February 2013

The extensive use of power electronics on vessels and offshore installations, especially on electric propulsion ships, has had a substantial impact on the power quality of the power distribution system. This article discusses the effects of current harmonic distortion created by commercial uninterruptible power supplies (UPS) being deployed in Naval shipboard applications.

Shielding to control EMI is a staple in modern electronics, playing a major role in military applications. Internal design practices can do much to control EMI in commercial and industrial electronics, but there is a limit to how much you can do. The EMI demands in military electronics are such that good internal design practices are inadequate - shielding is usually needed.

Nowadays, semiconductor technology requires that integrated circuits be interconnected at very high-speed data rates. Taking time domain measurements on the digital links can offer challenges for electronic engineers, one of which is to decide which is the better measurement instrument to use in the given signal integrity environment. The time domain reflectometer (TDR) and vector network analyzer (VNA) are the staple instruments to consider, each one having its pros and cons. Here we compare the responses of the two instruments when used for taking time domain measurements of typical signal integrity devices under test (DUTs): a stripline and a through hole on a FR-4 board.