Generate stabilization diagram for modal analysis

`modalsd(`

generates a stabilization diagram in the current figure.
`frf`

,`f`

,`fs`

)`modalsd`

estimates the natural frequencies and damping
ratios from 1 to 50 modes and generates the diagram using the least-squares
complex exponential (LSCE) algorithm. `fs`

is the sample
rate. The frequency, `f`

, is a vector with a number of
elements equal to the number of rows of the frequency-response function,
`frf`

. You can use this diagram to differentiate between
computational and physical modes.

`modalsd(`

specifies
options using name-value pair arguments.`frf`

,`f`

,`fs`

,`Name,Value`

)

returns a cell array
of natural frequencies, `fn`

= modalsd(___)`fn`

, identified as being stable
between consecutive model orders. The *i*th element contains a
length-*i* vector of natural frequencies of stable poles.
Poles that are not stable are returned as `NaN`

s. This syntax
accepts any combination of inputs from previous syntaxes.

[1] Brandt, Anders. *Noise and Vibration Analysis:
Signal Analysis and Experimental Procedures*. Chichester,
UK: John Wiley & Sons, 2011.

[2] Ozdemir, Ahmet Arda, and Suat
Gumussoy. "Transfer Function Estimation in System
Identification Toolbox™ via Vector Fitting." *Proceedings of the 20th World Congress of
the International Federation of Automatic Control*, Toulouse, France,
July 2017.

[3] Vold, Håvard, John Crowley, and G. Thomas Rocklin.
“New Ways of Estimating Frequency Response Functions.” *Sound
and Vibration*. Vol. 18, November 1984, pp. 34–38.