Re: Converting Heidenhain Scale to sq wave

Brial:

I believe that the "CMOS Cookbook" by Don Lancaster mentioned by Jan
has a section on Op-Amps.

I don't have my copy handy, maybe someone could check on that.

You will want to configure a pair of these as "Comparitors" (one for
each quadrature phase), with the reference at the ground level (if
using a double ended power supply) or at the midpoint between the B+
and Ground (single ended power supply), this will give you a nice
square wave. Run that into one of the Schmidt Triggers that Jan also
mentioned, to get your TTL Levels.
Or most any TTL gate for that matter, any high speed type would be
best.
The Quadrature Signal does not really matter if it's inverted or not.

I forgot about your reference signal. That will need an Op-Amp also.

The CA3260 is a nice dual Op-Amp that is user friendly.
I don't have those specs handy either, you may or may not want
something faster.

Do a little breadboarding, the circuit should end up quite simple.

An alternative is just to use a simple transistor amplifier, such as
a 2N2222 instead of the Op-Amps.
Your duty cycle would most likely not be 50/50. Depends on you
required accuracy.

Tom M.

--- In CAD_CAM_EDM_DRO@y..., JanRwl@A... wrote:
> In a message dated 19-Aug-02 19:27:14 Central Daylight Time,
> bdrmachine@h... writes:
>
>
> > Question: Has anyone converted this signal to 5 volt TTL levels?
> > If so please share the circuit diagram with me. If not (after I
> > reinvent the wheel) I will follow up with a future post and let
you
> > all know what I found out.
> >
> Brian: Nothing magic here! Just run the signals through a 74HCT14
or
> 74HCT541, Schmidt Triggers, and let the chip do the work!
>
> The '14 in inverting, so you might have to use TWO gates per input
to
> "re-invert" the signal so you have non-inverting. But in the '541,
you have
> EIGHT non-inverting buffers!
>
> If you haven't a clue about such, get Don Lancaster's CMOS
Cookbook. It had
> gobs of data and "how-to", but the "data sheets" for IC's in it is
outdated.
> There are many more now available (such as the cited '541) not in
the book.
>
> Jan Rowland
>