[linux-dvb] [Proposal] Meaningful reporting of SNR

Manu Abraham abraham.manu at gmail.com
Wed Apr 12 18:32:46 CEST 2006


Rusty Scott wrote:
> On Wed, 2006-04-12 at 16:57 +0200, Robert Schlabbach wrote:
>   
>> From: "Rusty Scott" <rustys at ieee.org>
>>     
>>> 1)  That it be encouraged to report SNR in dB whenever possible.
>>>       
>> I'm afraid most hardware is incapable of producing such measurements.
>> Instead, I'd propose scaling all signal measurements to _percentages_.
>>     
> Currently done.  Causes confusion.  Percentage is meaningless.
>
> Why penalize the cards that are capable?  If SNR cannot be reported by a
> card then it shouldn't be throwing out a number that isn't
> representative of SNR.  If it is representative of SNR in some form, the
> manufacturers I've dealt with provide the formula to compute SNR in dB.
> SNR as a percentage is a useless number (Percentage of what? Largest
> possible value a card can produce?).  Given the number of questions
> concerning "What should I be seeing for SNR from XXX?" where the reply
> is it should be "big", there are a number of people looking for a
> meaningful, consistent, method to provide this information.  For ATSC
> and QAM there is an SNR point where errors begin to degrade the quality
> of what you see; the same applies to every transmission coding scheme.
>   

Yeah, i agree with you, we are working on it such that we can do some 
standardization. We are in fact working on a proof of concept thing 
right now. Hopefully, many will like it when it is done.


Manu




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