160 baud ALDL data stream format - reference URL?

[jsg at donet.com]

   In message <B0B0BB04D8ABD111937800805FEA5B1D02123384 at exchou-prod1001.eng.hou
.compaq.com>, you write:
 
<delete>

| should this be:
|                S   0        1    S
|            ..__     ........_____    ...
|                |   ^        ^    |   ^
|                V___|........|    V___|.. 
|               T0   T2       T2  T3
| 
| 		  t2-t0 > t3-t2 => 0
| 		  t2-t0 < t3-t2 => 1


yes, t2 (the rising edge time) should be used in the equation.


| I would think that the transition from low to high would be where the
| timestamp
| should happen.  If it occurs early it is a zero and if it occurs late it is
| a one.


It's the ratio of high time versus low time that is important.
Without going through the math, I believe an optimal Bayes detector
for this problem would integrate the "1" and "0" time and compare the
ratio to a fixed value (a threshold based on expected duty
cycle... assumed 1 in this case). The above differences are an
implementation of the integration given transition times. Other
solutions would not be optimal in this sense.

john gwynne