<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:'times new roman', 'new york', times, serif;font-size:12pt"><div>Yes, they are the same. Look at it this way:</div><div> </div><div>The directly modulated carrier is y(t) = cos(2*pi*430e6*t + phi(t)) where phi(t) is the PSK modulation. If a DSP is used to put the PSK on a low frequency carrier, say 1 KHz which is then up-converted to 430 MHz you will get:</div><div> </div><div>y(t) = cos(2*pi*429.990e6*t + 2*pi*1e3*t + phi(t)), which is the same.</div><div> </div><div>Chris Hansen, KQ6DW</div><div><br></div><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><br><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Andrew Rich <vk4tec@tech-software.net><br><b><span
style="font-weight: bold;">To:</span></b> TAPR APRS Mailing List <aprssig@tapr.org><br><b><span style="font-weight: bold;">Sent:</span></b> Saturday, September 12, 2009 8:09:59 PM<br><b><span style="font-weight: bold;">Subject:</span></b> [aprssig] Phase modulation question<br></font><br>
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<div><font size="2" face="Arial">I have a question </font></div>
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<div><font size="2" face="Arial">You get a carrier on 430 MHz and modulate it with a
an audio signal that changes phase eg PSK</font></div>
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<div><font size="2" face="Arial">You get a DSP to create a low level phase shifted
carrier and then up convert to 430 MHz and send that to air</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Are they different ?</font></div>
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<div><font size="2" face="Arial">----------------------------------------------------------<br>Andrew
Rich <br>Airways Technical Officer Grade 4<br>Surveillance - RADAR
ADS-B<br>Amateur Radio Callsign VK4TEC<br>email: <a rel="nofollow" ymailto="mailto:vk4tec@tech-software.net" target="_blank" href="mailto:vk4tec@tech-software.net">vk4tec@tech-software.net</a><br>web: <a rel="nofollow" target="_blank" href="http://www.tech-software.net">www.tech-software.net</a></font></div>
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