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fmpower

Signal with power-law frequency modulation

Calling Sequence

[X,IFLAW] = fmpower(N, K, P1)
[X,IFLAW] = fmpower(N, K, P1, P2)

Parameters

N :

a positive integer: number of points in time

K :

a real scalar degree of the power-law (K~=1)

P1 :

a real 2 elements vector:

if the number of input arguments is 2, P1 is a vector containing the two coefficients [F0 C] for an hyperbolic instantaneous frequency .

if the number of input arguments is 3, P1 is a time-frequency point of the form [t,f]. where t is in seconds and f is a normalized frequency (between 0 and 0.5).

P2 :

a real 2 elements vector:

P2 is a time-frequency point of the form [t,f]. where t is in seconds and f is a normalized frequency (between 0 and 0.5).

X :

real column vector: the modulated signal time samples. Sampling frequency is set to 1.

IFLAW :

real column vector: instantaneous frequency law

Description

fmpower generates a signal with a power-law frequency modulation. X(t) = exp(j*2*pi(F0*t + C/(1-K)*abs(t).^(1-K))). When called with 4 input arguments F0 and C are derived from P1 and P2 such that the frequency modulation law fits the points P1 and P2.

Examples

[X,IFLAW] = fmpower(128,0.5,[1 0.5],[100 0.1]);
clf
subplot(211); plot(real(X));
subplot(212); plot(IFLAW);

See also

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