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info

Information about filter System object

Description

example

filtiInfo = info(rcfilter) obtains information about the specified filter System object™. The type of information returned by the function depends on the filter type and configuration.

filtInfo = info(rcfilter,infoType) obtains the amount of filter information as specified by infoType.

filtInfo = info(___,'Arithmetic',arithType) analyzes the filter System object based on the arithmetic specified in arithType. Specify this option with any of the input combinations from previous syntaxes.

For more input options, see the info function.

Examples

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Obtain short-format and long-format information about a raised cosine filter.

txfilter = comm.RaisedCosineTransmitFilter;
info(txfilter)
ans = 10x62 char array
    'Discrete-Time FIR Multirate Filter (real)                     '
    '-----------------------------------------                     '
    'Filter Structure      : Direct-Form FIR Polyphase Interpolator'
    'Interpolation Factor  : 8                                     '
    'Polyphase Length      : 11                                    '
    'Filter Length         : 81                                    '
    'Stable                : Yes                                   '
    'Linear Phase          : Yes (Type 1)                          '
    '                                                              '
    'Arithmetic            : double                                '

info(txfilter,'long')
ans = 17x62 char array
    'Discrete-Time FIR Multirate Filter (real)                     '
    '-----------------------------------------                     '
    'Filter Structure      : Direct-Form FIR Polyphase Interpolator'
    'Interpolation Factor  : 8                                     '
    'Polyphase Length      : 11                                    '
    'Filter Length         : 81                                    '
    'Stable                : Yes                                   '
    'Linear Phase          : Yes (Type 1)                          '
    '                                                              '
    'Arithmetic            : double                                '
    '                                                              '
    'Implementation Cost                                           '
    'Number of Multipliers            : 81                         '
    'Number of Adders                 : 73                         '
    'Number of States                 : 10                         '
    'Multiplications per Input Sample : 81                         '
    'Additions per Input Sample       : 73                         '

Input Arguments

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Input filter, specified as one of these of filter System objects.

Amount of filter information to display, specified as one of these values.

  • 'short' –– The function displays the basic filter information. This information is the same as the information output by info(rcfilter).

  • 'long' –– The function returns this information about the filter.

    • Specifications such as the filter structure and filter order.

    • Information about the design method and options.

    • Performance measurements, such as the passband cutoff or stopband attenuation, for the filter response.

    • Cost of implementing the filter in terms of operations required to apply the filter to data.

    When the filter uses fixed-point arithmetic, the function returns additional information about the filter. This information includes the arithmetic setting and details about the filter internals.

Data Types: char | string

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 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 coefficient data type is signed, has 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

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Filter information, returned as a character array.

  • When you set the infoType input to 'short', the function displays basic filter information.

  • When you set the infoType input to 'long', the function displays this.

    • Specifications such as the filter structure and filter order.

    • Information about the design method and options.

    • Performance measurements, such as the passband cutoff or stopband attenuation, for the filter response.

    • Cost of implementing the filter in terms of operations required to apply the filter to data.

When the filter uses fixed-point arithmetic, the function returns additional information about the filter. The information includes the arithmetic setting and details about the filter internals.

Introduced in R2013b