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Bug #3341

osmo-trx-lms RF Envelope FAIL on LimeSDR, but not on LimeSDR-mini

Added by laforge 2 months ago. Updated 8 days ago.

Status:
New
Priority:
High
Assignee:
Category:
LimeSDR
Target version:
-
Start date:
06/13/2018
Due date:
% Done:

0%

Estimated time:
Spec Reference:

Description

I'm observing a strange behavior when comparing the RF envelope of osmo-trx-lms on a LimeSDR and a LimeSDR-mini.

The LimeSDR-mini envelope is within spec. Specifically, the transmit power level is at full strength before the start of the next burst.

RF envelope on LimeSDR-mini RF envelope on LimeSDR-mini (zoom)

On the LimeSDR however, the next burst/timeslot starts too late, (or the slew rate is too low?):

RF envelope on LimeSDR RF envelope on LimeSDR (zoom)

This is using the exact same versions of LimeSuite (f1e5444496923890ad7d030abef9c224c37c46cf) and osmo-trx (70621b74844a6ea08d6da5f5b1e1835b9af91771). All I'm doing is swapping the hardware and re-starting osmo-trx-lms and osmo-bts.

It's very odd, and I currently have no clue of what might be going on here.

SCREEN1.BMP View SCREEN1.BMP 46.6 KB RF envelope on LimeSDR-mini laforge, 06/13/2018 01:42 PM
SCREEN2.BMP View SCREEN2.BMP 43.2 KB RF envelope on LimeSDR-mini (zoom) laforge, 06/13/2018 01:42 PM
SCREEN3.BMP View SCREEN3.BMP 48.3 KB RF envelope on LimeSDR laforge, 06/13/2018 01:42 PM
SCREEN4.BMP View SCREEN4.BMP 43.9 KB RF envelope on LimeSDR (zoom) laforge, 06/13/2018 01:42 PM
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Related issues

Related to OsmoTRX - Feature #2919: Native LimeSDR supportResolved2018-02-09

History

#1 Updated by laforge 2 months ago

#2 Updated by laforge about 1 month ago

  • Assignee set to roh

roh: please re-perform the LimeSDR (non-mini) tests using a LimeSDR that is clocked from the 10MHz reference of the E4406.

Please also try to modify the ts_offset found in the following line of the source code in osmo-trx/Transceiver52M/device/lms/LMSDevice.cpp:

ts_offset = static_cast<TIMESTAMP>(8.9e-5 * GSMRATE * tx_sps); /* time * sample_rate */

#3 Updated by laforge about 1 month ago

  • Priority changed from Normal to High

#4 Updated by laforge 8 days ago

ping?

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