Hybrid vs All-digital modes

[Len14043]

I have been following the development of HD radio for the past year and have a question. I understand there are 2 modes: Hybrid and All-digital. To preserve the analog part of the signal, they are starting with the hybrid mode. I was curious if the 2 digital modes are either/or, or can a station gradually switch to the all-digital mode. For instance, suppose a station starts broadcasting in the hybrid mode and after awhile, more people purchase hd radios. Would it be possible to slowly improve the digital signal at the expense of the analog signal? In other words, slowly phase out the analog by reducing bandwidth while increasing it for the digital part of the signal?

 

[k9ez]

> I have been following the development of HD radio for the
> past year and have a question. I understand there are 2
> modes: Hybrid and All-digital. To preserve the analog part
> of the signal, they are starting with the hybrid mode. I was
> curious if the 2 digital modes are either/or, or can a
> station gradually switch to the all-digital mode. For
> instance, suppose a station starts broadcasting in the
> hybrid mode and after awhile, more people purchase hd
> radios. Would it be possible to slowly improve the digital
> signal at the expense of the analog signal? In other words,
> slowly phase out the analog by reducing bandwidth while
> increasing it for the digital part of the signal?
>


There are multiple set ups within the importers that send out the stream to the transmitter. Some are available for when (and IF) the hybrid mode goes away. So you increase your digital bandwidth as you add more channels. I am not sure about decreasing the bandwidth of the analog signal however. My thought was that the analog would stay the same until it would be shut off. I do not know of any plans to limit the bandwidth of the analog signal to add in more digtial.