https://wiki.opendigitalradio.org/index.php?title=USRP_B200_Measurements&feed=atom&action=historyUSRP B200 Measurements - Revision history2024-03-28T12:42:23ZRevision history for this page on the wikiMediaWiki 1.19.20+dfsg-0+deb7u3https://wiki.opendigitalradio.org/index.php?title=USRP_B200_Measurements&diff=1126&oldid=prevHb9egm: /* Measurements of the USRP B200 */2014-04-15T17:23:17Z<p><span dir="auto"><span class="autocomment">Measurements of the USRP B200</span></span></p>
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</tr></table>Hb9egmhttps://wiki.opendigitalradio.org/index.php?title=USRP_B200_Measurements&diff=1117&oldid=prevHb9egm: Created page with "==Measurements of the USRP B200== ===Setup=== The ODR-mmbTools have been used to generate a DAB transmission with the B200, which was connected to a R&S spectrum analys..."2014-04-08T17:07:04Z<p>Created page with "==Measurements of the USRP B200== ===Setup=== The <a href="/ODR-mmbTools" class="mw-redirect" title="ODR-mmbTools">ODR-mmbTools</a> have been used to generate a DAB transmission with the B200, which was connected to a R&S spectrum analys..."</p>
<p><b>New page</b></p><div>==Measurements of the USRP B200==<br />
<br />
<br />
===Setup===<br />
<br />
The [[ODR-mmbTools]] have been used to generate a DAB transmission<br />
with the B200, which was connected to a R&S spectrum analyser.<br />
<br />
Versions used:<br />
* ODR-DabMux v0.6.0<br />
* ODR-DabMod v0.4.3<br />
* UHD release_003_007_000<br />
<br />
The USRP B200 was connected over USB2.0 to a thinkpad T420,<br />
and was externally powered using a 6V laboratory power source.<br />
<br />
===Measurements===<br />
<br />
<br />
The meas-parameters.csv file describes the dabmod parameters<br />
<br />
* master_clock_rate<br />
* sample rate<br />
* gain mode<br />
* digital gain<br />
* analog TX gain<br />
<br />
used for each generated image.<br />
<br />
===Observations===<br />
<br />
*digital gain* of 1.0 or *gain mode* 0 lead to spurious signals.<br />
This can be due to clipping in the digital domain.<br />
<br />
Some *master_clock_rate* settings are better than others. The decimation<br />
factor N = master_clock_rate/sample rate is the important parameters.<br />
<br />
For N = 5 (10240000), 6 (12288000), 10 (20480000) and 15 (30720000), we see ugly shoulders next<br />
to the transmission.<br />
<br />
For N = 8 (16384000), 12 (24576000) and 16 (32768000) the ugly shoulders are not present. N = 4 and below doesn't work.<br />
<br />
The analog *TX gain* has to be above 35, but at about 80 we start seeing the shoulders increase. The best value<br />
for this parameter has to be found experimentally, in a complete transmitter setup, but is likely to be between 70 and<br />
85.<br />
<br />
===Conclusion===<br />
<br />
<br />
The best settings seem to correspond to<br />
<br />
* gain mode = 2<br />
* master_clock_rate = 32768000<br />
* native DAB sample rate of 2048000<br />
* digital gain = 0.8<br />
* tx gain at most 80<br />
<br />
A real world will certainly offer us more insight into these parameters.</div>Hb9egm