The question about signal power in watts

Hi guy, I am trying to use the AWGN Channel in the Simulink. Previously, I used awgn(y,SNR,'measured') in the Matlab. Now I need to set the input signal power (referenced to 1 ohm watts) in the block parameters. I am not familiar with this unit. For example, how much is the power of the signal y = 1*sin(t) in the watts?

My question is: how to calculate the signal power in watts, and how to setup the parameter in AWGN Block in Simulink? Thanks

Answer 1

[Honglei Chen]

I assume your signal, y, is the voltage signal in volts, and the load is 1ohm, then the power is 0.5 watts

Here is an example for calculation of power via psd

fs = 1000;
x = sin(2*pi*10*(0:999)/fs);
hpsd = psd(spectrum.periodogram,x,'Fs',fs);
avgpower(hpsd)

[Jiazeng Shan]

Thank you for your reply. Your example helps me to understand. However, if the signal is in the acceleration unit (m/s^2), how do I set the parameter (signal power in watts) in the AWGN block?

[Honglei Chen]

I'm not sure if I understand your question. In general, the acceleration is converted to a voltage signal through sensor so what you process is in volts. I think this is a fair assumption to make and does not lose any generality.

Answer 2

[saikiran]

From the examples provided i figured it to be 1/(2*Eb/No), Is it true?