% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/nonparam.R
\name{spa}
\alias{spa}
\title{Estimate frequency response}
\usage{
spa(data, npad = 255)
}
\arguments{
\item{data}{an \code{idframe} object}

\item{npad}{an integer representing the total length of each time series
to analyze after padding with zeros. This argument allows the user to
control the spectral resolution of the SDF estimates: the normalized
frequency interval is deltaf=1/npad. (Default: 255)}
}
\value{
an \code{idfrd} object containing the estimated frequency response
}
\description{
Estimates Frequency Response with fixed frequency resolution using
spectral analysis
}
\details{
The function calls the \code{SDF} function in the \code{sapa} package to
compute the cross-spectral densities. The method used is \strong{Welch's
Overlapped Segment Averaging} with a normalized \strong{Hanning} window.
The overlap used is 50%.
}
\examples{
data(frf)
frf <- spa(data)
}
\references{
Arun K. Tangirala (2015), \emph{Principles of System Identification:
Theory and Practice}, CRC Press, Boca Raton. Sections 16.5 and 20.4
}
\seealso{
\code{\link[sapa]{SDF}}
}