One application needed to divide the signal to obtain 20 percent of the actual signal. Therefore I post some sites.
Multiplication-by-a-Fixed-Point-Constant [eetimes.com/]
[www.cs.uaf.edu/~cs301/notes/]
Multiplying-normalized-16-bit-numbers [ssp.impulsetrain.com]
Division
Fast-Faster-Fastest-Code-Integer-division [forums.parallax.com]
Division-of-integers-by-constants [embeddedgurus.com]
Reciprocal multiplication [homepage.cs.uiowa.edu]
Well explained how to use fixed point arithmetic
Division [hackersdelight.org]
Pdf document