When transmitting a data signal over a channel with random thermal noise, the data transmission rate Rmax is related to the channel bandwidth B and the signal-to-noise ratio S/N as follows: Rmax=B*LOG⒉(1+S/N)
In the related fields of signal processing and information theory, a well-known formula called Shannon's theorem has been obtained after investigating how signals attenuate after a distance and how much data can be loaded on a given signal. a famous formula called Shannon's theorem. It gives an upper limit to the speed of a link in bits per second (bps), expressed as a function of the signal-to-noise ratio of the link, which is measured in decibels (dB). Thus we can use Shannon's theorem to detect the data rate of a telephone line.
Shannon's theorem is given by the following formula: C=Blog2(1+S/N) where C is the available link speed, B is the bandwidth of the link, S is the average signal power, N is the average noise power, signal-to-noise ratio (S/N) is usually expressed in decibels (dB), the number of decibels = 10 × log10 (S/N).
Specifically, you can check the university textbook of computer network engineering program<<Computer network technology>>