Main Content

isallpass

Verify that discrete-time filter System object is allpass

collapse all in page

Syntax

flag = isallpass(sysobj)
flag = isallpass(sysobj,tol)
flag = isallpass(___,Arithmetic=arithType)

Description

flag = isallpass(sysobj) returns true if the filter System object™ is allpass.

example

flag = isallpass(sysobj,tol) uses the tolerance tol to determine when two numbers are close enough to be considered equal.

flag = isallpass(___,Arithmetic=arithType) analyzes the filter System object based on the arithmetic specified in arithType, using either of the previous syntaxes.

For more input options, see isallpass in Signal Processing Toolbox™.

Examples

collapse all

Open Live Script

Create an allpass filter using the dsp.AllpassFilter object.

apass = dsp.AllpassFilter
apass = 
  dsp.AllpassFilter with properties:

                    Structure: 'Minimum multiplier'
          AllpassCoefficients: [-0.7071 0.5000]
    TrailingFirstOrderSection: false

Verify that the filter is an allpass filter by visualizing the magnitude response.

filterAnalyzer(apass)

Now verify that the filter is an allpass filter using the isallpass function.

isallpass(apass)
ans = logical
   1

Input Arguments

collapse all

Input filter, specified as one of the following filter System objects:

Tolerance value to determine when two numbers are close enough to be considered equal, specified as a positive scalar. If not specified, tol, defaults to eps^(2/3). Specifying a tolerance may be most helpful in fixed-point allpass filters.

Arithmetic used in the filter analysis, specified as 'double', 'single', or 'Fixed'. When the arithmetic input is not specified and the filter System object is unlocked, the analysis tool assumes a double-precision filter. When the arithmetic input is not specified and the System object is locked, the function performs the analysis based on the data type of the locked input.

The 'Fixed' value applies to filter System objects with fixed-point properties only.

When the 'Arithmetic' input argument is specified as 'Fixed' and the filter object has the data type of the coefficients set to 'Same word length as input', the arithmetic analysis depends on whether the System object is unlocked or locked.

  • unlocked –– The analysis object function cannot determine the coefficients data type. The function assumes that the coefficients data type is signed, has a 16-bit word length, and is auto scaled. The function performs fixed-point analysis based on this assumption.

  • locked –– When the input data type is 'double' or 'single', the analysis object function cannot determine the coefficients data type. The function assumes that the data type of the coefficients is signed, has a 16-bit word length, and is auto scaled. The function performs fixed-point analysis based on this assumption.

To check if the System object is locked or unlocked, use the isLocked function.

When the arithmetic input is specified as 'Fixed' and the filter object has the data type of the coefficients set to a custom numeric type, the object function performs fixed-point analysis based on the custom numeric data type.

Output Arguments

collapse all

Flag to determine if the filter is allpass, returned as a logical:

  • 1 –– Filter is allpass.

  • 0 –– Filter is not allpass.

Data Types: logical

Version History

Introduced in R2013a

expand all

See Also