Linear gain in a chain of cascaded components is by far the easiest parameter to calculate.
Because its value is a firstorder entity with no dependence on any other parameter of a particular
component (assuming no signal feedback or leakage), combining gain two successive stages is
the simple addition of each stage's gain if expressed in units of dB, or multiplication if
expressed as a unitless ratio.
Click here to view an example of a cascaded system. 
For example, if a 1st and 2nd stage in a cascade have power (as opposed to voltage) gains
of 3.01 dB (multiplication factor of 2) and 10.0 dB (multiplication factor of 10), respectively,
then the total gain is:
3.01 + 10.0 = 13.01 dB,
or a multiplication factor of:
2 x 10 = 20 [check:
10 * log_{10} (20) = 13.01 dB].
It's that simple!
A Typical Chain of Cascaded Components
Combining 2 Stages at a Time for Calculations
