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

[Erik Skovgaard]

Hi Doug,

It works great here, thanks!

73 de ve7mdl,                       ....Erik.

------ Original Message ------
From: "Doug W5WC" <w5wc at windstream.net>
To: apache-labs at yahoogroups.com; hpsdr at openhpsdr.org
Sent: 25/04/2015 11:17:30
Subject: [hpsdr] PowerSDR/OpenHPSDR mRX PS v3.2.25 released

>***** 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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