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Bandstop filter specification object

`D = fdesign.bandstop`

D = fdesign.bandstop(SPEC)

D = fdesign.bandstop(SPEC,specvalue1,specvalue2,...)

D = fdesign.bandstop(specvalue1,specvalue2,specvalue3,specvalue4,...

specvalue5,specvalue6,specvalue7)

D = fdesign.bandstop(...,Fs)

D = fdesign.bandstop(...,MAGUNITS)

`D = fdesign.bandstop`

constructs
a bandstop filter specification object `D`

, applying
default values for the properties `Fpass1`

, `Fstop1`

, `Fstop2`

, `Fpass2`

, `Apass1`

, `Astop1`

and `Apass2`

.

`D = fdesign.bandstop(SPEC)`

constructs
object `D`

and sets the `Specification`

property
to `SPEC`

. Entries in `SPEC`

represent
various filter response features, such as the filter order, that govern
the filter design. Valid entries for `SPEC`

are shown
below. These entries are not case sensitive.

Specification options marked with an asterisk require the DSP System Toolbox™ software.

`'Fp1,Fst1,Fst2,Fp2,Ap1,Ast,Ap2'`

(default spec)`'N,F3dB1,F3dB2'`

`'N,F3dB1,F3dB2,Ap'`

*`'N,F3dB1,F3dB2,Ap,Ast'`

*`'N,F3dB1,F3dB2,Ast'`

*`'N,F3dB1,F3dB2,BWp'`

*`'N,F3dB1,F3dB2,BWst'`

*`'N,Fc1,Fc2'`

`'N,Fc1,Fc2,Ap1,Ast,Ap2'`

`'N,Fp1,Fp2,Ap'`

`'N,Fp1,Fp2,Ap,Ast'`

`'N,Fp1,Fst1,Fst2,Fp2'`

`'N,Fp1,Fst1,Fst2,Fp2,C'`

*`'N,Fp1,Fst1,Fst2,Fp2,Ap'`

*`'N,Fst1,Fst2,Ast'`

`'Nb,Na,Fp1,Fst1,Fst2,Fp2'`

*

The filter specifications are defined as follows:

`Ap`

— amount of ripple allowed in the passband in decibels (the default units). Also called Apass.`Ap1`

— amount of ripple allowed in the pass band in decibels (the default units). Also called Apass1.`Ap2`

— amount of ripple allowed in the pass band in decibels (the default units). Also called Apass2.`Ast`

— attenuation in the first stopband in decibels (the default units). Also called Astop1.`BWp`

— bandwidth of the filter passband. Specified in normalized frequency units.`BWst`

— bandwidth of the filter stopband. Specified in normalized frequency units.`C`

— Constrained band flag. This enables you to specify passband ripple or stopband attenuation for fixed-order designs in one or two of the three bands.In the specification

`'N,Fp1,Fst1,Fst2,Fp2,C'`

, you cannot specify constraints simultaneously in both passbands and the stopband. You can specify constraints in any one or two bands.`F3dB1`

— cutoff frequency for the point 3 dB point below the passband value for the first cutoff.`F3dB2`

— cutoff frequency for the point 3 dB point below the passband value for the second cutoff.`Fc1`

— cutoff frequency for the point 6 dB point below the passband value for the first cutoff. (FIR filters)`Fc2`

— cutoff frequency for the point 6 dB point below the passband value for the second cutoff. (FIR filters)`Fp1`

— frequency at the start of the pass band. Also called Fpass1.`Fp2`

— frequency at the end of the pass band. Also called Fpass2.`Fst1`

— frequency at the end of the first stop band. Also called Fstop1.`Fst2`

— frequency at the start of the second stop band. Also called Fstop2.`N`

— filter order.`Na`

— denominator order for IIR filters.`Nb`

— numerator order for IIR filters.

Graphically, the filter specifications look similar to those shown in the following figure.

Regions between specification values like `Fp1`

and `Fst1`

are
transition regions where the filter response is not explicitly defined.

The filter design methods that apply to a bandstop filter specification
object change depending on the `Specification`

. Use `designmethods`

to determine which design
methods apply to an object and the `Specification`

property
value.

Use `designopts`

to determine
the design options for a given design method. Enter `help(D,METHOD)`

at
the MATLAB^{®} command line to obtain detailed help on the design
options for a given design method, `METHOD`

.

`D = fdesign.bandstop(SPEC,specvalue1,specvalue2,...)`

constructs
an object `D`

and sets its specifications at construction
time.

`D = fdesign.bandstop(specvalue1,specvalue2,specvalue3,specvalue4,...`

constructs
an object

specvalue5,specvalue6,specvalue7)`D`

with the default `Specification`

property,
using the values you provide in ```
specvalue1,specvalue2,specvalue3,specvalue4,specvalue5,
specvalue6
```

and `specvalue7`

.

`D = fdesign.bandstop(...,Fs)`

adds
the argument `Fs`

, specified in Hz to define the
sampling frequency. If you specify the sampling frequency as a trailing
scalar, all frequencies in the specifications are in Hz as well.

`D = fdesign.bandstop(...,MAGUNITS)`

specifies
the units for any magnitude specification you provide in the input
arguments. `MAGUNITS`

can be one of

`'linear'`

— specify the magnitude in linear units`'dB'`

— specify the magnitude in dB (decibels)`'squared'`

— specify the magnitude in power units

When you omit the `MAGUNITS`

argument, `fdesign`

assumes
that all magnitudes are in decibels. Note that `fdesign`

stores
all magnitude specifications in decibels (converting to decibels when
necessary) regardless of how you specify the magnitudes.

`fdesign`

| `fdesign.bandpass`

| `fdesign.highpass`

| `fdesign.lowpass`

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