- #1

- 6

- 0

## Homework Statement

Two receivers, d=5 [meters] apart, are recording an air wave signal.

The air wave travels in v=330 [m/sec] and coming from one side of the receivers.

The air wave contains all the frequencies between 10 [Hz] and 200 [Hz].

a) If we

**sum up**the recorded signal from the two receivers, does all the energy from the original wave will be conserved ? explain.

b) The sampling rate in the receivers is Δt=0.004 [Sec], sketch the amplitude spectrum of the sum series.

## Homework Equations

[itex]$\omega =2\pi f$[/itex] ,

[itex]\[\sum\limits_{n=0}^{N-1}{|}{{x}_{n}}{{|}^{2}}=\frac{1}{N}\sum\limits_{k=0}^{N-1}{|}{{X}_{k}}{{|}^{2}}\][/itex] (Parseval Theorem)

and maybe the DFT of sin/cos functions

## The Attempt at a Solution

a) I know that the starting point should be the distance and the velocity.

so we get t=v/d and from that the frequency can be calculated somehow.

also the wave is a combination of known sin waves, so after DFT it transfers into a delta function.

b) Here i don't even know how start, since nothing is implied about the amplitude !