Need Urgent Help with Wireless Communication problem

[vonmixer]

Hello,

I'm stuck on this problem, and I need it for an upcoming exam. Any help will be much appreciated.

I'm mainly confused about what the received signal will be at the second antenna.

Thanks

 

[benbo]

Hello,
I'm stuck on this problem, and I need it for an upcoming exam. Any help will be much appreciated.

I'm mainly confused about what the received signal will be at the second antenna.

Thanks

I think this is a phase array antenna or something like that. I think I have an idea how to work this but it is really hard to write out. Probably too late anyway, and I could be totally offbase.

Try this and maybe you can get the answer-

I would convert the f*t term in the argument of the exp function to (j*2*pi*r)/lambda. I’ll call this ARG. This represents the “number of cycles or radians” from the source. Little “r” is the distance from the source. You don’t need to know what it is to solve the problem. To get the composite signal at each antenna you add the signal and the noise. The two signals hit at 90 degrees so they are the same for each antenna = S1(t) = S2(t) = A(t)exp(ARG).

The noise has to “travel” lambda/4 more radians to hit antenna 1 than antenna 2.

So, if you assume a line up the middle, the argument for the N1(t) function is j*2*pi*[(r+(lambda/8))/lambda]. I’ll call this ARGN1.

ARGN2 = j*2*pi*[(r-(lambda/8))/lambda].

So the signals are going to be S(t)+I(t) =

At antenna 1 = A(t)exp(ARG)+N(t)exp(ARGN1)

At antenna 2 = A(t)exp(ARG)+N(t)exp(ARGN2)

Then, you want to weight these and sum them and get back the original signal (eliminate the noise (I(t) portion.

I think there are multiple answers for the weights but W1 = -W2.

Or something like this. The main thing is make that conversion in the argument.

I’d be curious to know if I’m anywhere near close on this. It’s been a LOOOONG time since I did anything like this. Nothing like this on my PE exam or at work.