Arc Discharge Noise
Because an electric arc is a conduction channel that forms and collapses in a very short time, it is by nature a broadband noise source. A welding machine arc, contactor sparking and brush arcing all work by the same mechanism. Since it is amplitude in character, it particularly disrupts links using amplitude-based modulation.
Arc current flows as irregular pulses; because the rise times of these pulses are very short, the spectrum produced spreads over a wide range. At the receiver this appears as short but high-amplitude noise pulses.
- Amplitude-based links: since ASK and OOK receivers decide on amplitude, they may mistake these pulses for data.
- Frequency-based links: FSK and its variants are less sensitive to amplitude fluctuations, but if the pulse is strong enough the packet is still corrupted.
- Recovery: a corrupted packet is discarded at the checksum test; the next attempt usually passes, so the symptom is stuttering rather than a dropout.
On the prevention side: fitting suppression components on contactor coils, using arc suppression on relay contacts, keeping the welding machine's chassis return path short and direct, and moving the receiver antenna away from the arc zone are all effective.
Context in which this term is used: Wireless remote control installation: pairing, relay, safety