From: Anssi Hannula <anssi.hannula@gmail.com>
To: Thierry Lelegard <thierry.lelegard@tv-numeric.com>
Cc: linux-dvb@linuxtv.org
Subject: Re: [linux-dvb] Interpretation of FE_READ_BER
Date: Mon, 31 Mar 2008 02:27:39 +0300 [thread overview]
Message-ID: <47F021EB.6010104@gmail.com> (raw)
In-Reply-To: <!~!UENERkVCMDkAAQACAAAAAAAAAAAAAAAAABgAAAAAAAAAJf2pBr8u1U+Z+cArRcz8PMKAAAAQAAAASuTAGpqJw0asMd7tD3VNFwEAAAAA@tv-numeric.com>
Thierry Lelegard wrote:
> Hi,
Hi! I'm not an expert in this matter, but it seems no one else is replying.
> What is the interpretation of the value returned by ioctl FE_READ_BER?
AFAIK the exact meaning of all the values is driver/device-specific.
> Normally, a bit-error-rate is something like 10^-6 (typically not an
> integer value).
>
> There is no clue in the Linux DVB API doc. Google reports similar
> questions but none with an answer. I have just seen one note suggesting
> it could be a multiple of 10^-9. Looks good to me but since there is
> no good definition of this parameter in the docs, I wonder if drivers
> implement them in a consistent way.
I don't think so.
> With my Nova-T 500 (Fedora 8, kernel 2.6.24.3-12, recent v4l hg tree),
> the reception is quite fine, FE_READ_SIGNAL_STRENGTH returns 40000 (60%),
> but FE_READ_BER always returns 0. Does this mean "not even the slightest
> error" (to good to be true), "not supported" (should return errno ENOSYS),
> "driver bug"?
0 can very well mean there is no errors, it is not that uncommon (I've
seen it with my devices in good conditions).
--
Anssi Hannula
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next prev parent reply other threads:[~2008-03-30 23:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-27 10:49 [linux-dvb] Interpretation of FE_READ_BER Thierry Lelegard
2008-03-30 23:27 ` Anssi Hannula [this message]
2008-04-08 20:12 ` Morgan Tørvolt
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