[mythtv] Re: Re: [mythtv-commits] Re: Ticket #339: Simplify Tuning process

Mac Michaels wmichaels1 at earthlink.net
Thu Sep 22 16:07:59 UTC 2005


The lgdt330x chips do not provide signal strength data. It 
might be possible to compute signal strength from the 
automatic gain control (AGC) data, but the spec sheet does 
not provide a formula. As a result the signal strength is 
always set to 0.

Data is available from which the signal to noise ratio (snr) 
can be calculated. The driver currently returns raw data 
since the unsigned 16 bit return value it not appropriate 
for returning the actual snr in db. Snr must be signed 
because it is negative when the signal is less than the 
noise and positive when the signal is greater than the 
noise.

--Mac

On Thursday 22 September 2005 09:53 am, David Engel wrote:
> On Thu, Sep 22, 2005 at 10:42:16AM -0400, Taylor Jacob 
wrote:
> > Many drivers just report arbitrary vaules that have no
> > unit because the author did not have the datasheet, and
> > this will not change.. Not even if all manufacturers of
> > demodulators decide to support linux for some reason..
>
> FWIW, my Fusion HDTV5 always reports 0 for signal level.
>
> David


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