Re: [linrad] Linrad-02.35

["John Harrison, NI1B" <nei.mv.com; jmh6@xxxxxxxxxxxxxxxx>]

Hi Leif,

  Regards old computers. I'll see if I can get myself organized enough to
be helpful.... I DO have quite a pile....

  Maybe if you make me a 'to do' list, I'll try it that way.

  And on the amusement side. As far as I can determine I am the only
person in the world still using an original IBM PC for real work (4.77 mhz
dual 5 1/4 inch drives. It's used in a production tester. Still works
great.

  warm regards,
  john


On Thu, 12 Jul 2007, Leif Asbrink wrote:

> Hi All,
> 
> This new version is only available at the bottom of
> the development page:
> http://www.sm5bsz.com/linuxdsp/linroot.htm
> and its mirrors. At "Linrad home page" the version
> is still 02-34.
> 
> Linrad now has a speech processor, the first step
> towards a transmit chain. The dsp side of it seems
> to work fine, but the hardware (=Delta44) does 
> not quite work as expected. Data sheets typically say 
> that the D/A is better than the A/D, but in real
> life it seems to be the other way around. So far I
> have only tested un-modified soundcards and the next step
> will be to see if there are any mods that might help.
> Another possible improvement could be to use all four
> D/A channels and send both I and Q in two opposite
> phases so a differential amplifier could be used.
> Interferences might be in the same phase and cancel out...
> 
> Other changes:
> 
> A wheel mouse can now be used to tune the Linrad frequency
> in steps of the bin size in the main waterfall. By turning
> the depressed wheel one can make the step size multiples
> of the bin size.
> 
> The network now sends the time when a recording was made,
> so now MAP65 should get the correct time stamps to decode 
> automatically on "S-files"
> 
> Feedback wanted:
> 
> 1) Is there anyone interested in using Linrad on old computers?
> Things older than Pentium III. Linrad works OK on as old 
> machines as Pentium 66 MHz for low bandwidths, but I have
> a problem with too many computers around to be able to start
> looking into tx hardware. I contemplate to get rid of Pentium I
> and Pentium MMX but if several people have an interest I will
> move them elsewhere to keep the possibillity to occasionally verify
> that those old computers still are OK with Linrad.
> 
> 2) There is a part in Linrad "voicelab" by which one can study
> speech processors. I wrote it in a hope it would be possible
> to find ways to improve differently for different voices.
> As it turned out, the conclusion was that the only important
> aspect when it comes to copyability under marginal conditions 
> is the average to peak power. The new speech processor is designed
> for that and Linrad will not use any part of voicelab any more. 
> Is there any interest in voicelab? If not I will remove it.
> 
> 
> 
> I will be away for about a week, probably without E-mail,
> leaving tomorrow (Friday) late evening. I look forward to
> bug reports on return home :-)
> 
> 73  
> 
> Leif / SM5BSZ
> 
> 
>  
> 
> 
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