The first part of EEWorld’s two-part “virtual roundtable” discussion on Class D audio considers technical challenges and design trade-offs for engineers using Class D audio technology. Joining us for this virtual roundtable are: Joshua LeMaire (JL), Audio Systems Architect at Analog Devices; Steve Colino (SC), Vice President Strategic Technical Sales with Efficient Power Conversion; and […]
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Sorry, but it’s “Goodbye, Caboose” – EoT devices have made you obsolete, Part 2
Part 1 of this article discussed the concept and basic implementation of the end of train (EOT) device. This part explores the EOT and its larger “ecosystem” in more detail. First, a bit of history While the first caboose replacement was a simple flashing rear-end device (FRED), first used by the Florida East Coast Railroad […]
Sorry, but it’s “Goodbye, Caboose” – EoT devices have made you obsolete, Part 1
The venerable-freight train caboose of history has been made obsolete over the past few decades by sophisticated, rugged, electronic end-of-train (EOT) devices which do much more, much better, and much cheaper. Ah, the caboose (Figure 1): it’s a railroad car which combines practicality, utility, legend, imagery, history, nostalgia, romance, dreams, myths, and so much more. […]
Hysteresis and its measurement
Hysteresis might be defined as something that happens when the physical state depends upon its history. The classic example of hysteresis in action is the residential thermostat. It has built-in hysteresis to prevent rapid cycling. It’s low cut-in and high cut-out levels are designed to prevent the heating/cooling system from rapid switching, which would quickly […]
More antennas, faster data transfer
MIMO and beamforming provide increased data rates than you can get using single, omnidirectional signals. Antennas convert between radio waves propagating through space and electric currents moving in a metal conductor. In early communication system, antennas were often quite simple, perhaps just a half-wave dipole constructed of wire. We usually just had one antenna per…
RF/Microwave bandpass filter implementations, Part 3: microstrip, coaxial, and helical filters
Part 2 looked at two types of RF/microwave filters, but there are many more, including ceramic coaxial filters and helical filters. They are discussed in this part. Microstrip filters Microstrip filters are built as a carefully defined pattern on a PC board. There is almost no limit to the filter designs which can be built […]
RF/Microwave bandpass filter implementations, Part 2: Cavity and comb filters
The well-known and extensively analyzed lumped-element bandpass filter is generally not suitable for the RF/microwave region, but there are many distributed-element, energy-based alternatives. Part 1 of this article established the context for these RF/microwave filters, which operate in the spectrum from several hundred MHz and higher, and increasingly cannot use discrete lumped-circuit elements (RLCs). Instead, […]
RF/Microwave bandpass filter implementations, Part 1: Distributed filters
The well-known and extensively analyzed lumped-element bandpass filter is generally not suitable for the RF/microwave region, but there are many distributed-element, energy-based alternatives. Just say the word “filters,” and for many engineers, the mention of this topic stirs a mix of feelings ranging from fear to relief. Why fear? Because filters as a topic in […]
The hot and cold of thermocouples
The common temperature probe contains a thermocouple consisting of two dissimilar metals welded together to form an electrical junction. A voltage that varies with temperature is generated. Slightly less accurate than resistance temperature detectors (RTDs), thermocouples cover a wide temperature range and respond quickly. Combinations of different metals create different voltage responses. All dissimilar […]
How to select components for a digital-controlled Totem-Pole PFC
By Bill Luo (Luo Zhizheng), Sr FAE, ACEINNA Transducer Systems and Jason Zhang (Zhang Liang), AE Director, Shenzhen Advantaged Power Limited There is a lot of attention being paid to advanced power systems. Energy efficiency has become a critical capability in today’s world, due to pressures from every sector of the market. To achieve substantial […]