<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
Hi Tom,<br>
<br>
I think Phil already answered the question. From the standpoint of
another software developer, I can confirm that I have seen this too
as I've developed new code. I just take the pragmatic position of
flipping I/Q and moving on. I'm not sure I've ever even mentioned
it to the firmware developers or asked about the history. The
history that Phil provided is interesting.<br>
<br>
73,<br>
Warren NR0V<br>
<br>
<div class="moz-cite-prefix">On 3/13/2014 3:26 AM, Tom McDermott
wrote:<br>
</div>
<blockquote
cite="mid:1394706407.65767.YahooMailNeo@web121406.mail.ne1.yahoo.com"
type="cite">
<pre wrap="">***** High Performance Software Defined Radio Discussion List *****
</pre>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<div style="color:#000; background-color:#fff;
font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial,
Lucida Grande, sans-serif;font-size:12pt">
<div><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">HI,</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">In playing with some gnuradio sources, I am getting a
baseband frequency reversal going through Hermes.</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">This using the definitions for I and Q in the HPSDR
USB protocol document (ver 1.43).<br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">That is - a downward frequency chirping IQ baseband
signal into transmit causes an upward chirping</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">IQ baseband signal at the receive output.</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">It appears that the transmit I & Q side is doing
the reversal, while the receiver seems to be normal, by
testing this with an external SSB receiver, and by using
various gnuradio instrumentation.<br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">In looking through my own code that formats I & Q
into the transmit frame, I cannot seem to find any</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">deviation from the protocol specification (rev
1.43). Do I have a bug in my code, or is there a known </div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">issue with Hermes that causes the frequency sign
inversion on transmit?</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;">-- Tom, N5EG</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,sans-serif; background-color: transparent; font-style:
normal;"><br>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
HPSDR Discussion List
To post msg: <a class="moz-txt-link-abbreviated" href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a>
Subscription help: <a class="moz-txt-link-freetext" href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a>
HPSDR web page: <a class="moz-txt-link-freetext" href="http://openhpsdr.org">http://openhpsdr.org</a>
Archives: <a class="moz-txt-link-freetext" href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a></pre>
</blockquote>
<br>
</body>
</html>