Difference between Nyquist rate and Nyquist frequency? So I've been searched online and can't seem to find a clear cut answer to this question.

From my understanding, the Nyquist rate is double of the maximum frequency of a signal which Nyquist frequency is half of the Nyquist rate.

Which would conclude that Nyquist rate is the lower bound of sampling and Nyquist frequency would be the upper bound where Nyquist rate is where you can preserve the original signal and anything in between the Nyquist rate to Nyquist frequency would cause some aliasing.

Is this correct?
Harry Nyquist invented/discovered/proved a lot of things; it can be hard to keep track of them all. The three most important for signal processing and communications are probably these:


If you sample a (real) signal $s(t)$ at $f_s&gt;2B$ samples per second, then $s(t)$ can be reconstructed from its samples, where $B$ is the bandwidth of $s(t)$. The lower bound $2B$ is often called the Nyquist rate.
If you sample a signal $s(t)$ at $f_s$ samples per second, then $f_N=f_s/2$ is frequently called the Nyquist frequency (also folding frequency). All frequencies in $s(t)$ higher than $f_N$ will be aliased back to a frequency between 0 and $f_N$.
Assume you have a baseband channel of bandwidth $B$ (that is, signals with bandwidth $B$ or less are not distorted by the channel). This channel allows transmission of a maximum of $2B$ orthogonal pulses per second. $2B$ in this context is also called the Nyquist rate.