[opendtv] Re: Freeview business model
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Tue, 30 Jan 2007 16:17:38 -0500
Dale Kelly wrote:
> In principle such a wideband system makes sense but
> as a practical matter, it's impractical :~)- for
> several reasons:
> 1. Wideband transmitters have significant power output
> limitations and I'm not aware of any technology* that
> can operate many channels wide with any amount of
> power.
> 2. TV transmitters that multiplex signals must
> generally operate near the Class A mode (very linear)
> to minimize intermodulation. That is also the least
> efficient mode of operation.
Agreed. Wide band means low Q by definition, therefore less efficient.
However, the higher you go up the UHF band, the more practical this
might be. Right?
For example, suppose in a given market you're given channels 46-51,
663-693 MHz. That's to provide the somewhat typical 6 channels the
smaller markets get. The efficiency of that transmitter would be higher
than that of a single transmitter on Channel 2. It would be higher than
a transmitter on Channel 6, but a little lower than a transmitter on
Channel 7.
But of course, the single point of failure is created. So then you need
to back it up.
Bert
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