Interpolate FRD model
isys = interp(sys,freqs)
isys = interp(sys,freqs) interpolates the frequency response data contained in the FRD model sys at the frequencies freqs. interp, which is an overloaded version of the MATLAB® function interp, uses linear interpolation and returns an FRD model isys containing the interpolated data at the new frequencies freqs. If sys is an IDFRD model, the noise spectrum, if non-empty, is also interpolated. The response and noise covariance data, if available, are also interpolated.
You should express the frequency values freqs in the same units as sys.frequency. The frequency values must lie between the smallest and largest frequency points in sys (extrapolation is not supported).