Unwanted interference in signal processing circuitry is a common problem. It compromises signal integrity and may result in uncontrolled behaviour or even serious malfunctioning of an electrical system.
There are many sources of interference. Mostly, these are electro-magnetic fields, which may originate both from internal or external sources. On the other hand, shared impedances in current loops may also cause serious interference.
A well known example of an interferer is the power grid. The interference signal is known as hum, named after the sound, it produces in audio equipment. Other common interference sources include transformers and RF transmitters (i.e. broadcast, radar, mobile phones).
This lecture discusses the mechanisms, responsible for unwanted interference and techniques to eliminate these signals. These will be presented as a set of easily implementable, practical rules for anyone, involved in electrical circuit design and layout.
- Electro-magnetic field theory basics
- Interference by quasi-static magnetic fields
- Interference by quasi-static electrical fields
- Interference by dynamic electro-magnetic fields
- Interference by shared impedances
- Ground and supply noise
- Power grid as interferer
- Power grid as threat
- Safety measures in the lab
- Interference in device interconnections
- Interference in oscilloscope measurements
Bachelor or Master degree Electrical engineering and
preferably some knowlegde about Spice simulation
The training has been given by J. Olde Dubbelink, Engineer of Bruco integrated Circuits