[pskmail] Re: Robust psk-modes on raspberry pi
- From: John Douyere <vk2eta@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Tue, 19 Nov 2013 11:10:28 +1100
Tarmo,
The following patch fixes the bug. It exists also in X86 architectures but
it resolves differently and works regardless!
In psk.cxx, in the subroutine rx_symbol(...), replace the line:
softbit = (unsigned char) ((softangle / (1 + softamp)) -
127);
by:
softbit = (unsigned char) ((softangle / (1 + softamp)) +
127);
It has worked for others.
Regards,
John
On Fri, Nov 8, 2013 at 8:35 AM, John Douyere <vk2eta@xxxxxxxxx> wrote:
> Hello Tarmo,
>
> I have rechecked on both 386 and Android platforms and the THOR modes are
> more CPU intensive than PSKR modes on both platforms.
>
> Do you get proper decode in PSKR modes?
>
> Can you check the CPU load and memory usage with a "top" command for
> example?
>
> 73, John
>
>
> On Thu, Nov 7, 2013 at 1:38 AM, Tarmo Huttunen <tarmopaha@xxxxxxxxx>wrote:
>
>> I had short time to play with raspi today. I compared captured rx/tx text
>> on logfile to text on fldigi GUI.
>>
>> When fldigi receive rsid for psk-r mode, (125, 250 or 500) it stops
>> writing to logfile. Also received pskr-rsid will not be written to logfile,
>> even it will show up normally on GUI received text window.
>>
>> In thor 22, when rsid is received, notification will be written to
>> logfile.
>>
>> Raspi can send psk-r modes normally, it was only bad cable.
>>
>> I will be googling this subject later, to check if this problem have
>> appeared on other platforms.
>>
>> Tarmo
>> On Nov 5, 2013 11:27 AM, "Tarmo Huttunen" <tarmopaha@xxxxxxxxx> wrote:
>>
>>> John, you really now what you are talking about!
>>>
>>> Reason I started to think this is the fact that raspi indeed handels
>>> thor22 well, even with medium sink interpolator, but not psk-r modes at
>>> all. Or lets say I have never get it decoding psk-r, not even slower ones.
>>>
>>> You kind of confirmed my thoughts. I take this subject from back of my
>>> mind to my table, start to look it closer when I have time. After all I
>>> havent use raspi much after recent audio-related updates.
>>>
>>> Thanks, Tarmo
>>> On Nov 5, 2013 4:04 AM, "John Douyere" <vk2eta@xxxxxxxxx> wrote:
>>>
>>>> Hello Tarmo,
>>>>
>>>> If you have correct decoding with PSK modes but not PSKR modes then the
>>>> most likely reason is processing power.
>>>>
>>>> The processing load on the CPU is significantly higher due to the
>>>> double Viterbi decoder and interleavers used for the PSKR decode.
>>>>
>>>> I have seen that issue on the earlier Android devices when I developed
>>>> the andPskmail program.
>>>>
>>>> If you look at the rxpsk source code in the Android program (in Java)
>>>> you will see that I spend time to work around these limitations. One
>>>> solution I used quite effectively was to reduce the order of the filters to
>>>> free-up some resources.
>>>>
>>>> From memory I reduce the order from 64 to 32, which means a slight out
>>>> of band increase in interference but overall better than not having decode
>>>> at all.
>>>>
>>>> But if you say that TXing is also not decodable, then I suspect that
>>>> the CPU is simply not capable of processing that load.
>>>>
>>>> A good test would be to try the MFSK and THOR modes as well because the
>>>> MFSK modes are very resource effective and the THOR modes the most CPU
>>>> hungry.
>>>>
>>>> In my experience on the Android devices (from memory) here is the
>>>> approximate hierarchy of CPU load by mode:
>>>>
>>>> PSK31
>>>> ...
>>>> PSK500
>>>> MFSK16
>>>> ...
>>>> MFSK64
>>>> PSK63F
>>>> PSK125R
>>>> ...
>>>> PSK500R
>>>> THOR8
>>>> ...
>>>> THOR22
>>>>
>>>> So have a look if the top of the list works but not the bottom. That
>>>> should give you a good indication if the CPU is the issue or not.
>>>>
>>>> Also, have a look in Fldigi what interpolator you use. The linear one
>>>> is the most CPU efficient.
>>>>
>>>> I also assume you have already selected the "Slow CPU" option in Fldigi.
>>>>
>>>> 73, John
>>>>
>>>>
>>>>
>>>> On Tue, Nov 5, 2013 at 12:03 PM, Tarmo Huttunen <tarmopaha@xxxxxxxxx>wrote:
>>>>
>>>>> Hello...
>>>>>
>>>>> I have wondered this oddity with raspberry-fldigi-jpskmail for a while:
>>>>>
>>>>> Psk-r modes are not working. Sympton is, after psk-r id is received,
>>>>> raspberry does not decode anything. I mean, there will not come any
>>>>> characters on fldigi window. Is that "normal" sympton related to slow cpu?
>>>>>
>>>>> In normal pc-setups if psk-r decoding fails, there will come at least
>>>>> some nonsense text, am I right?
>>>>>
>>>>> I have started to wonder, if this psk-r problem is after all related
>>>>> to prosessing power at all? Could this have something to do with varicode
>>>>> used on psk-r modes? Missing symboltable or something similar?
>>>>>
>>>>> If I remember right, I also havent got pc to decode psk-r sent by
>>>>> raspberry. (This was not what I was testing, just something I happend to
>>>>> notice, and I am at work now, can not test again.)
>>>>>
>>>>> Do somebody have some advice for me, where should I look? Have
>>>>> somebody used robust psk-modes on some other low-resource machine?
>>>>>
>>>>> Thanks
>>>>> Tarmo, OH6ECF
>>>>>
>>>>
>>>>
>
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