## Discrete systems in series

We have two discrete systems, and their impulse responses are h1(n) and h2(n). Then when these discrete systems are connected in series, then overall impulse response:

Where:

As you noticed there were changing made:

This is nothing more than convolution of impulse responses of both discrete systems:

## Discrete systems in parallel

If we have two discrete systems connected in parallel:

As we see, there is a simple sum of output queues of each discrete system. So we can assume, that the overall impulse response is the sum of systems connected in parallel: