[sdiy] chaotic sound/analog computer

[Simon Brouwer]

Derek Holzer schreef:
> Hi folks,
>
> I've been reading a great article on "Chaotic Sound Synthesis" (Dan
Slater, Computer Music Journal Summer 1998--first page can be
> previewed at http://www.jstor.org/pss/3680960 ). In this article, he
presents a block diagram of the Ueda attractor, "a second-order
> nonlinear differential equation that can be readily solved by an analog
computer". Slater continues:
>
> "The Ueda attractor is similar to a state variable filter, except that
the inverting stage has been replaced with an x³ circuit and the signal
input is connected to the first integrator stage. The Ueda attractor is
based on a ring-circuit topology that includes a pair of integrators and
an x³ function. A chaotic system requires both
> feedback and nonlinearity. The feedback is provided by the
> ring-circuit topology, and the nonlinearity is provided by the x³
circuit. The x³ circuit can be constructed from a pair of analog
multipliers."
>
> The crucial part of the diagram that I can't work out how to cube the
signal. What would work for something like that? Something using an OTA?
Two four-quadrant multipliers? Can anyone point me to a suitable circuit
for getting the cube?

Two multipliers, of which one should be four quadrant and the second may
be two-quadrant (such as an OTA)

Use the four-quadrant multiplier with the input signal x to obtain x*x,
which is always positive. It may be applied to the control input of a
two-quadrant multiplier to multiply with x obtaining x*x*x.

-- 
Vriendelijke groet,

Simon Brouwer
-*- nl.openoffice.org -*- http://www.opentaal.org -*-



-- 
Vriendelijke groet,

Simon Brouwer
-*- nl.openoffice.org -*- http://www.opentaal.org -*-