[linux-dvb] A/V sync issues with DVB-S

Simon Kenyon simon at koala.ie
Thu Aug 21 11:59:55 CEST 2008


Steven Toth wrote:
> Antti Palosaari wrote:
>   
>> Thomas Börkel wrote:
>>     
>>> hermann pitton wrote:
>>> Measuring the strength and SNR is not so easy now. My SAT receiver
>>> always says strength 70% and SNR 80%. My new Nova S Plus cards always
>>> report strength 97% and SNR 99%. Only my TT 1500s reported reasonable
>>> numbers like strength 63-80% and SNR 75-90%.
>>>       
>> What is the recommended way to report signal strength or SNR by the 
>> driver? Both of those are 16bit unsigned value. Is it better to scale 
>> 0-0xffff or return as decibels? If SNR is reported as decibels it will 
>> look like very small value...
>>
>> Antti
>>     
>
> May of the drivers I've added recently report their values in db, but I 
> typically also have one precision point. So I report 20.4 as 204 decimal.
>
> - Steve
>
>
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would it be possible to define a standard and then normalise the results 
to that range.
i realise that it might take a year or more before all drivers adopted 
this "standard".
but it would be worth it to at least declare one.

i see this sort of discussion on this list at least once a fortnight.
i also want to build a signal strength meter for a dish installation 
tool i'm trying to write
--
simon



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