[mythtv-users] Question about Channel frequency tables...

[Steven Dennis]

Hello all.  New to Mythtv, Linux, and the United States TV industry so
I've been swimming in water much too deep.  I'm having a little
trouble understanding the channel frequency tables that mythtv allows
you to chose from.  I would like to understand the difference between
the following:
us-bcast (OTA broadcasts)
us-cable-hrc
us-cable-irc
What are the frequency ranges on each of these?
Do these include digital as well as analogue?

Second
If I am in the US do I need to worry about any digital modulation besides ATSC?

Thanks
Steve