How to implement delay element into a circuit?

[magnetra]

In number of digital communication system block diagram, I see a "delay" block. The block is supposed to delay the signal by, lets say Ts time. So how do I implement this block from circuit point of view?

magnetra

 

[eda_wiz]

Delay element

using Flipflops/memory

 

[Davood Amerion]

Delay element

if delay is small you can use 2, 4, .. inverter gates !