[sdiy] Hopf bifurcation VCOs

[Ian Fritz]

At 10:21 AM 11/11/05, Don Tillman wrote:
>    > Date: Thu, 10 Nov 2005 20:11:47 -0700
>    > From: Ian Fritz <ijfritz at earthlink.net>
>    >
>    > Anyone have other favorite sinusoidal quadrature oscillators?
>
>Well... yeah!
>
>   "A Quadrature Trapezoid Voltage Controlled Oscillator"
>   http://till.com/articles/QuadTrapVCO/index.html

I don't see anything there about ***sinusoidal***. Please show me what I am 
missing.