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From: | Marcus D. Leech |
Subject: | Re: [Discuss-gnuradio] Measure the power using USRP |
Date: | Mon, 07 Dec 2015 21:53:02 -0500 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 12/07/2015 09:34 PM, w xd wrote:
Hi, I want to measure the power.I'm now transmit the OFDM signal.I use the usrp to receive data,and I save it to a file.I read all the data.Then:I use the formula to calculate the power: 10*log10(sum(abs(data).^2)/0.001) dbm Is it the right way to calculate the power under the ofdm? Thanks. Best Regards, z sw
Instantaneous signal power is proportional to: (I**2)+(Q**2)You can average that to whatever interval you want, and then scale (perhaps converting into dB, as above). But to determine *absolute* power at the antenna terminals you'll need a known calibration source or two, and use that to come up with calibration constants for
your particular setup of frequency/gain/bandwidth/sample-rate.
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