So, I have signal in the waveguide that is transmitted by two modes of radiation, for which the delay is for example $τ1 = 6ns$, $τ2 = 6.5ns$, respectively. And the energy supplied to the receiver by each mode is the same.
My question is about calculating 3dB width of the bandwidth of the channel (containing the constant component - but I'm not sure what that means). I know I need to substract this two modes one from the other (with an absolute value):
$d = ABS(6ns - 6.5ns)$
$d = 0.5$
And next I multiply my $d*2$ and divide one by my result. So:
Ant this gives me $1GHz$, and this is perfectly correct anser! But I don't know why this formula works, why we don't use the lambda formula for our waveguide frequency? And what does it mean that the channel was created in the basic band? I have a problem understanding this. Thank you in advance for your help.