Arbitrary phase calculation (was: Ensemble Circuit Configuration Questions)

[Martin Czech]

Before starting a lot of complicated circuitry, one should consider
that a sync feature is a usefull thing for lfos. Ie. sync to a given
point (v.c.).  It is a good feature to start a note at a desired phase
angle. If you take two lfos, one as master and one as slave, about the
same frequency, you can obtain different phase shifts. Of course, the
phase shift can not be rapidly changed.  You could do a "sync to most
negative point" with pwm input as well, the moving edge of the pwm will
determine the relative phase then.

Now, this creates steps if the sync point is rapidly changed. OTOH what
sense does it make to have a phase difference that is constantly changing,
we could start with a beat frequency right away.

Another feature could be that sync is only allowed inside a narrow window,
this would not allow large steps. A little frequency modulation should
suffice to get into the window. It would require some beating and some
run in time.

These are all features that one could expect from a large lfo, nothing
special.

However:

The easiest way seems to be the multiwaves idea for sawtooth (I have
forgotten the original title). It is just combining pwm with a saw wave
(same frequency, pwm average is null) and gives multiple saw waves with
the same frequency , but arbitrary phase. Perhaps this scheme could be
changed to work with triangle waves, I don't know yet, if not, well use
a saw->tri converter.


m.c.