FM Demodulation

On Sun, 21 Jan 2007 11:07:49 -0500, Jerry Avins <jya@ieee.org> wrote:

>Randy Yates wrote:
>> "Mark" <makolber@yahoo.com> writes:
>>> [...]
>>> And re the discussion of analog vs digital, digital may have several dB
>>> advantage in a static situation near threshold like in a space system,
>>> but for a walkie talkie etc, the digital system cliff effect causes the
>>> audio to simply stop 
>> 
>> That's true, but the edge of digital's cliff is quite a bit further
>> away than the bottom of analog's hill.
>
>That's not always a good trade. Riggers prefer a chain that yields at 
>five tons and breaks at seven to one that snaps at ten without warning. 
>Digital systems may be stronger, but they're brittle.
>
>Jerry

Right.   Another "advantage" of analog is that the implementations are
often very small, inexpensive, and consume less power than digital.

There are still applications for analog, but as digital continues to
get cheaper and reduce power consumption they're getting more scarce.

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org

On Sun, 21 Jan 2007 15:24:18 +0800, Steve Underwood <steveu@dis.org>
wrote:

>Mark wrote:
>> Actually most modern analog FM receivers use what is called a
>> quadrature detector which allows the use of a single tank circuit
>> withoiut anytaps or secondaries etc. The performance it equivalnet to a
>> ratio det or a discriminator but is easier to implement and tune..in
>> fact moslty they are implemented with a ceramic or crystal resonantor
>> so no tuning is needed...
>
>This seems to be the case. I did a quick Google for some FM radio chips, 
>and they all seem to have gone back from PLLs to quadrature detectors.

That's what I'm seeing as well.   It's pretty interesting, really,
IMHO.

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org