Documenting etfe

2 files changed, 36 insertions, 2 deletions

diff --git a/R/nonparam.R b/R/nonparam.R
index e4d0b07..5b32552 100644
--- a/R/nonparam.R
+++ b/R/nonparam.R
@@ -150,7 +150,23 @@ spa <- function(data,npad=255){
 
 #' Estimate empirical transfer function
 #' 
-#' Estimates the emperical transfer function
+#' Estimates the emperical transfer function from the data by taking the 
+#' ratio of the fourier transforms of the output and the input variables
+#' 
+#' @param data an object of class \code{idframe}
+#' 
+#' @return
+#' an \code{idfrd} object containing the estimated frequency response
+#' 
+#' @references
+#' Arun K. Tangirala (2015), \emph{Principles of System Identification: 
+#' Theory and Practice}, CRC Press, Boca Raton. Sections 5.3 and 20.4.2
+#' 
+#' @seealso \code{\link[stats]{fft}}
+#' 
+#' @examples
+#' data(frf)
+#' frf <- etfe(data)
 #' 
 #' @export
 etfe <- function(data){
diff --git a/man/etfe.Rd b/man/etfe.Rd
index 1e0732e..b0bd836 100644
--- a/man/etfe.Rd
+++ b/man/etfe.Rd
@@ -6,7 +6,25 @@
 \usage{
 etfe(data)
 }
+\arguments{
+\item{data}{an object of class \code{idframe}}
+}
+\value{
+an \code{idfrd} object containing the estimated frequency response
+}
 \description{
-Estimates the emperical transfer function
+Estimates the emperical transfer function from the data by taking the
+ratio of the fourier transforms of the output and the input variables
+}
+\examples{
+data(frf)
+frf <- etfe(data)
+}
+\references{
+Arun K. Tangirala (2015), \emph{Principles of System Identification:
+Theory and Practice}, CRC Press, Boca Raton. Sections 5.3 and 20.4.2
+}
+\seealso{
+\code{\link[stats]{fft}}
 }