Ambient Noise/ Ambient EME is composed of numerous sources of which the most significant are –

• Television transmissions
• Solar Magnetic Storms which peak on a eleven year cycle.
• Lightning which occurs as a very high voltage and high current event
• Utility power grid transmission lines.
• Other ambient EME sources include airport radar, telecom transmissions, electrostatic discharge (ESD), and white noise.
• Some other major product and systems as emissions sources include switching mode power supplies, arc welders, motor bushes and electrical contacts.

Effect of Ambient Noise/ Ambient EME – 

• It can affect sensitive electronic equipment Internal Voltage and Line Voltages.
• In the case of the effects of ESD on sensitive electronic systems, it can cause upsets, burn outs, and latch-ups in these units.

Power Quality degradation factors can affect the operation of equipment that is powered by a mains power source. These mains degradation factors include:

• Voltage surges, sages, dips, spikes, and high and low voltage
• Brownouts and blackouts
• Power line faults
• Electrical Fast Transitions (EFT)

Effect of Power Quality degradation Noise – 

• Power Quality distortions and transient that are present on the power main systems can affect the normal operation of the equipment to that it supplies power.
• Transits such as power surges are capable of destroying interface electronic circuits. EFTs can cause electronic circuit upset conditions.

High Powered Electromagnetic Pulses threats which are intended to disable electrical and electronic equipment.

Currently, existing HEMP devices include the following:

• High Altitude Electromagnetic Pulse (HEMP)
• High Powered Microwave (HPM)
• Intentional Electromagnetic Interference (IEMI) source

Effect of High Powered Electromagnetic Pulses – 

• High powered electromagnetic sources can totally destroy an electrical and electronic equipment’s function.
• High-Altitude Electromagnetic Pulse (HEMP) is a near-instantaneous electromagnetic energy field that is produced in the atmosphere by the power and radiation of a nuclear explosion, and that is damaging to electronic equipment over a very wide area, depending on power of the nuclear device and altitude of the burst.
• High-Power Microwave (HPM) electromagnetic energy can be produced as a near-instantaneous pulse created through special electrical equipment that transforms battery power, or powerful chemical reaction or explosion, into intense microwaves that are also very damaging to electronics, but within a much smaller area.

Railroad and Mass Transit Systems have some unique types of EMI source problems. These include:

• Train signaling systems and their associate Computer operating codes.
• Third rail shoes arcing broadband emissions
• Train control system’s emissions.

Effect of Railroad and Mass Transit Systems Noise – 

Railroad and Mass Transit Systems have one primary source of EMI and that is the transit and railroad engine’s propulsion systems, which operates with high voltages, currents, and magnetic field levels.

• They have been known to affect other facilities that contain sensitive electrical equipment that are located near the railroad or mass transit systems right away.
• These propulsion systems have had EMI associated problems with other elements of their systems.
• Train control electronics can be affected by EMI sources such as third rail and other broadband frequency arcing sources if they are not adequate designed for EMC.

Medical equipment utilized in medical facilities has numerous EMI sources. Some of the more prominent of these are listed below:

• Life support equipment such as ventilators, cardiac defibrillators, infusion pumps, etc.
• Patient telemetry and assistance equipment which includes electrocardiographs and motorized wheelchairs.
• Electrical surgical units and their associated support equipment.
• Magnetic Resonance Imagine (MRIs) system.
• X-ray units, both therapeutic and diagnostic
• Gamma Beam Electron Accelerators and Therapeutic equipment

Effect of Medical Equipment Generated Noise – 

• Medical equipment and facilities sources include patient monitoring systems
• Those are very susceptible to EMI interactions.
• The human body signals that they monitor are very weak.
• They are measured in unites of microvolts and micro-amps.
• Among other devices that are susceptible to EMI are hearing aids, wireless patient monitoring systems, magnetic resonance imaging systems, implantable cardiovascular devices, drug pumps, and portable diagnostic meters.
• As new technologies are developed and enter the marketplace at a fast pace the list will grow.