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From: | Guy Holtzman |
Subject: | Re: [Discuss-gnuradio] external clock issue with B100 + WBX |
Date: | Mon, 3 Jun 2013 13:59:27 +0300 |
On 06/02/2013 02:49 PM, Guy Holtzman wrote:Look at the 1PPS and 10MHz signals on the scope with them connected to the B100 -- are the levels still in range for the input spec?:_______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradioRegards, GuyI am using the latest version of GNU Radiowhenever I set the clock source for default, I get a carrier, but it is shifted a few 100s of hertz from the wanted signal and it changes every a few 100s of hertz (it is not constant)whenever I set the clock source to external on the receiver side, instead of getting a carrier, I get a distorted signal: the I and Q are not constant envelope, as they should be.tested the output with WX GUI FFT Sink on the Rx sidesync: unknown 1ppstime source: externalclock source: externalI configured both devices for:for my test I transmit from one USRP B100, and receive from the other USRP.it has a 10MHZ 1Vrms 50 ohm sine and 1pps outputs. I have tested it with a scope to see if its stable.the source is a rubidium standard source referenceI have two USRP B100 and I am trying to sync themfor that I have connected them both to reference and 1pps from the same source
I didn't see any warning or error message when disconnecting the 10MHz clock ref.
I did see an error message when I disconnected the 1pps ref.is this a known problem? is this expected? if not, what am I doing wrong?
I am adding the grc fileshere is the log (it seems fine, and look identical for Tx and Rx):
Generating: "/home/guy/Documents/top_block.py"
Executing: "/home/guy/Documents/top_block.py"
linux; GNU C++ version 4.6.3; Boost_104800; UHD_003.005.003-78-g49a4929b
-- USRP-B100 clock control: 10
-- r_counter: 2
-- a_counter: 0
-- b_counter: 20
-- prescaler: 8
-- vco_divider: 5
-- chan_divider: 5
-- vco_rate: 1600.000000MHz
-- chan_rate: 320.000000MHz
-- out_rate: 64.000000MHz
--
-- 1) catch time transition at pps edge
-- 2) set times next pps (synchronously)
http://files.ettus.com/uhd_docs/manual/html/usrp2.html#ref-clock-10mhz
The N2XX notes contained there should apply to the B100 as well.
-- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org
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