When db is came?

The term "db" typically refers to "decibel," a unit of measurement for sound intensity and other quantities. The concept of the decibel was developed in the early 20th century, with significant contributions from engineers like Alexander Graham Bell. It was later formalized in the 1920s by the Bell System for telecommunications applications. The decibel scale is logarithmic and has since become widely used in various fields, including acoustics, electronics, and telecommunications.