Obtain Si2157 and LGDT3306A signal stats from HVR955Q?

Obtain Si2157 and LGDT3306A signal stats from HVR955Q?

[Doug Lung]

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?

      ...Doug Lung

Re: Obtain Si2157 and LGDT3306A signal stats from HVR955Q?

[Antti Palosaari]

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/

Re: Obtain Si2157 and LGDT3306A signal stats from HVR955Q?

[Doug Lung]

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@iki.fi> 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/