The classic wooden breadboard is obsolete, but its name continues to refer to a vital engineering tool that has changed to meet today’s component and design realities. As leaded components such as discrete transistors and low-pin-count ICs in DIP packages came into use in the late 1960s and 1970s, breadboarding technology evolved as well. Among […]
Breadboards evolve to meet 21st-century design needs, Part 1: The “Ancient” Past
The classic wooden breadboard is obsolete, but its name continues to refer to a vital engineering tool that has changed to meet today’s component and design realities. Breadboards have a special place and multiple meanings in the engineering lexicon. So, what is a breadboard? It can be a crude try-out version of a subcircuit to […]
What are reflectionless filters, Part 4: implementations
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stopband and passband which greatly improves performance of the RF signal chain. Filters are an area of intense interest, analysis, simulation, and often physical fabrication along with tests and academic papers. Yet, for hands-on design engineers, it’s important to be […]
What are reflectionless filters, Part 3: basic principles
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stopband and passband, which greatly improves performance of the RF signal chain. Beginning in 2011, Dr. Matthew A. Morgan of the National Radio Astronomy Observatory (NRAO) in Charlottesville, West Virginia, working with Tod A. Boyd and later with Wavley M. […]
What are reflectionless filters? Part 2: The need
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stop band and pass band which greatly improves performance of the RF signal chain. The higher frequency world of hundreds of megahertz and into gigahertz is very different than the low-frequency world. It is a world where design tools such […]
What are reflectionless filters? Part 1: context
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stopband and passband which greatly improves performance of the RF signal chain. Filters are an inherent, inescapable, necessary component in electrical and electronic circuits. Modern systems would be impractical and likely impossible without filters, whether at low frequencies down to […]
Tolerance analysis distinguishes prototypes from production units
It’s not enough to model and simulate circuit behavior – you also have to investigate the effects of component variations from their nominal values due to unavoidable tolerances. There’s a semi-serious quip that scientists can build one of anything – but just one; it takes engineers and production experts to build it again and again […]
Optical links for spacecraft, Part 2: Projects and progress
Using laser-sourced light beams rather than wireless RF to link spacecraft with Earth offers the possibility of a significant increase in data rates. Still, there are significant technical challenges to the concept. The previous part of the article established the need for higher-speed data links to spacecraft and their missions and looked at some of […]
Optical links for spacecraft, Part 1: The throughput limitation
Using laser-sourced light beams rather than wireless RF to link spacecraft with Earth offers the possibility of a significant increase in data rates. Still, there are significant technical challenges to the concept. Scientists, engineers, and researchers communicating with spacecraft have a problem: there’s so much data coming from these spacecraft – and to send to […]
The PC-board atomic clock, Part 3: The CSAC cesium physics cell
Atomic clocks have shrunk from room-sized assemblies down to PC-board mountable modules, admittedly with lower performance than their big siblings but still far better than crystal-based timing alternatives. Every engineer knows that developing a viable design and product is not just a matter of theorizing a design, identifying the constituent components, or building a single […]