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RE: [linrad] SSB Parameters

Hi all,


I am leaving home for a week now so I will not respond to
any comment now. Maybe not after I get home either because
my mailbox may become flooded with junk.

I have added suggested changes to the parameters Roger sent.

> First FFT bandwidth (Hz) [83]
> First FFT window (power of sin) [2]
> First forward FFT version [0]      //change to 5  (much faster)
> First FFT storage time (s) [1]     //change to 10 (unless you have small 
                                memory. Allows longer averaging times)   
> First FFT amplitude [1000]
> Enable second FFT [1]
> First backward FFT version [0]     // 1 is much faster, but with Linrad-01.26
                                there will be advantages of using floating point
                                Linrad-01.25 and earlier best use 1 here.   
> Sellim maxlevel [6000]
> First backward FFT att. N [6]
> Second FFT bandwidth factor in powers of 2 [2]  //change to 0 or 1. Typicaly no
                                     need for narrow filtering in waterfalls for SSB
> Second FFT window (power of sin) [0]   //change to 2. Gives better filters.
> Second forward FFT version [0]  // 2 is much faster, but with Linrad-01.26
                                there will be advantages of using floating point
                                Linrad-01.25 and earlier best use 2 here.   
> Second forward FFT att. N [7]
> Second FFT storage time (s) [5]
> Enable AFC/SPUR/DECODE [1]      // Use 1 here only if you actually want to use
                                 spur removal. AFC should not be used for SSB so
                                 make the window small and make it inactive on screen.
> AFC lock range Hz [150]
> AFC max drift Hz/minute [100]
> Enable Morse decoding [0]
> Max no of spurs to cancel [100]
> Spur timeconstant (0.1sek) [5]
> First mixer bandwidth reduction in powers of 2 [4] 
> First mixer no of channels [1]
> Baseband storage time (s) [200]  //!!! Use much smaller time here. At high bandwidth
                                 this would require very much memory. Many arrays are allocated
                                in the baseband for CW decoding. They are useless in ssb mode 
                                 but I have not removed memory allocation in ssb mode yet.
                               In cw with a bandwidth of 50Hz or less, the sampling speed is very
                               low and this is no problem.
> Output delay margin (0.1sek) [5]    //maybe you can make this smaller. Check the margin with 'T'
> Output sampling speed (Hz) [10000]  
> Default output mode [1]
> Audio expander exponent [3]
> A/D speed [96000]
> Check [1110107]
> 
> Change only between brackets.
> If file has errors, Linrad will ignore file and prompt
> for a complete set of new parameters
> 
> linrad-01.21
> 
> -----end of SSB parameters
> 
> 
> Here are my wcw parameters:
> 
> First FFT bandwidth (Hz) [100]
> First FFT window (power of sin) [3]
> First forward FFT version [2]            //as above
> First FFT storage time (s) [20]
> First FFT amplitude [1000]
> Enable second FFT [1]
> First backward FFT version [1]
> Sellim maxlevel [6000]
> First backward FFT att. N [6]
> Second FFT bandwidth factor in powers of 2 [4]
> Second FFT window (power of sin) [4]     //this is overkill on a big transform. Use 2
> Second forward FFT version [2]
> Second forward FFT att. N [10]
> Second FFT storage time (s) [15]         //It could be good to use 30 here if you want
                                   AFC to follow a really weak signal with a large delay
> Enable AFC/SPUR/DECODE [1]
> AFC lock range Hz [150]
> AFC max drift Hz/minute [100]
> Enable Morse decoding [0]
> Max no of spurs to cancel [100]
> Spur timeconstant (0.1sek) [5]
> First mixer bandwidth reduction in powers of 2 [4]
> First mixer no of channels [1]
> Baseband storage time (s) [150]         // Use smaller here unless you want long time
                                       average spectra from the baseband.
> Output delay margin (0.1sek) [5]
> Output sampling speed (Hz) [6000]
> Default output mode [1]
> Audio expander exponent [3]
> A/D speed [96000]
> Check [1110107]
> 
> Change only between brackets.
> If file has errors, Linrad will ignore file and prompt
> for a complete set of new parameters
> 
> linrad-01.25
> 
> With the SSB parameters I get a delay on the order of 0.5-0.7 seconds or  
> less.  I am not sure of the delay with the CW parameters listed 
> above, as  
> I didn't check it today, but generally I have had delays of 2-5 seconds  
> [which are not a problem for my purposes].
> 
> I post them with no representation as to their optimization.  
> Rather, they  
> are being posted to provide an object for criticism, and to provide a  
> framework for the discussion of the tradeoffs and consequences of 
> specific  
> parameter choices.
> 
> These are running on this system:
> 
> CPU::  Pentium 3
> CPU Speed::  1 GHz
> RAM in MB::  770 MB
> SOUND CARD::  M-Audio Delta44
> SOUND DRIVER::  OSS/Linux OSS 3.99.1g
> ADDITIONAL CARD1::  SoundBlaster PCI
> VIDEO CARD::  ATI Radeon 7000
> VIDEO DRIVER::  Rage 128
> LINUX DISTRIBUTION::  Red Hat
> LINUX VERSION::  8.0
> KERNEL VERSION::  2.4.20-28.8
> GCC VERSION::  3.2 20020903
> SVGALIB VERSION::  1.9.19
> LINRAD VERSION::  01.25
> 
> Hope that is of some interest, and
> 
> 73
> 
> Roger Rehr
> W3SZ
> 
> 
> -- 
> Roger Rehr
> W3SZ
> http://www.qsl.net/w3sz
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