simchirp             package:wavethresh             R Documentation

_C_o_m_p_u_t_e _a_n_d _r_e_t_u_r_n _s_i_m_u_l_a_t_e_d _c_h_i_r_p _f_u_n_c_t_i_o_n.

_D_e_s_c_r_i_p_t_i_o_n:

     This function computes and returns the coordinates of the
     reflected simulated chirp function described in Nason and
     Silverman, 1995. This function is a useful test function for
     evaluating wavelet shrinkage and time-scale analysis methodology
     as its frequency changes over time.

_U_s_a_g_e:

     simchirp(n=1024)

_A_r_g_u_m_e_n_t_s:

       n: The number of ordinates from which to sample the chirp
          signal.

_D_e_t_a_i_l_s:

     This function computes and returns the x and y coordinates of the
     reflected chirp function described in Nason and Silverman, 1995. 

     The formula for the reflected simulated chirp is  *formula*

     The chirp returned is a discrete sample on 'n' equally spaced
     points between -1 and 1.

_V_a_l_u_e:

     A list with two components: 

       x: a vector of length 'n' containing the ordered x ordinates of
          the chirp from -1 to 1.

       y: a vector of length 'n' containing the corresponding y
          ordinates of the chirp.

_R_E_L_E_A_S_E:

     Version 3.5.3 Copyright Guy Nason 1994

_E_x_a_m_p_l_e_s:

     #
     # Generate the chirp
     #
     #test.data <- simchirp()$y
     #ts.plot(test.data)

