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Baseband Equivalent RF Transceiver (Read 3221 times)
uncle_ezra
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Baseband Equivalent RF Transceiver
Mar 28th, 2005, 2:33am
 
Hi,

I have a question related to amplifier noise modeling in simulink. So for Noise I am basically calculating the noise power (equation below) of the amplifier itself and using the Bandlimited White Noise provided in simulink

Noise_Power=(10^(0.1*NF) - 1) * 10^(0.1*Gain) * 2*4*k*T*R
NF=Noise Figure in dB
Gain=Gain of the amplifier in dB

Basically I add the input signal with the Bandlimited White Noise. Is this a reasonable model?  If not how would you recommend I model Noise Figure.

Thanks
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hjee
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Suwon, South Korea
Re: Baseband Equivalent RF Transceiver
Reply #1 - Sep 27th, 2005, 7:41pm
 
Basicly, it's better to know the noise model is input equivalent or output equivalent.
Then you'd better to declare the match impedence R to generate the noise pwr 4kRT - which is also referred to source noise.
noise factor = SNR|output / SNR|input
noise figure(NF) = 10*log(noise factor)
SNR|output = S|input * Gain^2 / N|input+N|amp_output
SNR|input   = S|input/N|input

=> noise factor = Gain^2*N|input / (N|input+N|amp_output)

Up to now, we can model or derive the output equivalent noise N|amp_output

At last, we can also derive the input equivalent noise,
N|input = N|amp_output / Gain^2

Above is the basic noise modeling for LNA in RF receiver.


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