On Thu, 23 Aug 2007 11:45:30 +0100, "Keith G"
wrote:


"Don Pearce" wrote in message
...
On Thu, 23 Aug 2007 03:05:30 +0100, "Keith G"
wrote:


I don't mind admitting that most of the information on this page:

http://www.apah69.dsl.pipex.com/show/Tuner.JPG

flies right over my head, but it's all very interesting! What is
paragraph 5 saying - that my *analogue* tuner is carrying out A/D and
D/A conversions..??



No. It is making the audio output the same way a class D amplifier
does. It generates pulses of constant width and measures their average
level. When the frequency is higher, they are closer together and the
average level goes up. When the frequency is lower they are further
apart and the level goes down. That gives you your audio from the
frequency modulation.


OK, like in the diagram:

http://www.apah69.dsl.pipex.com/show/Brochure01.JPG

Which I see as:

1) Wiggly line
2) Chunks
3) More chunks
4) Even more chunks
5) Wiggly line again...

You know what my next question would be, don't you? :-)

(The words 'modem', 'analogue signal' and 'why bother' would figure in
it, I suspect...)



Would you mind awfully if we didn't go there? ;-)

d

--
Pearce Consulting
http://www.pearce.uk.com