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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Sample twice as fast and that sample will
be there.<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>

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<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;color:windowtext'>

<hr size=2 width="100%" align=center tabindex=-1>

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<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold'>From:</span></font></b><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:windowtext'> David PICARD [mailto:d.picard@opgc.univ-bpclermont.fr] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, May 10, 2011 2:42
AM<br>
<b><span style='font-weight:bold'>To:</span></b> users@lists.scilab.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [scilab-Users]
z^(-1/2) half cycle delay in discrete time</span></font><font color=black><span
style='color:windowtext'><o:p></o:p></span></font></p>

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<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>

<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'>z^-1 is the  value of the system 1 sampling
period in the past. But as sampling is discrete, does it make sense to
reference a value that is between 2 samples, but that does not exist in your
model, since, by definition, it is not sampled ?<br>
<br>
<br>
Le 09/05/2011 19:27, Dean Parsons a écrit : <o:p></o:p></span></font></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>Hello,</span></font></b></strong><o:p></o:p></p>

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<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>I want to add a half cycle delay to a discrete time
transfer function by multiplying the transfer function by z^(-0.5). It seems
Scilab doesn't allow non-integer exponents with the discrete time variable z:</span></font></b></strong><o:p></o:p></p>

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<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>-->z=poly(0,"z");</span></font></b></strong><b><font
size=4><span style='font-size:13.5pt;font-weight:bold'><br>
<strong><b><font face="Times New Roman"> </font></b></strong><br>
<strong><b><font face="Times New Roman">-->a = z^(-0.5);</font></b></strong><br>
<strong><b><font face="Times New Roman">            
!--error 30 </font></b></strong><br>
<strong><b><font face="Times New Roman">Invalid exponent.</font></b></strong></span></font></b><o:p></o:p></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>Is there a work around for this? Is
there another way to create the discrete time delay z^(-1/2)?</span></font></b></strong><o:p></o:p></p>

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<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>Thank you for your help with this.</span></font></b></strong><o:p></o:p></p>

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<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>

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<p class=MsoNormal><strong><b><font size=4 color=black face="Times New Roman"><span
style='font-size:13.5pt'>Dean Parsons</span></font></b></strong><o:p></o:p></p>

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