Re: Cause of some major X10 problems found

["Jeff Volp" <JeffVolp@xxxxxxx>]

The XTB-IIR was not connected to a controller, so I have no traffic log.
However, I did capture a valid data string on the 7D01 logic analyzer.  I
did not take a photograph of it, but it did look like just a series of 1-0
pairs.  I have since modified the XTB-IIR AGC loop to increase the threshold
when it sees a number of X10 messages having non-complimentary 1-0 patterns.
After that mod, I have never seen it respond to CFL noise.  In fact, it can
recover a X10 signal riding on top of 1Vpp of pulsating CFL noise.

Jeff

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:46e6add2.1607416109@xxxxxxxxxxxxxxxx
> "Jeff Volp" <JeffVolp@xxxxxxx> wrote:
>
>>"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
>>news:46e77e9f.1595333671@xxxxxxxxxxxxxxxx
>>> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>>>
>>> The probability that a noise source will create valid X-10 PLC codes
>>> (1110
>>> followed by manchester encoded data synchonized to powerline
>>> half-cycles)
>>> out of whole cloth is near zero - it ain't gonna happen. However, there
>>> are
>>> other explanations for the unwanted ONs & OFFs - see the link I cited in
>>> my
>>> response to Bruce.
>>
>>It may be near zero, but I have documented on my logic analyzer that it
>>can
>>happen.  You may remember an earlier post regarding beating compact
>>fluorescent lights producing peaks and valleys similar to a X10
>>transmission.  I found that about 2 minutes after I switch on my CFL
>>"noise
>>generator" the beat frequency between a couple of the bulbs gets low
>>enough
>>that the peaks and valleys occur on alternate half cycles.  If the
>>receiving
>>module just happens to catch enough noise 3 times in a row to recognize a
>>start pattern, the remainder of the message with alternating 1-0's does
>>get
>>through as a valid command.  Even with the enhanced error detection
>>requiring complimentary 1-0's, I did capture one squeaking through.
>
> How many valid codes were logged by your Ocelot or Leopard?
>
> If I understand you correctly, the majority of such generated codes would
> be
> M-13 or J-Status Request as they are the only ones that have alternating 1
> and 0 manchester patterns. All others will have some 11 or 00 sequences at
> the manchester level.