Re: SNR status for demods

[Antti Palosaari <crope@iki.fi>]

Just ping up old thread since I updated that list.

On 18.03.2009 04:45, Devin Heitmueller wrote:
> Hello all,
>
> I have updated my compiled list of the various demods and how they
> currently report SNR info (including feedback from people in the last
> round).
>
> http://www.devinheitmueller.com/snr.txt

I updated that list up to that day:
http://palosaari.fi/linux/v4l-dvb/snr_2012-05-21.txt

> Here's how you can help out:
>
> If you are a maintainer for a device in this list, please let me know
> so I can update the document.  If you are the maintainer and somebody
> else's name is listed by the device, please do not take offense to
> this (it's probably just an error on my part [please email and correct
> me]).
>
> If you have specs for a device in this list where the format is
> currently "unknown", please let me know as this will be helpful in
> identifying which demods we can get accurate information for.
>
> If you know something about how SNR is currently reported by the
> driver, and it is not reflected in this list, please let me know and I
> will update the document.
>
> All of the above information will be helpful once a format has been
> decided on, so we can pull together and finally get a consistent
> interface.
>
> Thank you for your time,
>
> Devin
>

Basically, but not every case, there seems to be 3 different way:
1) return raw register value without any calculation
2) 0.1 dB
3) scaled to 0-0xffff using some formula

Very many drivers seems to do some dB handling even finally scaling it 
to some value.

regards
Antti
-- 
http://palosaari.fi/