freq. doubler

Stewart Pye stew at
Mon Mar 6 09:55:49 CET 2000

Hi Toby...

Take a sine, saw or triangle wave. 
1. full wave rectify it using a precision full wave rectifier. 
2.Put this into one input of a comparator. Put a steady voltage into the
other input. you now have an adjustable pulse width rectangular wave. Trim
the voltage until you get a square wave. Of course you could have pwm if
you want. (Part 2 is just a standard pwm circuit) that is used in most
synths. There's a few more things to deal with.. if you want to do it this
way feel free to ask for more advice. Parts count: 3 op amps (1 quad) or
maybe 2,  and a few resistors.

At 08:35 PM 05/03/2000 -0000, farky wrote:
>Hey folks.
>I'd like to make a square wave or triangle or sine wave frequency doubler 
>that maintains 50% pulse width.  I've been thinking so much about this, I 
>feel like Phaedrus.  Any simple ideas?
>synth-diy at

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