Imaginary component of a Frequency Response Function (FRF) calculated using blocking.  There are two forms.

Note: This item is deprecated and will be removed in a future release.

Syntax

Imag_part = BlockFrfImag(vec1, vec2, block_size, overlap)

Imag_part = BlockFrfImag(vec1, vec2, window, overlap)

Arguments

Name

Description

vec1

A vector of input to a system.

vec2

A vector of output from a given system.

block_size

The number of elements to be used for each FRF (should be a power of 2).  Must be a positive integer and not greater than the length of vec1.

window

A vector of window weights to apply to each block.  Its length should be a power of 2.  This length is used as the block_size.

overlap

The number of elements shared between consecutive blocks.  Must be a non-negative integer and less than block_size.

Outputs

Name

Description

Imag_part

A vector of the imaginary component of the FRF.

Example 1

Find the imaginary components of the FRF between the input vector input and the output vector output, using a block size of 256 and an overlap of 128:

Syntax

output = BlockFrfImag(input,output, 256, 128)

Results

output is a vector of the imaginary components.

Example 2

Repeat the above example with a Hanning window instead.

Syntax

output = BlockFrfImag (input,output, HannWin(256), 128)

Results

output is a vector of imaginary components.

Comments

The BlockFrfImag function uses blocking to calculate the imaginary component of a Frequency Response Function (FRF). vec1 and vec2 are assumed to be evenly sampled.  The resultant vector has a number of elements equal to the least power of two greater than or equal to the block_size.

The FRF is complex-valued and used to map time-domain data into the frequency domain.

The BlockFrfImag function is different from a normal FRF in that it introduces blocking.  The input vector is subdivided into blocks, each having block_size number of elements.  An FRF is then performed on each individual block.  The results of these FRFs are then averaged to give the final result.

See Also:

BlockFrfReal

BlockFrfMag

BlockFrfPhase

Fold

Freq