设计一个巴特沃斯IIR滤波器。HD = DESIGN(D, 'butter')设计一个由FDESIGN对象D指定的Butterworth过滤器,并返回DFILT/MFILT对象HD。设计(d,…), 'SystemObject', true)使用System对象而不是DFILT/MFILT对象来实现过滤器HD。高清=设计(…, 'FilterStructure', STRUCTURE)返回一个结构为STRUCTURE的过滤器。STRUCTURE默认为'df2sos',可以是以下任何一种:'df1sos' 'df2sos' 'df1tsos' 'df2tsos' 'cascadeallpass' 'cascadewdfallpass'列出的部分结构可能不被System对象过滤器支持。金宝app键入validstructures(D, 'butter', 'SystemObject', true)来获得一个由System对象支持的结构列表。金宝app高清=设计(…,“SOSScaleNorm”,NORM)设计了一个SOS过滤器,并使用P-Norm NORM缩放系数。 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 - Design a lowpass Butterworth filter in the DF2TSOS structure. h = fdesign.lowpass('N,F3dB'); Hd = design(h, 'butter', 'FilterStructure', 'df2tsos');