[hpsdr] PowerSDR/OpenHPSDR mRX PS v3.2.25 released

Wed Apr 29 03:08:10 PDT 2015

***************************
Working beautifully here on my Atlas based system.
NR2 is impressive!
Thanks and 73,
Hans VK5YX
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On 26/04/15 03:47, Doug W5WC wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> All,
>
> PowerSDR/OpenHPSDR mRX PS v3.2.25 has been released.
>
> This release can be downloaded from the openhpsdr.org website.
> http://openhpsdr.org/download.php
>
> This release contains the following changes:
>
> * Further Advancement for NR2.  NR2 has been further enhanced with a new
> "Gamma" gain method.  While the change from the previous NR2 is small, this
> further advance has been demonstrated to slightly further reduce background
> noise and also to reduce certain audio artifacts of the noise reduction
> process.  After a database reset, this will become your default gain method
> --- so no need to worry about selecting it.
>
> * PureSignal Auto-Attenuate.  One of the more difficult parts of PureSignal
> setup has been adjusting the attenuator during TX to optimize performance.
> There is now an option (selected by default, on the Linearity window) to set
> the attenuator automatically for you.  When PureSignal begins a calibration,
> if the attenuator is not set correctly, it will calculate a new value, turn
> itself OFF, apply the new value, and turn itself back ON.  In the event that
> the initial condition is one of too much attenuation, the new value should
> be correctly calculated and applied in a single step.  In the event there is
> not enough attenuation and the ADC is in overload, multiple steps may be
> required.
>
> * Protection for External Linear Amplifiers.  Some external amplifier
> manufacturers caution users that they must connect "ALC" from the amplifier
> to the exciter so that the exciter will reduce drive to protect the
> amplifier in the event of certain types of faults, e.g., over-current, arc,
> high-SWR, etc.  This has not previously been an option with openHPSDR
> exciters since no connection has been provided on these exciters.  Clyde,
> K2UE, has led a project to develop an appropriate hardware interface for
> this.  Software support has been added to enable the use of this interface.
> Documentation will soon be posted and the location announced.  While you can
> certainly build your own hardware interface from this documentation, also
> stay-tuned for a possible future announcement on availability of hardware.
>
> * Workaround for using the Ext1/2/XVTR ports on the rev24 PA board with
> receive only antennas. To use a receive only antenna with the 100W ANAN
> radios shipped since Feb 2015 you will need to check the "Disable BYPASS"
> box located near the bottom of the Setup=>General=>Ant/Filters=>Antenna
> page. Please do not use this with previous versions of the PA boards.
>
> * As usual, several bug-fixes and clean-up items.
>
> NR2 - MORE INFORMATION
>
> NR2 has received particularly positive feedback since its introduction a few
> weeks ago.  While all noise reduction algorithms tend to have some audio
> artifacts, the NR2 algorithm has been reported to be quite effective in
> reducing background noise without the tiring sound of typical LMS
> algorithms.  Several people have reported that they leave it enabled all the
> time.  There have also been a few questions on usage; so, we'll provide some
> clarification here.
>
> Activation:  NR2 is selected using the same button as NR.  From the OFF
> state, click once to get NR (the normal SDR LMS type algorithm) and click
> again to get NR2 (a very different type of algorithm). Clicking a third time
> will get you back to the OFF state.
>
> Noise Reduction and AGC:  AGC, if not properly adjusted, is the enemy of
> noise reduction algorithms!  The reason is simple - AGC's job is to adjust
> gain to bring things to the same level, whether those things are two
> different signals or a signal and the noise during the speech pauses.  So,
> when NR/NR2 is trying to reduce noise, if AGC is trying to restore it, they
> are in conflict.  For proper operation, there are two things to observe:
> (1) Set your AGC gain properly, and (2) if you experience AGC-pumping of the
> noise level when using NR/NR2, try selecting the "Pre-AGC" use of NR/NR2
> rather than having it "Post-AGC".
> - AGC gain can most easily be correctly adjusted by displaying the green "G"
> line on the panadapter and pulling it up to be a few dB above the noise
> floor - experiment and you'll see how it works.  To display the line, see
> Setup/DSP/AGC-ALC.  To move it, "grab" the green square at the left side
> using your left mouse button.
> - To select Pre-AGC, see Setup/DSP/NR-ANF.
>
> Other Settings:  You will note that there are other settings for NR2
> available on the Setup/DSP/NR-ANF tab.  I recommend you select "Gamma"
> as the gain-method, either "OSMS" or "MMSE" as the NPE-method, and leave
> AE-Filter checked.  These settings match the default settings.  In other
> words, there's nothing you need to do here.  On the other hand, if you wish
> to experiment, and if you find some different combination that works better
> in some special situation, please let us know!  That will be helpful for
> future developments.
>
>
> You WILL need to reset your database for this release.
>
> Thanks & 73,
>
> Doug, W5WC
> Warren, NR0V
>
>
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