<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Here is David’s message including the gifs. Sorry about the problems.<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">Begin forwarded message:</div><br class="Apple-interchange-newline"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><b class="" style="font-family: "Times New Roman"; font-size: 12pt;"><font size="2" face="Tahoma" class=""><span style="font-size: 10pt;" class="">From:</span></font></b><font size="2" face="Tahoma" class=""><span style="font-size: 10pt;" class=""> David G Dixon [<a href="mailto:dixon@mail.ubc.ca" style="color: blue;" class="">mailto:dixon@mail.ubc.ca</a>] </span></font></div><div class=""><o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="State" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place" class=""><o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City" class=""><div class="Section1" style="page: Section1;"><div class=""><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" face="Tahoma" class=""><span style="font-size: 10pt; font-family: Tahoma;" class=""><b class=""><span style="font-weight: bold;" class="">Sent:</span></b><span class="Apple-converted-space"> </span>Tuesday, April 21, 2020 1:25 PM<br class=""><b class=""><span style="font-weight: bold;" class="">To:</span></b><span class="Apple-converted-space"> </span>'Donald Tillman'; 'Renจฆ Schmitz'<br class=""><b class=""><span style="font-weight: bold;" class="">Cc:</span></b><span class="Apple-converted-space"> </span>'<a href="mailto:synth-diy@synth-diy.org" style="color: blue; text-decoration: underline;" class="">synth-diy@synth-diy.org</a>'<br class=""><b class=""><span style="font-weight: bold;" class="">Subject:</span></b><span class="Apple-converted-space"> </span>RE: [sdiy] An Improved Sine Shaper Circuit</span></font><font face="SimSun" class=""><span style="font-family: SimSun;" class=""><o:p class=""></o:p></span></font></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="3" face="Times New Roman" class=""><span style="font-size: 12pt;" class=""><o:p class=""> </o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class="">I just simulated the Thomas Henry transistor-pair sine shaper, and compared the output to a 90-degree phase shifted pure sine wave of equal amplitude. It is virtually impossible to tell the two apart จC THD = 0.57% -- light blue is the pure one, orange is the shaped one.<o:p class=""></o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><o:p class=""> </o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><img id="_x0000_i1026" class="" apple-inline="yes" src="cid:image002.gif@01D617DE.BA800920"><o:p class=""></o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><o:p class=""> </o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class="">Hereกฏs the sine shaper circuit Iกฏm simulating จC this is exactly the circuit I build into all my VCOs (transistors are 2N3904, opamp is TL07X จC the 11k resistors get me closer to 10Vpp than 10k):<o:p class=""></o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><o:p class=""> </o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><img id="_x0000_i1027" class="" apple-inline="yes" src="cid:image003.gif@01D617DE.8070E830"><o:p class=""></o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><o:p class=""> </o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class="">In what way does the output of the diff pair not look like a sine wave?<o:p class=""></o:p></span></font></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";" class=""><font size="2" color="navy" face="Arial" class=""><span style="font-size: 10pt; font-family: Arial; color: navy;" class=""><o:p class=""> </o:p></span></font></div><div class=""><div class="MsoNormal" align="center" style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; text-align: center;"><font size="3" face="Times New Roman" class=""><span style="font-size: 12pt;" class=""></span></font></div></div></div></o:smarttagtype></o:smarttagtype></o:smarttagtype></div></blockquote></div><br class=""><div class=""><br class=""></div></body></html>