I have two USRP B100 and I am
trying to sync them
for that I have connected them both
to reference and 1pps from the same
source
the source is a rubidium standard
source reference
it has a 10MHZ 1Vrms 50 ohm sine and
1pps outputs. I have tested it with a
scope to see if its stable.
for my test I transmit from one USRP B100,
and receive from the other USRP.
I configured both devices for:
clock source: external
time source: external
sync: unknown 1pps
tested the output with WX GUI FFT Sink on the Rx
side
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.
whenever 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)
I am using the latest version of GNU Radio
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 files
here 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)