Contributors this release:

Alick Zhao <>
Alexandru Csete <>
Ben Hilburn <>
Ben Reynwar <>
Brett L. Trotter <>
Johnathan Corgan <>
Josh Blum <>
Julien Olivain <>
Martin Braun <>
Michael Dickens <>
Nicholas Corgan <>
Tim O'Shea <>
Tim Newman <>
Tom Rondeau <>

Addition/upgrade of message passing infrastructure (Tim O'Shea, Tom
Rondeau, Johnathan Corgan, Josh Blum)

This introduces the ability to add and connect formally defined
asychronous message ports to signal processing blocks and
hierarchical blocks. These message ports can be connected to pass
asynchronous data in the form of PMTs (polymorphic types) among
blocks in a flowgraph. It is also possible to implement pure
message passing blocks that have no requirement for streaming
ports or work functions.

We've also introduced the concept of PDUs (Protocol Data Units) as
a convention for passing data+metadata using the new messaging
ports. A PDU is a PMT pair that combines a PMT dictionary of
metadata keys/values along with a PMT blob to hold a vector of
data in memory.

A few new general purpose blocks supporting these capabilties are
in gnuradio-core:

gr_message_debug
gr_message_strobe
gr_tagged_stream_to_pdu
gr_pdu_to_tagged_stream

Two new blocks for interfacing with networking stacks using the
new PDU semantics:

gr_socket_pdu
gr_tuntap_pdu

This new message passing capability and PDU convention is aimed at
providing the infrastructure to better support software radio
implementations using packet-oriented semantics, such as MAC-layer
processing.

Addition of new Python-based signal processing blocks (Josh Blum)

This feature, originally introduced by Josh Blum as part of
GrExtras, allows implementing signal processing blocks directly in
Python, and has now become a standard feature of GNU Radio.

Addition of gr-analog top-level component (Tom Rondeau)

This implements the current gnuradio-core signal processing blocks
used for analog signal processing into their own top-level
component, gr-analog, and uses the new 3.7 API organization. The
original blocks in gnuradio-core will be removed on the 3.7 branch
prior to 3.7 release.

Addition of gr-blocks top-level component (Johnathan Corgan)

This implements a large portion of the gnuradio-core non-signal
processing blocks in the 3.7 API form. The original blocks in
gnuradio-core will be removed on the 3.7 branch prior to 3.7
release.

Metadata file source and sink blocks (Tom Rondeau)

Two new blocks implement enhanced file source and sink blocks that
incorporate metadata passed using the stream tags feature in GNU
Radio. It is now possible to store things like frequency and
sample rate into capture files, or whatever key/value pairs you
tag onto data streams inside a flowgraph.

http://www.trondeau.com/home/2012/12/15/metadata-file-format.html

GNU Radio buffer latency control (Tim O'Shea, Tom Rondeau)

For finer-grained control over latency inside a GNU Radio
flowgraph, it is now possible to adjust, on a per-block basis, the
maximum noutput_items that will be used to call a block work
function. In addition, it is possible to set the maximum size an
output buffer can grow to before a work function is called.

New GNU Radio Companion (GRC) capabilities

Added optional flag to pad source and sink (Josh Blum)
Added wildcard type to pad source and sink (Josh Blum)
Added ability to reload XML for block (Tim O'Shea)
Added ability to automatically create hier_blocks from a flowgraph (Tim Newman)
Added ability to open custom GRC hier block definitions (Tim O'Shea)
Added new grcc command line GRC-to-Python utility (Tom Rondeau)

New Documentation Updates (Tom Rondeau)

We are introducing documentation into the Doxygen manual
describing features and capabilities of GNU Radio, above and
beyond just documenting the API functions. Tom Rondeau has
written about this here:

http://www.trondeau.com/home/2012/12/18/new-documentation-for-new-features.html

Some examples of commits where this has been done:

http://gnuradio.org/cgit/gnuradio.git/commit/?id=77ea309 (PMT type usage)
http://gnuradio.org/cgit/gnuradio.git/commit/?id=a21c5f7 (Message passing interface)
http://gnuradio.org/cgit/gnuradio.git/commit/?id=996e599 (Metatdata format)
http://gnuradio.org/cgit/gnuradio.git/commit/?id=5fcb7eb (Max output buffer control)

Other new features:

Allow file source to open new files while running (Brett L. Trotter)
Allow source blocks to return none/yield (Josh Blum)
Improved capabilities of uhd_fft.grc example in gr-uhd (Ben Hilburn)
Added parameter in qtgui sink's GRC block to set the update rate (Julien Olivain)
Added source block hook in gr-uhd for issue stream cmd (Josh Blum)
Added cmake package support for Ubuntu 12.10 (Nicholas Corgan)
Added gr::blocks::patterned_interleaver (Tim O'Shea)
Allow user to set Python path during cmake configuration (Tom Rondeau)
Enabled serialize/deserialize for PMT vectors (Tom Rondeau)
Added unsigned long long int support to the PMT sugar functions (Tom Rondeau)
Allow using pmt_init_Xvector methods in python (Tom Rondeau)

Bug fixes:

Numerous cmake related bug-fixes (Josh Blum, Johnathan Corgan, Tom Rondeau)
Overhaul of cmake include directory ordering (Michael Dickens)
Fixed parallel build failures in cmake (Tom Rondeau)
Fixed segfaults due to old, no longer nedded SWIG workaround (Tom Rondeau)
Fixed memory leak issue in arbitrary resampler blocks (Tom ROndeau)
Fixed use of default noise seed in channel model (Alick Zhao)
Fixed scaling bug in QAM constellations (Ben Reynwar)
Fixed installation of grc examples (Johnathan Corgan)
Fixed finding Qwt6 installed on OSX using MacPorts (Ben Reynwar)
Fixed implicit assumption in skiphead (Josh Blum)
Fixed include tag include usage throughout core (Josh Blum)
Fixed incorrect private usage in gr_endian_swap (Josh Blum)
Fixed segfault in gr-filter due to memory free bug (Josh Blum)
Fixed UHD pmt tuple ref namespace issue (Josh Blum)
Fixed gr_tag_debug to handle lacking srcid (Martin Braun)
Fixed gr-analog for 'sincos(f)' on MacOSX (Michael Dickens)
Fixed gr-analog build issues on Windows (Nicholas Corgan)
Fixed qtgui time sink to take the bandwidth parameter to set x-axis correctly (Tom Rondeau)
Fixed float-in, complex-out fft block to use the right io sig (Tom Rondeau)
Fixed Clang imcompatibility by removing '.version' lines in ASM code in core (Tom Rondeau)
Fixed file_meta_source/sink incompatibilities with MSVC (Nicholas Corgan)
Fixed some unused parameter warnings (Alexandru Csete)