[sdiy] Single vs Dual Op Amp Supplies

[Neil Johnson]

Hi,

On 8 Mar 2009, at 22:18, Matthew Smith wrote:
> > Yes, you can get A triangle from A square.  However, you need to
> > convert a square of any frequency at, say, 0 to 5 V, to a  
> triangle at
> > that same frequency at 0 to 5 V.  The problem is, the current you  
> send
> > to the integrator will be constant if you simply drop a constant
> > voltage across a resistor, say.  This means that the triangle will
> > have the same slope regardless.  Hence, only one certain frequency
> > will have the same amplitude as the square.  Anything slower will
> > increase in amplitude until the integrator opamp hits the rail.
> > Anything faster will decrease in amplitude until it becomes  
> inaudible.
>
> Understood - this is thus the crux of the matter.

For example, the SGS-ATES M110 provides both squarewave outputs and a  
direct current output proportional to frequency for generating saw  
(simple integrator) or triangle (fancy bidirectional integrator) waves.

Neil
--
http://www.njohnson.co.uk