Bi-pulse convertor (ON-topic)

[Magnus Danielson]

From: "danial stocks" <diode at hotmail.com>
Subject: Re: Bi-pulse convertor (ON-topic)
Date: Fri, 29 Dec 2000 01:27:17 

> >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.

> also probs with phase inversion?

Phase inversion? Please elaborate!

> 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...

Cheers,
Magnus