Re: Compact Fluorescent Noise

["Jeff Volp" <JeffVolp@xxxxxxx>]

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:4548cbd6.253352156@xxxxxxxxxxxxxxxx

> It would be interesting to see the noise through a wider passband

At your suggestion I monitored the line with just a high-pass filter to
reject 60Hz.

Unfortunately, there seems to be some sort of audio communication device on
the line now because I see apparent audio modulation of a 100mVpp 120KHz
carrier that is there whether or not the CF bulbs are on.  So it is
difficult to determine how much more noise is added by the bulbs.

I did confirm the noise pulsation is due to beating between the bulbs by
removing all but one.  The CF bulb causing this havoc is the TCP ESN18.

Bottom line is that if you use CF bulbs in an automation environment, it is
a good idea to isolate those circuits with the Leviton 6287 noise block.  We
have those on all X10 controlled lighting circuits, and have never had a
problem with any of those CF bulbs.

One other thing I noted while looking at the scope photos is that timing of
X10 bursts at other than the zero crossing is not well defined.  Please look
at the following two photos:

http://jeffvolp.home.att.net/x10xmtbuf/linenoise1.jpg

http://jeffvolp.home.att.net/x10xmtbuf/linenoise2jpg

Notice how the X10 bursts move from one sample to the next.  Also note the
zero crossing burst is fixed as is the line transient just after the center
zero crossing.  That third burst moves just about 1mS, and I don't see how
it could hit the reception window in a three-phase system.  Signals were
transmitted from a RR501 in response to a palmpad.

Jeff