90-degree phase tri lfo revisited

[Tom May]

A while back someone was asking about an lfo with 90-degree phase
shifted triangle outputs.  You can get arbitrary phase shifts by
starting with a saw oscillator, going through an ElectroNotes sawtooth
phase shifter, and then a saw to tri converter.  Ok, you'll need a
converter for the non-shifted saw, too.  No doubt more work than some
of the other solutions presented here, but hey, you're not limited to
90 degrees of phase shift.

Here's another use for the EN saw shifter: take a saw from an audio
frequency vco, shift it using an LFO saw as a control voltage to
determine the amount of shift (you want the shift to go from 0 to 360
degrees on each LFO cycle), and sum it back with the unshifted signal.
You've now got two saw waves that beat against each other at the LFO
frequency regardless of the audio frequency.  Not super-spectacular,
the main point just being that the beating doesn't vary with pitch or
rely on tracking of two oscillators.  You can of course wave shape the
saws to get other beating waves.  The saw shifter circuit works out
very neatly when both audio and LFO saws have the same voltage swings.

fTom.

(Back on the list after about a two-year hiatus.  The traffic seems to
have increased.  Or my time has decreased.  Going by "fTom" on this
list because there seems to be at least one other "Tom" now.)