low121                package:RTisean                R Documentation

_L_o_w _p_a_s_s _f_i_l_t_e_r

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

     Applies a simple low pass filter in the time domain.

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

     low121(series, l, x = 0, c = 1, i = 1)

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

  series: a vector or matrix.

       l: number of data to use. 

       x: number of lines to be ignored. 

       c: column to be read. 

       i: number of iterations. 

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

     Applies a simple low pass filter:

                   x'[n] = (x[n-1]+2*x[n]+x[n+1])/4

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

     A vector consisting of the filtered time series.

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

     ## Not run: 

     numdata <- 500
     dat <- cos(1:numdata/25)+rnorm(numdata,0,0.1)
     plot(dat,xlab="Time",t="l",ylab="Cos Data",ylim=c(-1.7,1.2))
     filteredat <- low121(dat,i=10)
     points(filteredat,col=2,t="l",lwd=2)
     legend(300,-1.3, c("Noisy Data","Filtered Data"),fill=c(1,2), bty="n")

     ## End(Not run)

