<html><head></head><body><div style="color:#000; background-color:#fff; font-family:verdana, helvetica, sans-serif;font-size:13px"><div><span></span></div><div></div><div id="yui_3_16_0_1_1446821725447_5162">Hi all,</div><div id="yui_3_16_0_1_1446821725447_5220"><br></div><div id="yui_3_16_0_1_1446821725447_5221">Is anyone using Matlab for computer based algebraic computation? </div><div id="yui_3_16_0_1_1446821725447_5219"> </div><div class="signature" id="yui_3_16_0_1_1446821725447_5196"><div id="yui_3_16_0_1_1446821725447_5218"><font size="2">Sincerely, <br> </font></div><div id="yui_3_16_0_1_1446821725447_5209"><font id="yui_3_16_0_1_1446821725447_5208" size="2">Chris Juried <br>Audio Engineering Society (AES) <var id="yui-ie-cursor"></var>Member <br>InfoComm-Recognized AV Technologist<br><a id="yui_3_16_0_1_1446821725447_5207" href="http://www.juriedengineering.com/" target="_blank" rel="nofollow">http://www.juriedengineering.com</a> </font></div><div id="yui_3_16_0_1_1446821725447_5195"><font id="yui_3_16_0_1_1446821725447_5205" size="3"><font id="yui_3_16_0_1_1446821725447_5204" size="2"><br></font>This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.</font><br></div></div><br> <div id="yui_3_16_0_1_1446821725447_5224" style="font-family: verdana, helvetica, sans-serif; font-size: 13px;"> <div id="yui_3_16_0_1_1446821725447_5223" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1446821725447_5222" dir="ltr"> <hr size="1"> <font id="yui_3_16_0_1_1446821725447_5225" face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> Neil Johnson <neil.johnson71@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> Phil Macphail <phil.macphail@liivatera.com> <br><b><span style="font-weight: bold;">Cc:</span></b> synthdiy diy <synth-diy@dropmix.xs4all.nl> <br> <b><span style="font-weight: bold;">Sent:</span></b> Tuesday, November 3, 2015 12:44 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [sdiy] Passive filters and impedances<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_1_1446821725447_5228"><br><div id="yiv3012463511"><div id="yui_3_16_0_1_1446821725447_5227"><div id="yui_3_16_0_1_1446821725447_5226" dir="ltr">HI Phil,<div class="qtdSeparateBR"><br><br></div><div class="yiv3012463511yqt6946304331" id="yiv3012463511yqtfd53237"><br clear="none"><br clear="none"></div><div class="yiv3012463511gmail_extra" id="yui_3_16_0_1_1446821725447_5231"><div class="yiv3012463511gmail_quote" id="yui_3_16_0_1_1446821725447_5230"><blockquote class="yiv3012463511gmail_quote" id="yui_3_16_0_1_1446821725447_5229" style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div class="yiv3012463511yqt6946304331" id="yiv3012463511yqtfd74901">An alternative that could be easier to get started with would be to use a series of ABCD matrices. That way you can solve for any number of stages too.</div><br clear="none"></blockquote><div id="yui_3_16_0_1_1446821725447_5259"><br clear="none"></div><div id="yui_3_16_0_1_1446821725447_5258">Thanks for stirring up some ancient memories!<br clear="none"><br clear="none"></div><div id="yui_3_16_0_1_1446821725447_5232">After a quick refresher, e.g., <a href="http://www.engr.sjsu.edu/rkwok/EE172/Microwave_Network.pdf" target="_blank" rel="nofollow" shape="rect">http://www.engr.sjsu.edu/rkwok/EE172/Microwave_Network.pdf</a><br clear="none"><br clear="none"></div></div>and some fun with wxmaxima it is actually quite easy to bash in the equation for the filter, and then you can flip it around to work out the transfer function. In this case the filter is represented as:<br clear="none"><br clear="none">matrix([1,R1],[0,1]).matrix([1,0],[%i*w*C1,1]).matrix([1,R2],[0,1]).matrix([1,0],[%i*w*C2,1]).matrix([1,R3],[0,1]).matrix([1,0],[%i*w*C3,1]).matrix([1,0],[1/Rimp,1]);<br clear="none"><br clear="none"></div><div class="yiv3012463511gmail_extra">and turns into something that has quite a few brackets, and as Murphy would have it the A term has the most.<br clear="none"><br clear="none"></div><div class="yiv3012463511gmail_extra">Cheers,<br clear="none"></div><div class="yiv3012463511gmail_extra">Neil <br clear="none"></div><div class="yiv3012463511gmail_extra"><div class="yiv3012463511gmail_signature">--<br clear="none"><a href="http://www.njohnson.co.uk/" target="_blank" rel="nofollow" shape="rect">http://www.njohnson.co.uk</a><div class="yiv3012463511yqt6946304331" id="yiv3012463511yqtfd34784"><br clear="none"><br clear="none"></div></div><div class="yiv3012463511yqt6946304331" id="yiv3012463511yqtfd93833">
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