From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Hacker Date: Fri, 6 May 2011 10:06:07 +0600 Subject: [ath9k-devel] More on signal and noise In-Reply-To: <4DC353A9.3050801@gmail.com> References: <20110503111016.GA23612@infinet.ru> <4DC353A9.3050801@gmail.com> Message-ID: <20110506040607.GA22055@infinet.ru> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org Yes, the AR5416 and so on chips uses the same Athersos CMOS technology and same principle of RSSI/noise measurements. The noise calibration is the process of periodic measuring minimum received power in channel, averaging it and writing back to HW. This averaged value is then used by HW to calculate SNR (rs_rssi). This valie analogues to AR92xx measured in dB to unknown (temperature dependent) reference, not mW. The fact that NF value on ath5k chips is near the real dBm noise level should not lead to conclude that it is the same, it is incorrect. Have a nice day!