Goran Tomas wrote:
> --- At 22.4.2007 09:30, Glen Kippel wrote: ---
>> On 4/22/07, Goran Tomas <gtomas.lists at gmail.com> wrote:
>>>
>>> I'm writing an article on digital broadcasting systems and I'm
>>> looking for some information.... So, what is the typical bitrate used
>>> for digital AM (IBAC)? What is the maximum bitrate that can be used?
>>> I suppose IBAC uses HDC codec?
>>>
>>> -------------
>>
>> IBAC?  How could that be IBAC, since that stands for "In-Band, Adjacent
>> Channel"?  Like, a station on 1000 kHz having a digital on 1010?  I 
>> thought
>> IBAC was considered for use on FM, on the even frequencies -- 100.8, for
>> example, but the whole idea was shot down some years ago.  Now the 
>> plan is
>> "In-Band, On Channel" -- IBOC.  Anyway, I don't know the bitrate.  
>> You might
>> check with iNiquity, as it's their proprietary system.
>
> From the discussions here it somehow got stock with me that the AM 
> system is IBAC and FM IBOC... If that's not true, my mistake. I 
> haven't really paid attention on the transmission side of this. 
> Though, looking now at the occupied spectrum of iBiquity's AM system 
> it does extend all the way to the 15kHz on each side...
>
> Anyway, I'm interested in bitrates and codecs. In reading some of the 
> iBiquity papers, it looks like 20kbps is available for audio? I'm not 
> sure if service mode MA2 doubles that to 40 kbps or just increases 
> robustness in case one sideband is undecodable?
>
>
> Regards,
> Goran Tomas 
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