From: "Alan B. Pearce"

> Yeah, IIRC it is carrier off/on. But I was figuring that one could
detect

Alright, enough is enough.  ;-)  The carrier is never turned off, it is
reduced in power by 10dB at the start of each second.  It is then
restored to full power at either 200mS, 500mS or 800mS later.  This
conveys a binary 0, a binary 1 or a position marker respectively.  I
wonder how they do that without causing any phase/frequency distortion.

> PLL lock to obtain the data. Probably a long winded way to go about
things,
> but it was something I had considered for a long time, but never got
around
> to really forming ideas up. I do suspect that one would need some form
of Rf
> amplification to make a decent go of it, but it was one of those "I
wonder
> if I could ..." ideas.
>
> I know that Temic used to have a small chip that was ideal as a
receiver, to
> recover the data signal. One of my colleagues used to have one here
blinking
> an LED with the received data, but I cannot see it at the moment.
There are
> probably other suitable chips as well, most likely some form of TRF
system
> than anything else.
>
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