freq. mult.

[Don Tillman]

   Date: Tue, 28 Nov 2000 00:45:19 +0800
   From: Toby Graves <carpet8 at mac.com>

   i've been working on a problem of frequency multiplication of square waves.
   I want to end up with a nice equal pusle width square wave.  So far, not a
   complete success.   here's what I've tried:

   square->triangle->full wave->comparator->triangle, etc.

   I'm obviously using an integrator for the square to tri.


Try this:

        +---> lossy integrator --> comparator -->
input --+                                        XOR gate --> 2x out
        +--------------------------------------->


The lossy integrator parameters are chosen so that the comparator
output is close to 90-degrees from the original signal over the
frequency range of interest.  It could be a simple RC network.  XORing
two square waves 90-degrees apart gives you a 2x square wave.

  -- Don

-- 
Don Tillman
Palo Alto, California, USA
don at till.com
http://www.till.com