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<DIV>The close in phase noise of the 122.88MHz VCXO is reduced within the
bandwidth of the loop filter due to the effects of the internal/external 10MHz
reference. </DIV>
<DIV> </DIV>
<DIV>This is the reason why the close in phase noise specification is better
than that of the master oscillator alone.</DIV>
<DIV> </DIV>
<DIV>73 Phil...VK6PH </DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=brian@lloyd.com
href="mailto:brian@lloyd.com">Brian Lloyd</A> </DIV>
<DIV><B>Sent:</B> Saturday, December 14, 2013 2:06 AM</DIV>
<DIV><B>To:</B> <A title=dc6ny@gmx.de href="mailto:dc6ny@gmx.de">Helmut,
DC6NY</A> </DIV>
<DIV><B>Cc:</B> <A title=hpsdr@lists.openhpsdr.org
href="mailto:hpsdr@lists.openhpsdr.org">hpsdr@lists.openhpsdr.org</A> </DIV>
<DIV><B>Subject:</B> Re: [hpsdr] New clock oscillator for
OpenHPSDR?</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>*****
High Performance Software Defined Radio Discussion List *****<BR><BR>
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<DIV class=gmail_quote>On Fri, Dec 13, 2013 at 10:52 AM, Helmut, DC6NY <SPAN
dir=ltr><<A href="mailto:dc6ny@gmx.de"
target=_blank>dc6ny@gmx.de</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV class=im>***** High Performance Software Defined Radio Discussion List
*****<BR><BR></DIV>Hi Kjell.<BR><BR>Thanks for information, but I see no
direct chance for any substitution in<BR>this 5V sine wave application. On the
10 MHz level phase noise hasn't been<BR>an issue and concerning to the
sampling frequency 122,88 Mhz I'm not sure<BR>that the approx. 10 dB better
phase noise can improve SFDR dramatically. But<BR>it's interesting that a lot
of suppliers meanwhile discover phase noise a<BR>determining factor of
total system's performance.<BR></BLOCKQUOTE>
<DIV> </DIV>
<DIV>Please correct me if I am wrong, but the loop filter at the output of the
phase comparator prior to the control input at the 122.88MHz master oscillator
effectively attenuates the phase noise from the 10MHz reference thus preventing
it from affecting system performance. I would expect the native phase noise of
the 122.88MHz master oscillator to dominate the phase noise performance of the
system. This would mean that a low-phase-noise reference (GPSDO or Rb) is not
that necessary.</DIV>
<DIV> </DIV>
<DIV>Am I correct?</DIV>
<DIV> </DIV></DIV>-- <BR>
<DIV dir=ltr>Brian Lloyd, WB6RQN/J79BPL <IMG
src="http://www.catb.org/hacker-emblem/glider.png"><BR>706 Flightline
Drive<BR>Spring Branch, TX 78070<BR><A href="mailto:brian@lloyd.com"
target=_blank>brian@lloyd.com</A><BR><SPAN><SPAN id=gc-number-91
title="Call with Google Voice"
class=gc-cs-link>+1.916.877.5067</SPAN></SPAN></DIV></DIV></DIV>
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