LFOs

[Rob]

I have heard of ppl using this type of scheme to play back lo-fi samples
using a pwm.. Seems insane to me, but I guess. ;)

A guy I used to work with had a past job that dealt with those little cheezy
promotional audio cards and he said that some of the chips used that method
to generate audio without a dac..

Rob

----- Original Message -----
From: Harry Bissell <harrybissell at prodigy.net>
To: Paul Maddox <paul.maddox at ndirect.co.uk>
Cc: Synth-DIY <synth-diy at node12b53.a2000.nl>
Sent: Tuesday, July 04, 2000 1:28 PM
Subject: Re: LFOs


> Is there a (father forgive me) micro in the design.... then drive the LFO
from a
>
> PWM signal out common to all channels.  Integrate with one opamp, and use
the
> other  to
> reverse the polarity. If you use sync on gate, they could all run
together, or
> separatly.  Should not be too hard.
>
> A company took a clever 4-20mA output I designed and replaced my DAC with
a
> PWM... much cheaper than my solution and it worked much better than I'd
have
> expected. At the major carry (7 to 8 bits) is worked BETTER...
>
> H^)  harry
>
> I'd like to see "MIDI CLOCK SYNC" mean that the LFO runs at an intergal
multiple
>
> of the clock, like soft sync.  But what does it REALLY mean ????
>
>
>
> Paul Maddox wrote:
>
> > Dear All,
> >
> >  Ok couple of questions regarding LFOs..
> >
> >   Im developing a polysynth (with the interest of a certain synth
> > manufacturer) and I intend to make it
> > 8 voice poly. Now couple of questions about LFOs,
> >
> >   1) Should I have 8 seperate LFOs or one global? I dont want both.
> >   2) Midi Syncable LFO, Ive been advised that this is something they
would
> > like to see,
> >         someone explain to me what it is, Im guessing that with each
> > successive midi clock received the LFO is
> >         stepped through its waveform. am I right? and if so how do you
tell
> > it how many steps it takes to do a full
> >         cycle, ie 1 beat, one bar, 8bars??
> >    3) I would like the LFO to be voltage controlled (its going to be
> > programmable) and have a sine wave (if the
> >         above point is true then it doesnt matter as its going to have
to be
> > a lookuptable anyway).
> >
> >   oh, I also want it done with just 2 opamps (ie ONE TL072), I need this
> > thing to be compact if Ive got to build
> > 8 voice cards. Trying to find an easy way to do 3 EGs under CV/DIGITAL
> > control. All with as few chips as
> > possible..
> >
> >    Thanks for any help,
> >
> >   Paul Maddox
> > ________________________________________
> > Modulus Synthesiser Website;-
> >     Http://www.noxons.ision.co.uk/
>
>