设计一个切比雪夫型iir滤波器设计。高清=设计(D, cheby1)设计一个切比雪夫型过滤器D FDESIGN指定的对象,并返回DFILT / HD MFILT对象。高清=设计(D,…,“SystemObject”,true) implements the filter, HD, using a System object instead of a DFILT/MFILT object. HD = DESIGN(..., 'FilterStructure', STRUCTURE) returns a filter with the structure STRUCTURE. STRUCTURE is 'df2sos' by default and can be any of the following: 'df1sos' 'df2sos' 'df1tsos' 'df2tsos' 'cascadeallpass' 'cascadewdfallpass' Some of the listed structures may not be supported by System object filters. Type validstructures(D, 'cheby1', 'SystemObject', true) to get a list of structures supported by System objects. HD = DESIGN(..., 'MatchExactly', MATCH) designs a Chebyshev type I filter and matches the frequency and magnitude specification for the band MATCH exactly. The other band will exceed the specification. MATCH can be 'stopband' or 'passband' and is 'passband' by default. HD = DESIGN(..., 'SOSScaleNorm', NORM) designs an SOS filter and scales the coefficients using the P-Norm NORM. NORM can be either a discrete-time-domain norm or a frequency-domain norm. Valid time-domain norms are 'l1','l2', and 'linf'. Valid frequency-domain norms are 'L1','L2', and 'Linf'. Note that L2-norm is equal to l2-norm (Parseval's theorem) but the same is not true for other norms. The different norms can be ordered in terms of how stringent they are as follows: 'l1' >= 'Linf' >= 'L2' = 'l2' >= 'L1' >= 'linf'. Using the most stringent scaling, 'l1', the filter is the least prone to overflow, but also has the worst signal-to-noise ratio. Linf-scaling is the most commonly used scaling in practice. Scaling is turned off by default, which is equivalent to setting SOSScaleNorm = ''. HD = DESIGN(..., 'SOSScaleOpts', OPTS) designs an SOS filter and scales the coefficients using an FDOPTS.SOSSCALING object OPTS. Scaling options are: Property Default Description/Valid values --------- ------- ------------------------ 'sosReorder' 'auto' Reorder section prior to scaling. {'auto','none','up','down','lowpass', 'highpass','bandpass','bandstop'} 'MaxNumerator' 2 Maximum value for numerator coefficients 'NumeratorConstraint' 'none' {'none', 'unit', 'normalize','po2'} 'OverflowMode' 'wrap' {'wrap','saturate'} 'ScaleValueConstraint' 'unit' {'unit','none','po2'} 'MaxScaleValue' 'Not used' Maximum value for scale values When sosReorder is set to 'auto', the sections will be automatically reordered depending on the response type of the design (lowpass, highpass, etc.). Note that 'MaxScaleValue' will only be used when 'ScaleValueConstraint' is set to something other than 'unit'. If 'MaxScaleValue' is set to a number, the 'ScaleValueConstraint' will be changed to 'none'. Further, if SOSScaleNorm is off (as it is by default), then all the SOSScaleOpts will be ignored. For more information about P-Norm and scaling options see help for DFILT\SCALE. % Example #1 - Compare passband and stopband MatchExactly. h = fdesign.lowpass('Fp,Fst,Ap,Ast', .1, .3, 1, 60); Hd = design(h, 'cheby1', 'MatchExactly', 'passband'); Hd(2) = design(h, 'cheby1', 'MatchExactly', 'stopband'); % Compare the passband edges in FVTool. fvtool(Hd); axis([.09 .11 -2 0]);