<s>
GNU	B-Application
Radio	I-Application
is	O
a	O
free	B-Application
software	I-Application
development	I-Application
toolkit	O
that	O
provides	O
signal	O
processing	O
blocks	O
to	O
implement	O
software-defined	B-Architecture
radios	I-Architecture
and	O
signal-processing	O
systems	O
.	O
</s>
<s>
It	O
can	O
be	O
used	O
with	O
external	O
RF	O
hardware	O
to	O
create	O
software-defined	B-Architecture
radios	I-Architecture
,	O
or	O
without	O
hardware	O
in	O
a	O
simulation-like	O
environment	O
.	O
</s>
<s>
The	O
GNU	B-Application
Radio	I-Application
software	O
provides	O
the	O
framework	O
and	O
tools	O
to	O
build	O
and	O
run	O
software	B-Architecture
radio	I-Architecture
or	O
just	O
general	O
signal-processing	O
applications	O
.	O
</s>
<s>
The	O
GNU	B-Application
Radio	I-Application
applications	O
themselves	O
are	O
generally	O
known	O
as	O
"	O
flowgraphs	O
"	O
,	O
which	O
are	O
a	O
series	O
of	O
signal	O
processing	O
blocks	O
connected	O
together	O
,	O
thus	O
describing	O
a	O
data	O
flow	O
.	O
</s>
<s>
As	O
with	O
all	O
software-defined	B-Architecture
radio	I-Architecture
systems	O
,	O
reconfigurability	O
is	O
a	O
key	O
feature	O
.	O
</s>
<s>
Instead	O
of	O
using	O
different	O
radios	O
designed	O
for	O
specific	O
but	O
disparate	O
purposes	O
,	O
a	O
single	O
,	O
general-purpose	O
,	O
radio	O
can	O
be	O
used	O
as	O
the	O
radio	O
front-end	O
,	O
and	O
the	O
signal-processing	O
software	O
(	O
here	O
,	O
GNU	B-Application
Radio	I-Application
)	O
,	O
handles	O
the	O
processing	O
specific	O
to	O
the	O
radio	O
application	O
.	O
</s>
<s>
These	O
flowgraphs	O
can	O
be	O
written	O
in	O
either	O
C++	B-Language
or	O
Python	B-Language
.	O
</s>
<s>
The	O
GNU	B-Application
Radio	I-Application
infrastructure	O
is	O
written	O
entirely	O
in	O
C++	B-Language
,	O
and	O
many	O
of	O
the	O
user	O
tools	O
(	O
such	O
as	O
GNU	B-Application
Radio	I-Application
Companion	O
)	O
are	O
written	O
in	O
Python	B-Language
.	O
</s>
<s>
GNU	B-Application
Radio	I-Application
is	O
a	O
signal-processing	O
package	O
and	O
part	O
of	O
the	B-Application
GNU	I-Application
Project	I-Application
.	O
</s>
<s>
It	O
is	O
distributed	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
,	O
and	O
most	O
of	O
the	O
project	O
code	O
is	O
copyrighted	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
.	O
</s>
<s>
First	O
published	O
in	O
2001	O
,	O
GNU	B-Application
Radio	I-Application
is	O
an	O
official	O
GNU	B-Application
package	I-Application
.	O
</s>
<s>
Philanthropist	O
John	O
Gilmore	O
initiated	O
GNU	B-Application
Radio	I-Application
with	O
the	O
funding	O
of	O
$	O
320,000	O
(	O
US	O
)	O
to	O
Eric	O
Blossom	O
for	O
code	O
creation	O
and	O
project-management	O
duties	O
.	O
</s>
<s>
GNU	B-Application
Radio	I-Application
began	O
as	O
a	O
fork	B-Application
of	O
the	O
Pspectra	O
code	O
that	O
was	O
developed	O
by	O
the	O
SpectrumWare	O
project	O
at	O
the	O
Massachusetts	O
Institute	O
of	O
Technology	O
(	O
MIT	O
)	O
.	O
</s>
<s>
In	O
2004	O
,	O
a	O
complete	O
rewrite	O
of	O
GNU	B-Application
Radio	I-Application
was	O
completed	O
,	O
so	O
today	O
GNU	B-Application
Radio	I-Application
no	O
longer	O
has	O
any	O
original	O
Pspectra	O
