Formula for Gain Decibels?

Gain is defined as the ratio of the output power to the input power in dB. Assume that the input power is 10 mW (+10 dBm) and the output power is 1 W (1000 mW, +30 dBm). The ratio will be 1000/10 = 100, and the gain will be 10 * log 100 = 20 dB.

What is the gain in decibels?

Gain in dB is the logarithmic ratio between the output and input voltage of the preamplifier. Typical values lie between 0 and 70 dB. Gains and losses may be expressed in terms of a unitless ratio, or in the unit of decibels (dB).

What does a gain of 20 dB represent?

For power, doubling the signal strength (an output-to-input power ratio of 2:1) translates into a gain of 3 dB; a tenfold increase in power (output-to-input ratio of 10:1) equals a gain of 10 dB; a hundredfold increase in power (output-to-input ratio of 100:1) represents 20 dB gain.