I will state here what I understand in this topic which I am a little confused:(adsbygoogle = window.adsbygoogle || []).push({});

If I have 2 sinusoidal signals perfectly in phase, with distinct power levels, say -13dBm and -10dBm, the composition ("sum") of both signals is -8.23dBm. Or, for -10dBm and -10dBm signals, the sum is -7dBm.

Now, if one signal which lags around 180 degrees in relation to the other signal, the composition of both signals is almost 0 (a very low value in dBm, say -300dBm) because there is a cancellation of signals.

But, for different values of this delay-angle (difference between signal phases), it is expected a huge variation of the signal composition.

In the mentioned example, the variation is from -8.23 dBm to -infinite dBm (no signal).

I would like to:

(1) confirm if I am correct with my explained reasoning. If not, please, express your argument with numbers of this example.

(2) get a hint about where I can find theoretical material with the formula for such signal composition (assume sinusoidal signal with different amplitudes) or the formula itself. However, I need to maintain the notation in dBm (assume fixed load impedance). Using cos function, we can measure the phase delay with values from -1 to 1. Now, how to plug this in the original problem?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Signal Composition: in-phase and not-in phase

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**