[pskmail] Re: Robust psk-modes on raspberry pi

  • From: Franco Spinelli <frspin@xxxxxxxxx>
  • To: pskmail <pskmail@xxxxxxxxxxxxx>
  • Date: Wed, 20 Nov 2013 12:22:19 +0100

Thanks for the answer.

So delay is normal for PSKXXXR modes and signal bar slow dropoff is due to
a programming choice.

I will test Fldigi, patched as suggested, with Pskmail client and
PSK500R/PSK250R modes

Regards

Franco Spinelli
IW2DHW




2013/11/19 John Douyere <vk2eta@xxxxxxxxx>

> There are two factors here that makeup the delay in the display of
> characters.
>
> 1. The effect of the interleaver: as the encoded bits are spread over
> time, the decoder has to wait to see the end of the interleaver length to
> decide which bits to use.
>
> 2. The delay between the decoder thread processing and the display thread
> processing. If the cpu load increases, that delay increases.
>
> Now regarding the the slow dropoff of the signal bar. The mechanism to
> mark an end of signal is only used in psk modes as we had some false
> positives in pskr meaning that it would cut off in the middle of a
> transmission resulting in missing characters.
>
> Since pskr modes are almost always used in a modem situation I didn't
> bother looking for a replacement.
>
> Regards,
>
> John
>  On Nov 20, 2013 5:16 AM, "Franco Spinelli" <frspin@xxxxxxxxx> wrote:
>
>> Il 19/11/2013 15:25, John Douyere ha scritto:
>> > No apologies needed Franco, my post here was done after your email.
>> >
>> > I just didn't see it before I posted in the Fldigi list.
>> >
>> > I just mentioned it for consistency only.
>> >
>> > Thanks for your help in resolving that bug.
>> >
>>
>> I have applied you suggested patch to source code and now PSKXXXR modes
>> decode correctly.
>>
>> In all PSKXXXR modes and in PSK63F decoding there is a delay between
>> start of signal and start of characters in Rx panel.
>> After start of signal level indicator go high, stay high and after 1 or
>> 2 seconds text appear in RX panel. Last character decoded appear on RX
>> panel 1 or 2 seconds after the end of signal and, after then,
>> signal level slowly go down go reaches zero after 4 or 5 seconds
>>
>> This don't happen using PSK modes. Signal level go up and down during
>> reception and go down immediatly at the end of TX.
>>
>> No difference from your simple patch (change from -127 to +127), David
>> patch and your last patch as per your mail.
>>
>> This happen also on my Eeepc (Atom based). Is this correct?
>>
>> Regards
>>
>> Franco Spinelli
>>
>>
>>

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