A clock is a signal that provides a timing reference to digital circuits by generating a regular binary square wave. It consists of:
The clock frequency (Hz), which determines how fast the system can operate, with higher frequencies allowing for faster processing but increasing power consumption and heat. The clokc frequency can be also interpreted as rising edges per second.
The clock period (T=f−1seconds), represents the duration of one complete cycle of the clock signal, or simply put between two rising edges.
\begin{document}\begin{tikzpicture}[scale=1.25, transform shape] % Draw the waveform \draw[thick] (0,0) node[left, at start] {t=0} -- (1,0) -- (1,1) -- (3,1) -- (3,0) -- (5,0) -- (5,1) -- (7,1) -- (7,0) -- (9,0); % Label the rising edge \draw[red, thick] (1,0.5) circle [x radius=0.1, y radius=0.6]; \node[red, below, align=center] at (1, -0.1) {Rising \\ Edge}; % Label the falling edge \draw[blue, thick] (3,0.5) circle [x radius=0.1, y radius=0.6]; \node[blue, below, align=center] at (3, -0.1) {Falling \\ Edge}; % Label the period \draw[<->, thick, green!50!black] (3, 1.5) -- (7, 1.5) node[midway, above] {Period};\end{tikzpicture}\end{document}