On 1/20/14 9:20 AM, Jim Lux wrote:
Interestingly, it occurred to me that one could just add a sufficiently
large deviation random number to the period each time to dither it.
The "rate" changes once per hour (per tvb's EOT routine), so there's
3600 ticks at a given rate. If I were to vary the rate (as set to the
routine) by, say, +/- 50 microseconds, the truncation to 16 microsecond
chunks will average out over the 3600 ticks in an hour. A quick
simulation shows sd of 1/2 microsecond for the result.
You need to add an 8 microsecond offset, because the SetPeriod routine
truncates, rather than rounds.
I'd like to keep it all in high level Arduino land, rather than delving
into counting cycles and ticks at a low level: makes it easier to move
to a new platform.
new dither code:
long newper = 1000000+ratedelta + 8 + random(-DITHERWIDTH,
DITHERWIDTH);
Serial.println(newper);
Timer1.setPeriod(newper);
Seems to work ok.. (ran for a few minutes, checked the average period, etc.)
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