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Below are all of the forum threads, including all the responses to the original posts. venkataravi Post subject: Relationship between Resolution Bandwidth and Recived signal Posted: Mon Sep 25, 2006 4:04 am Captain Joined: Thu Jul 27, 2006 7:36 am Posts: 11 Location: Bangalore --India Hi, What is the relationship between Resolution Bandwidth and Received signal strength. With Regards Y.V.Ravi Top IR Post subject: Posted: Mon Sep 25, 2006 1:25 pm Site Admin Joined: Mon Jun 27, 2005 2:02 pm Posts: 373 Location: Germany There is no relationship as the RSSI deals with amplitude and the Resolution BW deals with frequency _________________ Best regards, - IR Top frmunder Post subject: Posted: Mon Sep 25, 2006 6:10 pm Lieutenant Joined: Mon Sep 25, 2006 5:52 pm Posts: 2 As IR stated, there is not a direct relationship; but having a large resolution bandwidth can make the noise power swamp a low level signal. Noise power in a 1hz bandwidth is -174dBm. Increase your bandwidth, and your noise grows by 10*log(RBW). So if your resolution bandwidth is 10MHz, your noise power is -174dBm+10*log(10,000,000)=-107dBm. If your signal is smaller than this level, it will be unrecognizable. (For different modulation formats, you also need to add more power to demodulate, i.e. C/N) To be able to "see" this signal, you must decrease your bandwidth (as long as your signal can be processed in the decreased bandwidth). Top IR Post subject: Posted: Tue Sep 26, 2006 4:14 pm Site Admin Joined: Mon Jun 27, 2005 2:02 pm Posts: 373 Location: Germany That is true, but if you want to see the whole picture then you shouldn't forget the tempearture contribution to the noise power: Pn=KTB Where: K - Boltzmann's contasnt 1.38*10e-23 J/Kelvin T - Relative temperature in Kelvin B - The bandwidth In logarithmic terms, this formula becomes: Pn=-174dBm+10 log (T/To) + 10 log BW So any temperature above To (290 Kelvin degrees=17 deg C) will also increase the noise power, and according to the explanation given above will limit the strength of the received signal. So in conclusion RSSI is not related just to the BW, but also to surrounding temperature... _________________ Best regards, - IR Posted 11/12/2012 | ||||||
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