Re: SNR status for demods
Just ping up old thread since I updated that list. On 18.03.2009 04:45, Devin Heitmueller wrote: Hello all, I have updated my compiled list of the various demods and how they currently report SNR info (including feedback from people in the last round). http://www.devinheitmueller.com/snr.txt I updated that list up to that day: http://palosaari.fi/linux/v4l-dvb/snr_2012-05-21.txt Here's how you can help out: If you are a maintainer for a device in this list, please let me know so I can update the document. If you are the maintainer and somebody else's name is listed by the device, please do not take offense to this (it's probably just an error on my part [please email and correct me]). If you have specs for a device in this list where the format is currently unknown, please let me know as this will be helpful in identifying which demods we can get accurate information for. If you know something about how SNR is currently reported by the driver, and it is not reflected in this list, please let me know and I will update the document. All of the above information will be helpful once a format has been decided on, so we can pull together and finally get a consistent interface. Thank you for your time, Devin Basically, but not every case, there seems to be 3 different way: 1) return raw register value without any calculation 2) 0.1 dB 3) scaled to 0-0x using some formula Very many drivers seems to do some dB handling even finally scaling it to some value. regards Antti -- http://palosaari.fi/ -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: SNR status for demods
Il 22/05/2012 11:09, Antti Palosaari ha scritto: Basically, but not every case, there seems to be 3 different way: 1) return raw register value without any calculation 2) 0.1 dB 3) scaled to 0-0x using some formula Very many drivers seems to do some dB handling even finally scaling it to some value. regards Antti Another one (from staging): as102-fe.c:Pierrick Hascoet, Devin Heitmuellerlinear MER I can provide a trivial patch to convert it to the more common 0.1 dB format, if you think it's useful. This note comes from the driver: /* * Note: * - in AS102 SNR=MER * - the SNR will be returned in linear terms, i.e. not in dB * - the accuracy equals ±2dB for a SNR range from 4dB to 30dB * - the accuracy is 2dB for SNR values outside this range */ Regards, Gianluca -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: SNR status for demods
I have updated my compiled list of the various demods and how they currently report SNR info (including feedback from people in the last round). http://www.devinheitmueller.com/snr.txt What about signal strength and BER readout in parallel for each device listed here? Needs the same docs and would not add too much work.. tda10021: MSE[7..0] (= reg 0x18 ) Mean Square Error of the demodulated output signal. MSE can be used as a representation of the signal quality. u8 quality = ~tda10021_readreg(state, 0x18); *snr = (quality 8) | quality; ves1820:the same. tda10023: seems to be the same. (no info, but chip is very close to tda10021) -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
SNR status for demods
Hello all, I have updated my compiled list of the various demods and how they currently report SNR info (including feedback from people in the last round). http://www.devinheitmueller.com/snr.txt Here's how you can help out: If you are a maintainer for a device in this list, please let me know so I can update the document. If you are the maintainer and somebody else's name is listed by the device, please do not take offense to this (it's probably just an error on my part [please email and correct me]). If you have specs for a device in this list where the format is currently unknown, please let me know as this will be helpful in identifying which demods we can get accurate information for. If you know something about how SNR is currently reported by the driver, and it is not reflected in this list, please let me know and I will update the document. All of the above information will be helpful once a format has been decided on, so we can pull together and finally get a consistent interface. Thank you for your time, Devin -- Devin J. Heitmueller http://www.devinheitmueller.com AIM: devinheitmueller -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: SNR status for demods
Thank you very much, Devin Heitmueller. This list is a god-sent :). Devin Heitmueller wrote: Hello all, I have updated my compiled list of the various demods and how they currently report SNR info (including feedback from people in the last round). http://www.devinheitmueller.com/snr.txt Here's how you can help out: If you are a maintainer for a device in this list, please let me know so I can update the document. If you are the maintainer and somebody else's name is listed by the device, please do not take offense to this (it's probably just an error on my part [please email and correct me]). If you have specs for a device in this list where the format is currently unknown, please let me know as this will be helpful in identifying which demods we can get accurate information for. If you know something about how SNR is currently reported by the driver, and it is not reflected in this list, please let me know and I will update the document. All of the above information will be helpful once a format has been decided on, so we can pull together and finally get a consistent interface. Thank you for your time, Devin -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
