Balanced Line Technology

Balanced inputs and outputs have been used for many years in professional audio, but profound misconceptions about their operation and effectiveness still survive. Conventional wisdom about them is sometimes wrong. Balanced Line Technology web page gives you a good look at the balanced line technology in audio applications. The balanced line technology is also applicable

EMF measurements

An electromagnetic field (also EMF or EM field) is a physical field produced by moving electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction. It is one of the four fundamental forces of nature. EMF measurement

Audio and video signal susceptibility classes

My article Signal reference grids in the data center shows that different types of data communication interfaces are classified into susceptibility classes: Data communication interface classification Susceptibility class: Low immunity Interfaces in class: Parallel ports, RS-232 ports, Proprietary back-plane, Video cables Characteristics: Copper cabling with ground referenced signals. Any shift in ground voltage between the

Mains power isolation for ground loop solving

It is sometimes suggested that a mains power isolation transformer might be used to solve the ground loop problem. It is true, that many times a mains isolation transformer does help, but not always. A system with properly used isolation transformer is still safe, it can be even safer than system without isolation transformer. Remember

Grounding and EMI

One of the most common direct coupled noise sources is when the ground which is being used for reference or return is not referenced to earth as expected. This is especially prevalent in sensitive high-gain circuits. Grounding and Shielding Existing Equipment – How to effectively minimize EMI issues when best practices are not available is

How to protect RS-232 serial connections

How to protect RS-232 serial connections article pointed me to a recent white paper from APC-Schneider Electric that explains specific power protection issues related to RS-232 cabling. The Protection of RS-232 Serial Connections document contends that the RS-232 port often represents the “Achilles heel” of computer installations which are otherwise well protected by UPS systems

PCB grounding

Board-level designers often have concerns about the proper way to handle grounding for integrated circuits (ICs) which have separate analog and digital grounds. Should the two be completely separate and never touch? Should they connect at a single point with cuts in the ground plane to enforce this single point or “Mecca” ground? How can