Patent ID: 7376562

Claim:
A method for determining at least one frequency component that is present in an input signal having a time varying structure, comprising the step of: converting an audio input signal to an electronic representation comprising a time varying input signal x(t); communicating said time varying input signal x(t) to a network of N nonlinear oscillators, each having a different natural frequency of oscillation and obeying a dynamical equation of the form τ n ⁢ z . n = z n ⁡ ( a n + b n ⁢  z n  2 ) + F ⁡ ( z , D ) + G ⁡ ( x , z , S ) + Q ⁢ ξ n ⁡ ( t ) ; selecting a source of said time varying input signal exclusive of said network of nonlinear oscillators; generating at least one frequency output from said network useful for describing said time varying structure, wherein said frequency output is at least one of (a) a frequency that is in the input signal, and (b) a frequency that is related to the input signal by an integer ratio other than a 1:1 ratio; wherein z n is the complex-valued state variable corresponding to oscillator n; τ n >0 is oscillator time scale, a n and b n are complex-valued parameters in which a n =α n +iγ n and b n =β n +iδ n ; α n is a bifurcation parameter; γ n >0, together with τ n determines oscillator frequency according to the relationship f=γ n /(2πτ n ); β n <0 is a nonlinearity parameter; δ n is a detuning parameter; F(z,D) defines the non-negligible internal network coupling among the non-linear oscillators having different frequencies; G(X(t),z,S) defines the input stimulus coupling and √{square root over (Q)}ξ n (t) defines internal noise.