In a message dated 6/20/2000 11:59:39 AM,
lordgrimley@... writes:
>How does
>a lag processor act like a filter?
Yet another explanation:
Suppose you input a square wave to the LAG PROCESSOR INPUT.
Then adjust the output curve to be linear.
In the ideal case, adjusting the LAG TIME (or amount) will vary the output
from completely flat (i.e., the lag time greatly exceeds the wavelength of
the square wave input ), to an unadulterated square wave.
There will be one spot on the LAG TIME control which would result in the
output having the same period as the square AND the output will show a
triangle wave output but phase shifted by 90 degrees wrt the square input.
Now by careful adjustment of the curve control (and probably some
recalibration of the other controls too) the output can be made to a sine
wave.
In each of these examples it can be seen that one is filtering out harmonics.
Now another idea for the 820 LAG PROCESSOR module:
1) Take a CV source to the input of the 820 (e.g., noise).
2) Take the 820 output to the input of the 100 (or 101) S/H.
3) Take the 100 output to a CV input (say a 1v/oct of an oscillator).
4) Set the lag time to be rather long (like say a 5 octave sweep in thirty
seconds).
5) Set the S/H level all the way up.
This great patch (which I learned from the old Serge manual) keeps step size
small but allows for a full 10V peak to peak swing for the total voltage
output over time. This means that (in the patch example given above) any two
adjacent notes must be close together, but over time a full ten octaves would
be covered. I use this patch with the S/H output going to a VC PANNER
(instead of a VCO) so that a signal may start on the left and slowly pan to
the right and back again. I'm thinking that with judicious use of the curve
control you could make the sound source stay at the extreme left or right
positions with little time in the center. I often use either my sequencer
clock (or keyboard gate) to clock the S/H so that there is no movement while
a sound source is audible.
Try it when you get the chance! It'd be nice to see a simple VC LAG and a
simple S/H module made available to use for these types of uses.
JB