what happens if I put two non coherent signals as inputs of a combiner?

[Shirai]

If I input a signal whose transmission S-parameter ( S21 ) ( the previous stage was a two port network ) is 0.5<20 degrees with a signal 0.5<100 will my output be just the addition ? ( simple addition ) and thus will decrease in amplitude or the loss is independent of the sum answer ( ratio of input to output ) ?

 

[FvM]

The signal specification seems at least incomplete. Incoherent means both signals have different frequency and/or arbitrary phase relation. They add in the combiner by their instantaneous voltage, e.g. out-off-phase signals are substracted or can even cancel each other.