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Posted by Brian Gregory [UK] on 09/24/07 18:08
"Green Xenon [Radium]" <glucegen1@excite.com> wrote in message
news:46f73fc6$0$32520$4c368faf@roadrunner.com...
> On Sep 23, 3:02 pm, Brendan Gillatt
> <brendanREMOVET...@brendanREMOVETHISgillatt.co.uk> wrote in
> http://groups.google.com/group/uk.tech.digital-tv/msg/4c903b0a453a39fa :
>
> Ive tried painfully hard to answer my questions doing my own research --
> including reading information from books. I still havent found answers to
> my questions. That is why I am turning to NGs for assistance.
>
> Is Quadrature Frequency Modulation used? What for?
>
> AFAIK, Quadrature Amplitude Modulation uses a combo of AM and
> Phase-Shift-Keying.
>
> So QFM would use a combination of FM and PSK. Would this decrease the
> bandwidth required for broadcasting FM luminance video signals?
>
> I did a Google Search for Quadrature Frequency Modulation on
> http://www.google.com/search?hl=en&lr=&q=%22Quadrature+Frequency+Modulation+%22&btnG=Search
>
> None of those pages made any sense to me.
I had a quick look at a few of them.
Some guy seems to be trying to patent something he calls Quadrature
Frequency Modulation. I see this as similar to the many perpetual motion
machines that get patented.
If it works at all I can't see it offering anything different from QPSK (aka
QAM4) in performance or bandwidth requirements.
--
Brian Gregory. (In the UK)
ng@bgdsv.co.uk
To email me remove the letter vee.
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