code	O
.	O
</s>
<s>
Matt	O
Ettus	O
joined	O
the	O
project	O
as	O
one	O
of	O
the	O
first	O
developers	O
,	O
and	O
created	O
the	O
Universal	O
Software	B-Architecture
Radio	I-Architecture
Peripheral	O
(	O
USRP	O
)	O
to	O
provide	O
a	O
hardware	O
platform	O
for	O
use	O
with	O
the	O
GNU	B-Application
Radio	I-Application
software	O
.	O
</s>
<s>
In	O
2004	O
,	O
Matt	O
founded	O
Ettus	O
Research	O
LLC	O
and	O
began	O
selling	O
USRPs	O
that	O
worked	O
with	O
GNU	B-Application
Radio	I-Application
.	O
</s>
<s>
In	O
2011	O
,	O
the	O
GNU	B-Application
Radio	I-Application
project	O
began	O
holding	O
a	O
yearly	O
conference	O
,	O
called	O
"	O
GRCon	O
"	O
,	O
which	O
generally	O
has	O
a	O
Hackfest	O
on	O
the	O
last	O
day	O
of	O
the	O
conference	O
.	O
</s>
<s>
In	O
September	O
2020	O
,	O
GNU	B-Application
Radio	I-Application
became	O
part	O
of	O
the	O
SETI	O
Institute	O
(	O
a	O
non-profit	O
,	O
multi-disciplinary	O
research	O
and	O
education	O
organization	O
)	O
for	O
all	O
financial	O
and	O
contractual	O
purposes	O
.	O
</s>
<s>
In	O
October	O
2020	O
,	O
Ben	O
Hilburn	O
and	O
the	O
project	O
officers	O
at	O
the	O
time	O
voted	O
to	O
reorganize	O
the	O
GNU	B-Application
Radio	I-Application
Project	O
's	O
leadership	O
,	O
forming	O
a	O
General	O
Assembly	O
with	O
a	O
set	O
of	O
by-laws	O
that	O
regulate	O
details	O
of	O
how	O
the	O
organization	O
operates	O
.	O
</s>
<s>
The	O
GNU	B-Application
Radio	I-Application
Companion	O
is	O
a	O
graphical	B-Application
UI	I-Application
used	O
to	O
develop	O
GNU	B-Application
Radio	I-Application
applications	O
.	O
</s>
<s>
This	O
is	O
the	O
front-end	O
to	O
the	O
GNU	B-Application
Radio	I-Application
libraries	O
for	O
signal	O
processing	O
.	O
</s>
<s>
GRC	O
was	O
developed	O
by	O
Josh	O
Blum	O
during	O
his	O
studies	O
at	O
Johns	O
Hopkins	O
University	O
(	O
2006-2007	O
)	O
,	O
then	O
distributed	O
as	O
free	B-Application
software	I-Application
for	O
the	O
October	O
2009	O
Hackfest	O
.	O
</s>
<s>
Starting	O
with	O
the	O
3.2.0	O
release	O
,	O
GRC	O
was	O
officially	O
bundled	O
with	O
the	O
GNU	B-Application
Radio	I-Application
software	O
distribution	O
.	O
</s>
<s>
When	O
a	O
flowgraph	O
is	O
"	O
compiled	O
"	O
in	O
GRC	O
,	O
it	O
generates	O
Python	B-Language
code	I-Language
that	O
creates	O
the	O
desired	O
GUI	B-Application
windows	O
and	O
widgets	O
,	O
and	O
creates	O
and	O
connects	O
the	O
blocks	O
in	O
the	O
flowgraph	O
.	O
</s>
<s>
GRC	O
currently	O
supports	O
GUI	B-Application
creation	O
using	O
the	O
Qt	B-Language
toolkit	I-Language
.	O
</s>
<s>
GNU	B-Application
Radio	I-Application
provides	O
many	O
common	O
plotting	O
and	O
data	O
visualization	O
data	O
sinks	O
,	O
including	O
FFT	O
displays	O
,	O
symbol	O
constellation	O
diagrams	O
,	O
and	O
scope	O
displays	O
.	O
</s>
<s>
Many	O
users	O
create	O
"	O
out-of-tree	O
modules	O
"	O
for	O
use	O
with	O
GNU	B-Application
Radio	I-Application
.	O
</s>
<s>
To	O
manage	O
these	O
,	O
and	O
the	O
dependencies	O
required	O
to	O
run	O
GNU	B-Application
Radio	I-Application
,	O
the	O
organization	O
created	O
the	O
PyBOMBS	O
(	O
Python	B-Language
Build	O
Overlay	O
Managed	O
Bundle	O
System	O
)	O
project	O
.	O
</s>
