Dear community
I've been trying to make a fully synchronous multi USRP transmitter in GNURadio v3.8.2.0 and UHD v3.15.0.0.
In order to have a common clock and time between 2 USRPs, an octoclock is also used.
when trying to run a flowgraph which consists one multi_usrp sink block that is connected to a signal source in GNURadio and running the flowgrapth I get this error:
Executing: /usr/bin/python3 -u
/home/.../Documents/gnuradio-tests/octoclock_test.py
[INFO] [UHD] linux; GNU C++ version 9.3.0; Boost_107100;
UHD_3.15.0.HEAD-0-gaea0e2de
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 7972 bytes.
[WARNING] [X300] For the 192.168.30.2 connection, UHD recommends
a receive frame size of at least 8000 for best
performance, but your configuration will only allow 7972.This
may negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size
argument.
[INFO] [X300] Maximum frame size: 7972 bytes.
[WARNING] [X300] For the 192.168.50.2 connection, UHD recommends
a receive frame size of at least 8000 for best
performance, but your configuration will only allow 7972.This
may negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size
argument.
[INFO] [X300] Radio 1x clock: 200 MHz
[INFO] [0/DmaFIFO_0] Initializing block control (NOC ID:
0xF1F0D00000000000)
[INFO] [X300] Radio 1x clock: 200 MHz
[INFO] [0/DmaFIFO_0] BIST passed (Throughput: 1308 MB/s)
[INFO] [0/DmaFIFO_0] BIST passed (Throughput: 1312 MB/s)
[INFO] [1/DmaFIFO_0] Initializing block control (NOC ID:
0xF1F0D00000000000)
[INFO] [1/DmaFIFO_0] BIST passed (Throughput: 1316 MB/s)
[INFO] [1/DmaFIFO_0] BIST passed (Throughput: 1304 MB/s)
[INFO] [0/Radio_0] Initializing block control (NOC ID:
0x12AD100000000001)
[INFO] [1/Radio_0] Initializing block control (NOC ID:
0x12AD100000000001)
[INFO] [0/Radio_1] Initializing block control (NOC ID:
0x12AD100000000001)
[INFO] [1/Radio_1] Initializing block control (NOC ID:
0x12AD100000000001)
[INFO] [0/DDC_0] Initializing block control (NOC ID:
0xDDC0000000000000)
[INFO] [1/DDC_0] Initializing block control (NOC ID:
0xDDC0000000000000)
[INFO] [0/DDC_1] Initializing block control (NOC ID:
0xDDC0000000000000)
[INFO] [1/DDC_1] Initializing block control (NOC ID:
0xDDC0000000000000)
[INFO] [0/DUC_0] Initializing block control (NOC ID:
0xD0C0000000000000)
[INFO] [1/DUC_0] Initializing block control (NOC ID:
0xD0C0000000000000)
[INFO] [0/DUC_1] Initializing block control (NOC ID:
0xD0C0000000000000)
[INFO] [1/DUC_1] Initializing block control (NOC ID:
0xD0C0000000000000)
[INFO] [MULTI_USRP] 1) catch time transition at pps edge
[INFO] [MULTI_USRP] 2) set times next pps (synchronously)
thread[thread-per-block[6]: <block usrp_sink(1)>]:
RuntimeError: Multiple sampling rates downstream of TX
Terminator 0: RuntimeError: Node 0/DUC_0 specifies 1e+06, node
0/DUC_1 specifies 390625.
I've seen this error as an unresolved bug in the UHD git repo where you can find details about it in the following link:
https://github.com/EttusResearch/uhd/issues/367
But I really wonder how other manage to do so????? since this is a very basic and common configuration for make a multi USRP MIMO setup and I cant believe if there is no other solution to do so.
Attached you can find the flowgraph that I run.
Best regards.
Armin
Ghani
Research Engineer | Communication Systems Division (CSD)
aghani@cttc.es | +34 93 645 29 08 (2143)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Av. Carl Friedrich Gauss, 7 - Edifici B4 - PMT
08860 - Castelldefels (Barcelona, Spain)
