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Design >> RF Design >> sensitivity of lna
https://designers-guide.org/forum/YaBB.pl?num=1320408149

Message started by chris2312 on Nov 4^th, 2011, 5:02am

Title: sensitivity of lna
Post by chris2312 on Nov 4^th, 2011, 5:02am

Hello,

I want to calculate or simulate the power of the minimum detectable signal of a LNA, but I have no idea how to get it. I have data of simulated noise figures of the lna, but I think that I only can calculate it with assumption of a special SNR of the signal or could I calculate/simulate it otherwise ? Thanks for response.

Title: Re: sensitivity of lna
Post by loose-electron on Nov 5^th, 2011, 12:53pm

minimum detectable?

At what channel BW, SNR, or what BER?

A little more info on what you are looking for please.

Title: Re: sensitivity of lna
Post by chris2312 on Nov 8^th, 2011, 6:43am

Yes the minimum detectable signal, which could be handled with the LNA. I have a dualband-LNA at 5.8 GHz and 2.4 GHz and it reaches a NF of 3.4 dB and 3 dB. What do you need ? The channel BW ist 150 MHz and 100 MHz repectively. About the SNR that was also a question. Do I have to assume a special SNR to calculate it ? Thanks.

Title: Re: sensitivity of lna
Post by raja.cedt on Nov 8^th, 2011, 8:02am

hello,
SNR depends on the BER you are intersted at the o/p and BER specified by the standard

Thanks,
raj.

Title: Re: sensitivity of lna
Post by loose-electron on Nov 8^th, 2011, 11:01am

Minimum detectable sounds more like a marketing term - need the defined SNR - BER to define this.

Title: Re: sensitivity of lna
Post by wave on Nov 8^th, 2011, 1:27pm

MDS is common in some types of systems. Closely related to SNR.

http://en.wikipedia.org/wiki/Minimum_detectable_signal

Title: Re: sensitivity of lna
Post by aaron_do on Nov 13^th, 2011, 5:23pm

Hi,

by minimum detectable signal, you probably mean the sensitivity. But that depends on the rest of your system. As far as I know, NF is usually enough for an LNA only. Of course if you want to specify sensitivity as limited by interference, you also need IIPn.

If you really want to know the sensitivity due to the LNA alone, its just the noise floor plus the NF plus the required SNR to meet BER specifications.

regards,
Aaron

Title: Re: sensitivity of lna
Post by loose-electron on Nov 14^th, 2011, 10:00am

Yes the SNR and BER question - but no response to whats needed...