Bi-pulse convertor (ON-topic)

[danial stocks]

>

>
> > >Nope, but let's make one... this is done by using three op-amps and
> > >four resistors...
> > >
> > >                           |\
> > >                       +---|+\    ___
> > >  CV ------------------|-+ |  >--|___|-+
> > >          ___     ___  | *-|-/    1k   |
> > >      +--|___|-*-|___|-* | |/          |
> > >      |   10k  |  10k  | |             *---- Out
> > >      |        |  |\   | | |\          |
> > >      |        +--|-\  | +-|+\    ___  |
> > >Saw -*           |  >-+   |  >--|___|-+
> > >      |        <|-|+/    +-|-/    1k
> > >      |           |/     | |/
> > >      +------------------+
> > >
> > >That ougth to do it. Throw in buffers as required.
> > looks good but I'd add in inverse parallel diode clippers after the 1k 
>res,
> > then mix in an op amp summing stage... this circuit is making the 
>assumption
> > that the + clip on the op amp occours at the same level as the - clip.. 
>and
> > this is not always the case [LM324.. etc ..]
>
>Right, it assumes balanced clip-levels. There are many ways to handle
>this, but in this particular schematic I went for the quick-and-durty
>level just to show how easy it can be. It is not a precission
>curcuit for sure. It is just sufficient to explain how it could work
>and it can also be made to work.
>
>If you assume that the +clip and -clip is fairly stable, then
>individually trim the levels from each op-amp/comparator and then have
>a common offset trimmer should improve the situation alot. Possibly up
>to the level where nobody would preceive much audioble difference.
3 trimmers or 4 diodes? I'd take the diodes myself.. less stuufing around 
calibrating.. but a sep lvl for the + & - pulse setting could be interesting 
as a user controls...



>
> > also probs with phase inversion?
>
>Phase inversion? Please elaborate!
>
never mind about that .. I was thinking back to over driven TL0.. phase 
inversions and looking at this with no feedback path in the op amps.. high 
voltage between the inputs.. prolly nothing to worry over, just out of bed 
so I dont fully got my head on just now..


> > OTOH a comparators should work well here, but the o/p res should
> > be high to the op amp in mix,...
>
>The two output op-amps could very well be comparators.
>
> > also, feeding with a triangle wave will give interesting other 
>waveform..
> >
> > _           _
> > | |___   ___| |___   ___
> >       |_|         |_|
>
>Oh dear...
>
>Have anyone considered what happends if you feed diffrent waveforms
>into this little device? Or maybe just diffrent frequencies...

dont reckon different freq's would change too much  in the waveform unless 
you get to freq limitations of the op amps [pull out all you vintage pre 741 
op amps?] but this could be the basis of an interesting new fx thingo... 
like a distortion, maybe then feed the o/p thru a filter, nothing too 
resonant, just round off the corners a little or something.. maybe you put a 
envelope follower to generate a CV off the incoming audio signal so that the 
volume modulates the pulse width.. ok thats it Im gonna try it out...
Cheers,
Dan


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