Frequency selectivity in LTI system

[blade88]

Hi,

I am considering a Linear Time Invariant (LTI) channel model and whether it causes time and frequency dispersion.

Since, LTI systems don't introduce any new frequencies to the output, they don't cause frequency dispersion.

But what about time dispersion?

In wireless communications, multipath causes multiple copies of the signals to reach the receiver with different delays.

Therefore, even if my channel is LTI, still it can cause time dispersion, right?

Some insight would be helpful,

Thank you

 

[bilal_oct]

It's true that LTI system can not create any new frequency component at the output. LTI system can only suppress or enhance the frequency components present in the input signal. They can also cause a delay to the output. Hence, LTI system can only change phase and amplitude of the input signal. Amplitude means gain of the frequency components in the input.