[hpsdr] HAM RADIO Friedrichshafen 2016

[Helmut]

All,

The appearance of openHPSDR at the HAM RADIO Friedrichshafen 2016 will be
split in two sessions.

At 11.55 to 13:45 CEST on Saturday, 26thof June, as part of HPSDR block of
the SDR Academy (
http://www.darc.de/home/details/article/sdra-programm-2016-ist-fertig/ )our
top developers will report about new and sophisticated projects:

 

.         John Melton, G0ORX/N6LYT: 'Stand-alone HPSDR Transceiver using
low-cost processors'. Software, specifically written to run on low-cost ARM
processors such as the Raspberry Pi 2, Odroid C1+ and Pine 64, supports all
HPSDR/Apache Labs radios using both the original Ethernet protocol and the
new protocol. The software uses a version of WDSP that has been ported to
Linux and has been written in C, using GTK+ for the GUI toolkit, to work
with a small touch screen display (typically 800x480) and supports rotary
encoders and push buttons along with the touch screen for a "Knobs and
Buttons" user interface. John will present a powerful direct-sampling SDR
solution for QRP and portable operation.

 

.         Phil Harman, VK6PH:  'Direct Fourier Conversion (DFC) - An
alternative architecture for Software Defined Radios'.  Most of the latest
SDRs use an Analogue to Digital Converter (ADC) close to the antenna
followed by Digital Down Conversion (DDC).  DDC is usually performed in an
FPGA or ASIC and is used to reduce the bandwidth and data rate of the
samples that are subsequently processed by a microprocessor, PC or single
board computer. However, with the availability of low cost and high
performance Graphics Processing Units (GPUs) an alternative architecture can
be used that has a number of advantages over the current DDC approach.  Phil
will present the theory and some practical examples of this alternative
architecture. 

.         Dr. Warren C. Pratt, NR0V:  'Advanced Algorithms for Noise
Blanking and Noise Reduction'.  Wideband noise-blankers and LMS
noise-reduction algorithms are commonplace in modern SDRs.  With today's CPU
power, more advanced algorithms offering superior performance are also
available. Warren focuses on two such algorithms implemented in 2015 in the
WDSP library used for the openHPSDR program: 1. The Spectral Noise Blanker
uses linear predictive coding and often removes impulse noise under
conditions where wideband blankers are ineffective.  Impulses are detected
by comparing the observed waveform with a predicted waveform.  Impulses are
corrected by recreating an estimate of corrupt portions of the original
waveform using spectral information. 2. The Spectral Noise Reduction
algorithm operates in the frequency domain and, based upon statistical
models of speech and noise, reduces random noise much more effectively than
LMS algorithms.  The seminal work for this approach was published by Yariv
Ephraim and David Malah in 1984.  However, the state of the art has advanced
substantially over the past thirty years.

 

.         Adam Farson, VA7OJ/AB4OJ:'Evaluating Digital Receivers' The second
and third-order intercept points (IP2 and IP3) are figures of merit for TRX
specifications and allow distortion products to be computed for various
signal amplitudes.  Advanced SDR designs employing the ADC close to the
antenna, require modified test methods to characterize strong signal
performance. Terms like IP3 or intermodulation-free dynamic range fail and
also terms like dither or random noise get meaning. Noise Power Ratio (NPR)
an old test procedure can be very useful to benchmark SDRs and legacy
analogue concepts as well. Adam will explain some fundamentals and test
results.

 

At 14.00 CEST - after a short break - we will continue until 16.00 with the
HPSDR forum to dive a bit deeper into a/m themes and to answer specific
questions of HPSDR/ANAN users. Adam, John, Phil, Warren and others will be
happy to inform SDR prospects about the advanced HPSDR technology.

 

See you in Friedrichshafen!

 

73, Helmut, DC6NY 

 

 

 

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