0-5V square wave to sine wave with zero crossing?

 

Hi, I was wondering if you guys could help me with a little problem. I
am swapping transmissions in my car and the new transmission uses a
different type of speed sensor. My original transmission uses a
variable reluctor that generated a sine wave. My new transmission uses
a sensor that generates a 0V to 5V square wave. I was wondering if
anyone know how i could convert me 0V to 5V signal to a sine wave with
a approx 10Vpp. My freshman year i play with a XR2206 function
generator IC. But I have no idea how to make it work to solve my
problem. I was also thinking about using a op-amp summer with a gain of
about 2 and adding a negative offset.  Any advice would be helpful.

 

newsrichie@yahoo.com wrote:

The signal you create from the variable reluctance pickup can not
exactly duplicate the square wave sensor in one respect.  It cannot
work all the way to zero speed.  That may not be important, but this
needs to be verified.

A pretty good way to convert the VR pickup to digital output is to
clamp it with a pair of Schottky diodes (and possibly a series
resistor) so that it has a peak swing in each direction of about .3
volts.  Then pass that through an LM393 comparator with a pull up
resistor on the output to +12.  The comparator can handle a swing .3
volts below ground, with the other input at ground and give a nice
clean square wave output.  The chip container 2 comparators, so you
need to ground the inputs of the second half to park it.

http://www.fairchildsemi.com/ds/LM/LM393.pdf

 

John Popelish wrote:

Hey, John -

I think he wants to go the other way (make a sine from a rectangular signal).

Or I'm not reading it right, in which case, oops!

John

 

John - KD5YI wrote:

Yep, you're right.  Never mind.

 

Hello John,


The only way I could figure doing that would be to sync some kind of
function generator chip to it. If that sync has a wide enough range for
this case. Or use a micro controller's PWM feature.

Regards, Joerg

http://www.analogconsultants.com