Signal with power-law frequency modulation
[X,IFLAW] = fmpower(N, K, P1) [X,IFLAW] = fmpower(N, K, P1, P2)
a positive integer: number of points in time
a real scalar degree of the power-law (K~=1)
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).
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).
real column vector: the modulated signal time samples. Sampling frequency is set to 1.
real column vector: instantaneous frequency law
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.
[X,IFLAW] = fmpower(128,0.5,[1 0.5],[100 0.1]); clf subplot(211); plot(real(X)); subplot(212); plot(IFLAW); | ![]() | ![]() |