Re: X10 -> UPB?

[nobody@xxxxxxxxxxxx (Dave Houston)]

James Russo <jr@xxxxxxxxxxxxxxxx> wrote:

>> See p7 of...
>>
>>      http://www.simply-automated.com/documents/UpbDescription_V1.1.pdf
>>
>> They may mean 4 x 40µS bit times - it's really ambiguous as drawn.
>
>I just sat down and started reading some of this. The diagram on page 7
>is clear to me. The UPB data pulse is located within the last 800us of 1
>half cycle. The location of 'noise' that 800us window determines whether
>a 00, 01, 10, or 11 (0,1,2,3) is sent. The window for those is 160us.
>The receiver basically samples at the middle of those 160us windows to
>determine two bits of data..

Huh?

The length of one 60Hz cycle is 16,667µS (1/60).
The length of one-half cycle is 8,333µS (1/120).
The UPB "window" starts at ZC+8000µS (or 333µS before the next ZC).
The total "window" is 160µS, divided into four 40µS segments.
The UPB pulses are expected in the first half of each 40µS segment.

Like I wrote, the drawing is confusing. ;)

Since the "pulses" are actually noise spikes which by definition are of very
short duration (2-3µS), they probably merely look for any rising edge within
the window.