DFD Arbitrary Group Delay Design VI

Digital Filter Design VIs and Functions

previous page next page
DFD Arbitrary Group Delay Design VI

Owning Palette: Special Filter Design VIs

Installed With: Digital Filter Design Toolkit

Creates an allpass filter with a group delay that you specify.

The group delay in the new filter is optimal in terms of the least pth norm.

Example

 Place on the block diagram  Find on the Functions palette
pole radius constraint specifies the maximum pole radius for the new filter. The default is 0.99. A small pole radius constraint decreases the possibility of filter instability caused by finite precision effects. However, a small value of the pole radius constraint can adversely affect the potential sharpness of the group delay response. The valid values for pole radius constraint are within the range (0, 1]. This VI ignores the input and applies no constraint to the radius if a value is beyond the range.
integer offset? specifies whether the group delay offset between the group delay of the filter and predefined specifications is an integer or any real number. The default is TRUE. If you set integer offset? to FALSE, the group delay offset is any real number. Using an integer can slightly increase delay.
order specifies the filter order. The value of order must be greater than zero. The default is 10.
band specs specifies the group delay response you want for the filter, for one or more frequency bands.
freq specifies the frequency point.
group delay specifies the group delay you want for the frequency point.
weight defines the relative significance of the group delay you want. Increasing the value of weight adds precision to group delay for the frequency point.
error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
fs specifies the sampling frequency in hertz. The value must be greater than zero. The default is 1, which is the normalized sampling frequency.
filter out returns a new filter.
offset returns the group delay offset between the group delay of filter out and the group delay specified in band specs. The integer offset? input determines whether offset is an integer or a floating-point number.
error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.
status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

Example

Refer to the Arbitrary Group Delay Filter Design VI in the labview\examples\Digital Filter Design\Floating-Point Filters\Conventional directory for an example of using the DFD Arbitrary Group Delay Design VI.

 Open example  Browse related examples

previous page start next page