Sample Rate and Discrete Frequency

An ADC samples a continuous-time signal to produce discrete-time samples. From the viewpoint of a digital signal processor, this signal is represented in computer memory as a series of numbers. Unless the sample rate $f_s$ is known, there’s little that can be done.

Determining the frequency

With the available information about $f_s$, we can discover the frequency by first computing the period. For example, the figure below shows a discrete-time sinusoid with a period of $20$ ...