chirp                 package:signal                 R Documentation

_A _c_h_i_r_p _s_i_g_n_a_l

_D_e_s_c_r_i_p_t_i_o_n:

     Generate a chirp signal.  A chirp signal is a frequency swept
     cosine wave.

_U_s_a_g_e:

     chirp(t, f0 = 0, t1 = 1, f1 = 100, form = c("linear", "quadratic", "logarithmic"), phase = 0)

_A_r_g_u_m_e_n_t_s:

       t: array of times at which to evaluate the chirp signal. 

      f0: frequency at time t=0. 

      t1: time, s. 

      f1: frequency at time t=t1. 

    form: shape of frequency sweep, one of "linear", "quadratic", or
          "logarithmic". 

   phase: phase shift at t=0. 

_D_e_t_a_i_l_s:

     'linear' is:


                      f(t) = (f1-f0)*(t/t1) + f0


     'quadratic' is:


                     f(t) = (f1-f0)*{t/t1}^2 + f0


     'logarithmic' is:


                      f(t) = (f1-f0)^{t/t1} + f0

_V_a_l_u_e:

     Chirp signal, an array the same length as 't'.

_A_u_t_h_o_r(_s):

     Original Octave version by Paul Kienzle. Conversion to R by Tom
     Short.

_R_e_f_e_r_e_n_c_e_s:

     Octave Forge <URL: http://octave.sf.net>

_S_e_e _A_l_s_o:

     'specgram'

_E_x_a_m_p_l_e_s:

     ch = chirp(seq(0, .6, len=5000))
     plot(ch, type = "l")

     # Shows a quadratic chirp of 400 Hz at t=0 and 100 Hz at t=10
     # Time goes from -2 to 15 seconds.
     specgram(chirp(seq(-2, 15, by=.001), 400, 10, 100, "quadratic"))

     # Shows a logarithmic chirp of 200 Hz at t=0 and 500 Hz at t=2
     # Time goes from 0 to 5 seconds at 8000 Hz.
     specgram(chirp(seq(0, 5, by=1/8000), 200, 2, 500, "logarithmic"))

