From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:47025 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753967AbaI2OMz (ORCPT ); Mon, 29 Sep 2014 10:12:55 -0400 Message-ID: <542968E4.6020308@iki.fi> Date: Mon, 29 Sep 2014 17:12:52 +0300 From: Antti Palosaari MIME-Version: 1.0 To: Bimow Chen , linux-media@vger.kernel.org Subject: Re: [PATCH 1/2] af9033: fix signal strength value not correct issue References: <1411980225.1747.10.camel@ite-desktop> <54294A66.30703@iki.fi> In-Reply-To: <54294A66.30703@iki.fi> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On 09/29/2014 03:02 PM, Antti Palosaari wrote: > On 09/29/2014 11:43 AM, Bimow Chen wrote: >> Register 0x800048 is not dB measure but relative scale. Fix it and >> conform to NorDig specifications. > > eh, 0x800048 register returned strength normalized to 0-100 %. But that > was earlier when older firmwares used. I have seen it does not return > anything anymore, so I am very fine it is replaced with something > meaningful. > > But the issues is that this patches changes current DVBv5 signal > reporting from dBm to relative. I indeed implemented it is as a dBm and > I checked it using modulator RF strength it really is dBm. Now you add > some glue which converts dBm to relative value between 0-0xffff. > > I encourage you to use modulator yourself to generate signals. Then use > dvbv5-zap to see values DVBv5 API reports. > > If you really want return 0-0xffff values, then do it for old DVBv3 > read_signal_strength(), but do not change new DVBv5 statistics to > relative. dBm, as a clearly defined unit, is always preferred over > relative. Relative was added to API for cases we cannot report well > known units. > > Could you tell which is unit NorDig specification defines for signal > strength? According to latest NorDig specification, page 39 http://www.nordig.org/pdf/NorDig-Unified_ver_2.5.1.pdf there is two kind of reports, basic and advanced. Normal report is (%) which suits well for relative scale. The basic status check shall include: * channel id, according to Annex B.2 * centre frequency * Signal Strength Indicator, SSI (%), according to section 3.4.4.6 * Signal Quality Indicator, SQI (%), according to section 3.4.4.7 The terrestrial NorDig IRD should provide an advanced status check function (accessible through the Navigator) that presents the following information: * channel id, according to Annex B.2 * centre frequency * signal strength (dBm or dBμV) * signal strength indicator, SSI (%), according to section 3.4.4.6 * signal quality indicator, SQI (%), according to section 3.4.4.7 * C/N (dB) * BER before Reed Solomon decoding (DVB-T) or BCH decoding (DVB-T2) * Uncorrected packets regards Antti -- http://palosaari.fi/