# tfestimate

Transfer function estimate

## Syntax

## Description

finds a transfer function estimate between the input signal
`txy`

= tfestimate(`x`

,`y`

)`x`

and the output signal `y`

evaluated at a set of frequencies.

If

`x`

and`y`

are both vectors, they must have the same length.If one of the signals is a matrix and the other is a vector, then the length of the vector must equal the number of rows in the matrix. The function expands the vector and returns a matrix of column-by-column transfer function estimates.

If

`x`

and`y`

are matrices with the same number of rows but different numbers of columns, then`txy`

is a multi-input/multi-output (MIMO) transfer function that combines all input and output signals.`txy`

is a three-dimensional array. If`x`

has*m*columns and`y`

has*n*columns, then`txy`

has*n*columns and*m*pages. See Transfer Function for more information.If

`x`

and`y`

are matrices of equal size, then`tfestimate`

operates column-wise:`txy(:,n) = tfestimate(x(:,n),y(:,n))`

. To obtain a MIMO estimate, append`'mimo'`

to the argument list.

computes
a MIMO transfer function for matrix inputs. This syntax can include
any combination of input arguments from previous syntaxes.`txy`

= tfestimate(___,'mimo')

`[`

returns a vector of frequencies, `txy`

,`f`

] = tfestimate(___,`fs`

)`f`

, expressed in terms of
the sample rate, `fs`

, at which the transfer function is
estimated. `fs`

must be the sixth numeric input to
`tfestimate`

. To input a sample rate and still use the
default values of the preceding optional arguments, specify these arguments as
empty `[]`

.

`tfestimate(___)`

with
no output arguments plots the transfer function estimate in the current
figure window.

## Examples

## Input Arguments

## Output Arguments

## More About

## Algorithms

`tfestimate`

uses Welch's averaged periodogram
method. See `pwelch`

for details.

## References

[1] 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.

## Extended Capabilities

## Version History

**Introduced before R2006a**

## See Also

`cpsd`

| `mscohere`

| `periodogram`

| `pwelch`