DSP Blockset

Design Parameters of Classical Discrete-Time Filters.   All of the digital filter designs available in Digital FIR Filter Design and Digital IIR Filter Design blocks allow you to specify the order of the filter. In addition, depending on the specific design, you can specify one or more of the following frequency response parameters:

fn0	=	normalized cutoff or band edge frequency
fn1	=	normalized lower cutoff or band edge frequency
fn2	=	normalized upper cutoff or band edge frequency
fn	=	normalized cutoff or band edge frequency vector
mn	=	normalized magnitude vector
Rp	=	passband ripple in decibels
Rs	=	stopband attenuation in decibels

The table below shows the possible combinations.

	FIR	Butterworth	Chebyshev I	Chebyshev II	Elliptic
Lowpass	fn0	fn0	fn0, Rp	fn0, Rs	fn0, Rp, Rs
Highpass	fn0	fn0	fn0, Rp	fn0, Rs	fn0, Rp, Rs
Bandpass	fn1, fn2	fn1, fn2	fn1, fn2, Rp	fn1, fn2, Rs	fn1, fn2, Rp, Rs
Bandstop	fn1, fn2	fn1, fn2	fn1, fn2, Rp	fn1, fn2, Rs	fn1, fn2, Rp, Rs
Multiband	fn	n/a	n/a	n/a	n/a
Arbitrary Shape	fn, mn	n/a	n/a	n/a	n/a

The frequency response parameters available for the Digital FIR Filter Design block are determined by the option selected in the Filter type pop-up menu: Lowpass, Highpass, Bandpass, Bandstop, Multiband, or Arbitrary shape. The first four options are shared with the Digital IIR Filter Design block. The block dialog box adapts to show you the appropriate design parameters for whichever band configuration you select in the Filter type menu.

The four right columns in the above table show the various options presented in the Digital IIR Filter Design block's Design method pop-up menu: Butterworth, Chebyshev I, Chebyshev II, and Elliptic. Each column lists the filter specifications available in that design method for any band configuration that can be selected from the Filter type menu.

Designing Discrete-Time Classical IIR and FIR Filters

Specifying Classical Discrete-Time Filter Parameters