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<span style="font-size: 12pt;"><o:p style=""><font color="#ff0000" face="Arial, sans-serif"><span style="background-color: rgb(250, 250, 250);"> </span></font><font color="#000000" face="Calibri, sans-serif"> </font></o:p></span></p>
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<span style="font-size:12.0pt">David –<o:p> </o:p></span></p>
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<span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<span style="font-size:12.0pt">The filter design problem addressed by Parks-McClellan (etc.) is not the Chebyshev problem, but rather a digital FIR version of the analog CAUER filter (sometimes called an elliptic filter); being “Chebyshev” in both the passband
and the stopband (also allowing “transition bands”). <span style="mso-spacerun:yes">
</span>Please do read </span><span style="font-size:12.0pt;font-family:"Arial",sans-serif">my “A New Simplified Equiripple Design Algorithm for FIR Filters” Electronotes 175 August 1989, pp 3-50.<span style="mso-spacerun:yes">
</span>The approximation (to a desired response) involves the same math whether you are talking amplitude response or phase error or whatever.<o:p> </o:p></span></p>
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<span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<span style="font-size:12.0pt">I understand what you did and for the third time state that there is nothing wrong with what you did.<o:p> </o:p></span></p>
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<span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<span style="font-size:12.0pt">But you have avoided my repeated questions about what the error plot looks like if you do fewer iterations.
<span style="mso-spacerun:yes"> </span>[ Neither have you commented your program or (despite saying there were several errors along the way) provided a full corrected copy. ]
<o:p> </o:p></span></p>
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<span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<span style="font-size:12.0pt">-Bernie<o:p> </o:p></span></p>
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