A skilled operator might only be able to distinguish a signal 3 db above the noise floor s n 3 db or 75 dbm.
Current noise floor.
19 in video systems a 50 db signal to noise ratio is a generally.
Generally measured in db of its maximum undistorted output signal to its residual output noise or noise floor up to 120 db of dynamic range may be required in high performance sound systems in typical homes.
A typical radar receiver would require a s n of 3 to 10 d b to distinguish the signal from noise and would require 10 to 20 db to track.
Analyzing noise in general can be difficult as there are a variety of intrinsic noise sources and these intrinsic noise sources are unique to different systems.
Noise is naturally stronger with decreasing frequency and s meters are rarely calibrated to any standard so a s7 noise floor on 40 meters may just be ordinary.
The noise floor will naturally go up as the band opens at night as you are able to hear more distant natural and man made noise sources.
In radio communication and electronics this may include thermal noise black body cosmic noise as well as atmospheric noise from distant thunderstorms and.
In signal theory the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system where noise is defined as any signal other than the one being monitored.