Hi,
I think I did not provide enough details.
I am using basic TX and basic RX. My idea was to measure delay between
the
tx pulse and the rx pulse but I cannot because the rx signal is not
stable
in the oscilloscope. The delay between the signals is random. It can be
0.075 ms, 0.30 ms (see images) sometimes the pulse is even
negative!..it
doesn’t make sense to me.
My GRC file is:
<?xml version='1.0' encoding='ASCII'?><flow_graph>
Wed Oct 13 10:03:03 2010
options
id
top_block
_enabled
True
title
author
description
window_size
1280, 1024
generate_options
wx_gui
category
Custom
run
True
realtime_scheduling
_coordinate
(10, 10)
_rotation
0
usrp2_sink_xxxx
id
usrp2_sink_xxxx_0
_enabled
True
type
complex
interface
mac_addr
interpolation
500
frequency
90000000
lo_offset
float(‘inf’)
gain
0
_coordinate
(1034, 26)
_rotation
0
usrp2_source_xxxx
id
USRP2_source
_enabled
True
type
complex
interface
mac_addr
decimation
500
frequency
90000000
lo_offset
float(‘inf’)
gain
0
_coordinate
(209, 208)
_rotation
0
gr_null_sink
id
gr_null_sink_0
_enabled
True
type
float
vlen
1
_coordinate
(957, 308)
_rotation
0
gr_float_to_complex
id
gr_float_to_complex_0
_enabled
True
vlen
1
_coordinate
(669, 59)
_rotation
0
gr_complex_to_float
id
gr_complex_to_float_0
_enabled
True
vlen
1
_coordinate
(636, 272)
_rotation
0
wxgui_scopesink2
id
wxgui_scopesink2_0_0_0_0
_enabled
True
type
float
title
Scope Plot
samp_rate
200000
v_scale
0
t_scale
0
ac_couple
False
xy_mode
False
num_inputs
2
grid_pos
1,1,1,1
notebook
_coordinate
(863, 151)
_rotation
0
gr_vector_source_x
id
gr_vector_source_x_0
_enabled
True
type
float
vector
1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0,
0, 0, 0
repeat
True
vlen
1
_coordinate
(205, 124)
_rotation
0
gr_throttle
id
gr_throttle_0
_enabled
True
type
float
samples_per_second
200000
vlen
1
_coordinate
(428, 165)
_rotation
0
<source_block_id>USRP2_source</source_block_id>
<sink_block_id>gr_complex_to_float_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
<source_block_id>gr_float_to_complex_0</source_block_id>
<sink_block_id>usrp2_sink_xxxx_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
<source_block_id>gr_complex_to_float_0</source_block_id>
<sink_block_id>gr_null_sink_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
<source_block_id>gr_throttle_0</source_block_id>
<sink_block_id>gr_float_to_complex_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
<source_block_id>gr_throttle_0</source_block_id>
<sink_block_id>wxgui_scopesink2_0_0_0_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
<source_block_id>gr_complex_to_float_0</source_block_id>
<sink_block_id>wxgui_scopesink2_0_0_0_0</sink_block_id>
<source_key>1</source_key>
<sink_key>1</sink_key>
<source_block_id>gr_vector_source_x_0</source_block_id>
<sink_block_id>gr_throttle_0</sink_block_id>
<source_key>0</source_key>
<sink_key>0</sink_key>
</flow_graph>
If it is important, I get a lot of messages like:
usrp2::tx_raw: FIXME: short packet: 7 items (56 bytes)
usrp2::tx_raw: FIXME: short packet: 7 items (56 bytes)
usrp2::tx_raw: FIXME: short packet: 7 items (56 bytes)
Many thanks,
Jorge
Hello all,
I did some test when transmitting and receiving a pulse. After seeing the
transmitted and received signal on a single oscilloscope (in GRC).Flowgraph:
Vector source - Oscilloscope A - Rational resampler - USRP2 sink (500
interpolation)
USRP2 source (500 decimation) - Rational resampler - Oscilloscope A - Nule
sinkThe received pulse signal is not stable (oscilloscope triggered with tx
signal). It is like random phase so that I can not measure the delay
between
transmitted and received pulse.
I expected to have two fix pulsed signals in the oscilloscope at a fixed
delay.How can I do it?