External sound contains any type of exterior influences, including external parts and electrical/electromagnetic interference. Interference is defined as any unwelcome alerts arriving as both voltage or current, at any of your amplifier’s terminals or induced in its linked circuitry. It could appear as spikes, techniques, sine waves, or random noise. https://low-noiseamplifier00100.dailyhitblog.com/42697852/the-basic-principles-of-low-noise-amplifier