What does the decibel (dB) measure in relation to signal transmission?

The decibel (dB) is a logarithmic unit used to express the ratio of two values, particularly in the contexts of power and intensity. In terms of signal transmission, it specifically measures relative signal gain or loss. This means it can indicate how much stronger or weaker a signal has become as it travels through a medium, such as a cable or through the air.

For instance, a positive dB value indicates an increase in signal strength (gain), while a negative dB value indicates a decrease in signal strength (loss). This is particularly useful in telecommunications and networking, where understanding the relative changes in signal levels along the transmission path is crucial for maintaining effective communication systems.

In contrast, absolute signal strength refers to a specific measurement of power at a certain point, which is not what dB measures; rather, it focuses on the comparison of signal levels. Electrical resistance, on the other hand, relates to the opposition to the flow of electric current, and frequency deals with how often a signal oscillates. These concepts do not directly pertain to what the decibel measures within signal transmission contexts.