Thanks for confirming the HVR-955Q SNR and other data is available via
the DVBv5 API.
Before switching my signal/antenna test programs to DVBv5, 'll see if
I can figure out why the dvb-fe-tool is not returning the SNR data and
error rate statistics from the HVR-955Q even though it does return
this info from other Hauppauge USB tuners like the Aero-M. Perhaps I
missed an update.
I may be back with more questions!
...Doug
On Mon, Jun 8, 2015 at 1:59 AM, Antti Palosaari <crope@xxxxxx> wrote:
> Moikka!
>
>
> On 06/08/2015 01:21 AM, Doug Lung wrote:
>>
>> Hello! this is my first post here, although I've benefited from all
>> the work of the contributors over the year. Thanks!
>>
>> I'm looking for help getting similar signal statistics from the new
>> Hauppauge HVR955Q (Si2157, LGDT3306A, CX23102) USB ATSC tuner that I'm
>> now getting from the Hauppauge Aero-M (MxL111SF, LGDT3305). I'm
>> currently using DVBv3 API in my programs but am open to switching to
>> the DVBv5 API if necessary.
>>
>> I applied Antti Palosaari's "si2157: implement signal strength stats"
>> patch to the media_build and dvb-fe-tool with dvbv5-zap now returns
>> relatively accurate RSSI data in dBm from the HVR955Q but no SNR or
>> packet error data. dvb-fe-tool provides a full set of data
>> (unformatted) from the Aero-M but only Lock and RSSI (formatted in
>> dBm) from the HVR955Q.
>>
>> The SNR and packet error data is available from the HVR955Q in raw
>> form in DVBv3 applications like femon. The Si2157 RSSI in dBm is not.
>> The DVBv3 apps show the "signal quality" based on SNR margin above
>> threshold from the LGDT3306A.
>>
>> Any suggestions on modifying the HVR955Q driver to provide RSSI
>> (unformatted is okay) from the Si2157 with the DVBv3 API? That's
>> preferred since it will work with my existing Aero-M signal testing
>> programs.
>>
>> Alternatively, is there a way to obtain full DVBv5 API compliant
>> signal quality data (RSSI, SNR, uncorrected packets) from the
>> HVR955Q's LGDT3306A so I can modify my programs to use the linuxdvb.py
>> API v5.1 bindings?
>
>
> Looking the LGDT3306A code reveals it already calculates SNR as dB, so
> returning it via DVBv5 is easy.
>
> BER and UCB are returned as a raw error values from registers. You could
> return those also as a error values by counter type easily (numerator of
> fraction). But getting some useful values you will need also total number of
> packets too (denominator) (error fraction = error count / total count).
> Total count is not mandatory, but very recommend, you have to find it some
> how, calculate from stream parameters for example.
>
>
> regards
> Antti
>
> --
> http://palosaari.fi/
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