Re: x10 Help

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:46fc66bf.3031012953@xxxxxxxxxxxxxxxx
> Frank Mc Alinden <Frank.Mc.Alinden.2xlj5j@xxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
>
> >Now that the Oz dollar is up around 88 US cents i think i will order a
> >esm1 and see if i can mod it....I just assumed that the U.S. version
> >may have used the mains frequency  as a reference for its 120khz signal
> >???
>
> I'm not sure what you mean. The 120kHz bursts sync to the ZC whatever the
> line frequency. The ESM1 detects ZC and measures the amplitude of the
signal
> at ZC+500µS.

I think what he means is how does the unit discriminate between 120kHz
signals X-10 uses from other frequencies that might be on the powerline.  I
assume they used some sort of tuned circuit that passes 120kHz signals and
rejects others just like an ordinary AM radio tuned to a certain broadcast
frequency.  I don't believe that either the transmitters or receivers depend
on line frequency to determine the 120kHz frequency.  That would most likely
be determined by the values of components used to create the oscillators and
receiving circuits.  But I certainly can see why Frank might have made that
assumption, particularly since 120kHz is a multiple of 60Hz, albeit a very
high one

--
Bobby G.