VSS importance

[Bruce Plecan]

-----Original Message-----
From: Mike Hoenes <MHoenes at dhr.state.nc.us>
To: Jake Sternberg <chickens at ccwf.cc.utexas.edu>;
diy_efi at esl.eng.ohio-state.edu <diy_efi at esl.eng.ohio-state.edu>
Date: Monday, September 28, 1998 1:00 PM
Subject: RE: VSS importance


>anyone figure out how to get a 730  with a 91 L98 eprom to accept input
from
>a 2000ppm vss?


Been figuring but not done yet.

I'm assuming you want a 4000ppm, and only have a 2000ppm.
What I think will work is use two 555 as monostables.  Trigger
one off the - edge of the input signal, and one off of the + edge,
then combine the two signals with a 4011 or some such, tie
that to a Mosfet, and a resistor off of that and use the resistor's
input as the VSS signal.

______            ______            ______            ______
             I_____I             I_____I             I_____I

______   ___    ____    _____    ____   ____    ____
             I_I      I_I          I_I           I_I         I_I         I_I

Hard to type with Doc laughing at my wave patterns
Maybe some EE has input?.
Cheers
Bruce