Chebyshev Type I filter using specification object
hd = design(d,'cheby1')
hd = design(d,'cheby1',designoption,value,designoption,
hd = design(d,'cheby1') designs a type I Chebyshev IIR digital filter using the specifications supplied in the object d. Depending on the filter specification object, cheby1 may or may not be a valid design. Use designmethods with the filter specification object to determine if a Chebyshev type I filter design is possible.
To determine the available design options, use designopts with the specification object and the design method as input arguments as shown.
For complete help about using cheby1, refer to the command line help system. For example, to get specific information about using cheby1 with d, the specification object, enter the following at the MATLAB prompt.
These examples use filter specification objects to construct Chebyshev type I filters. In the first example, you use the matchexactly option to ensure the performance of the filter in the passband.
d = fdesign.lowpass; designopts(d,'cheby1'); hd = design(d,'cheby1','matchexactly','passband');
Specify the filter order, passband edge frequency, and the passband ripple to get the filter exactly as required.
d = fdesign.highpass('n,fp,ap',7,20,.4,50); hd = design(d,'cheby1');
Use fvtool to view the resulting filter.
By design, cheby1 returns filters that use second-order sections (SOS). For many applications, and for most fixed-point applications, SOS filters are particularly well-suited.