isreal

Verify that discrete-time filter System object is real

Syntax

flag = isreal(sysobj)

Description

flag = isreal(sysobj) determines if the filter coefficients are real. If the filter coefficients are real, isreal returns a logical 1. If the filter coefficients are complex, isreal returns a logical 0. Complex filters have one or more coefficients with nonzero imaginary parts.

Examples

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Check if Filter Coefficients Are Real

Open Live Script

Create a dsp.BiquadFilter System object™. Pass a fixed-point input to the object. Test the coefficients of the fixed-point filter to see if they are strictly real.

d = fdesign.lowpass('n,fp,ap,ast',5,0.4,0.5,20);
biquadFilter = design(d,'ellip','SystemObject',true);
IsRealBefore = isreal(biquadFilter)

IsRealBefore = logical
   1

Pass a fixed-point input to the object.

fiInput = fi(randn(1000,2),1,32,16);
fiOutput = biquadFilter(fiInput);
IsRealAfter = isreal(biquadFilter)

IsRealAfter = logical
   1

The isreal function returns a value of 1, indicating that the filter coefficients are real.

Input Arguments

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Output Arguments

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`flag` — Flag to determine whether filter coefficients are real
`1` | `0`

Flag to determine whether the filter coefficients are real, returned as a logical scalar. If the filter coefficients are real, isreal returns a logical 1, else it returns a logical 0.

Data Types: logical