From: Antti Palosaari <crope@iki.fi>
To: James <bjlockie@lockie.ca>
Cc: linux-media Mailing List <linux-media@vger.kernel.org>
Subject: Re: femon patch for dB
Date: Sun, 30 Oct 2011 17:42:25 +0200 [thread overview]
Message-ID: <4EAD7061.3020007@iki.fi> (raw)
In-Reply-To: <4EAB342F.2020008@lockie.ca>
On 10/29/2011 02:01 AM, James wrote:
> I added a switch to femon so it displays signal and snr in dB.
>
> The cx23885 driver for my Hauppauge WinTV-HVR1250 reports signal and snr
> in dB.
>
> http://lockie.ca/test/femon.patch.bz2
from patch:
human readable output: (signal: 0-65335, snr: 1/256 increments)\n"
human readable output: (signal and snr in .1 dB increments)\n"
You should take look to demod drivers and check what those are
returning. I have strong feeling that most drivers returns SNR as 10xdB.
And SS as 0-0xffff. I think there is good consensus of SNR unit, but for
SS it is not so clear. For my drivers I have used SNR 10xdB and SS
0-0xffff. That's why, giving only those two alternatives is not
suitable. Maybe it is better to set own param for SNR and SS?
Devin did some research about SNR long time back:
http://www.devinheitmueller.com/snr.txt
regards
Antti
--
http://palosaari.fi/
prev parent reply other threads:[~2011-10-30 15:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-28 23:01 femon patch for dB James
2011-10-29 0:21 ` Marek Vasut
2011-10-29 2:12 ` Randy Dunlap
2011-10-29 5:12 ` James
2011-10-29 5:39 ` Randy Dunlap
2011-10-29 6:37 ` Mauro Carvalho Chehab
2011-10-30 13:52 ` Michael Krufky
2011-10-30 14:01 ` Michael Krufky
2011-10-31 16:42 ` James
2011-10-30 16:21 ` VDR User
2011-10-30 15:42 ` Antti Palosaari [this message]
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