s to r

[farky]

Here's the circuit I had set up today that almost worked for square to 
ramp:

split the signal path
put one square wave through an op amp integrator, with supply voltage at 
0 and 9v
put the other square wave through an inverter, then through an op amp 
integrator with 
supply voltage as above.  (the input square (at the beginning of the 
chain) is at 0-9v)

now linearly mix the two signals. (each signal is a sawtooth with half of 
its blades missing)
we're combining two 180 degree out of phase partial saws.

Here's what happened:

there was some output error voltage, but I did have a sawtooth.  The 
problem was that one of the saw waves wasn't hitting zero so it appeared 
that we had a double length wave with two teeth per cycle.

How do we get rid of the DC?  Capacitors on the output of the amps?

I'll keep trying.


toby