Sugarcane farm

Hi all,
I am trying to figure out how to make a sugar cane farm but to do so I need to know more about redstone clocks. I can understand the principals of why what I am doing works but when you put redstone next to a redstone torch how come that allows for a alternating pulse?

By placing a redstone wire next to a powered redstone torch, the wire receives a redstone signal and powers any adjacent components. However, as soon as the redstone signal reaches the torch, the torch turns off, breaking the circuit and stopping the signal from traveling any further. This causes the wire to lose power, and the adjacent components to turn off.