Re: CM11A hangup: Any better products?

[George Pontis <gpontis@xxxxxxxxxxx>]

In article <430b693e.57302636@xxxxxxxxxxxxx>, nobody@xxxxxxxxxxxx says...
> Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> >What I found with X-10 modules a lot was that their resonant circuit was
> >quite far out of tune. That made a huge difference in some. The
> >receivers were ok (not great) but they were listening on the wrong
> >frequency until adjustment. Since it's an AM protocol a strong signal
> >will still get through.
>
> I'm curious how you determined that the modules were mistuned.
>
> I've looked at the frequency of several X-10 transmitters and found all to
> be at 120kHz.


The transmit frequency is controlled by the crystal or resonator, which is usually
quite accurate. The transformer (X2 in the powerlinc circuit) is part of a tuned
circuit that may not be perfectly tuned to 120KHz. If not, then the receive signal
coupled through C5 will be smaller at 120Khz. Transmit operation is not affected
very much by a small mistuning; the transmit current will increase and that is
about all.