Originally derided as scientifically erroneous, the Doppler effect is now a vital tool in all aspects of technology, ranging from microscopic to galactic. Doppler, back in the day – and now The explanation of the Doppler effect is almost intuitive to us, with our understanding of wave phenomena along with available frequency sources and measurement […]
The Doppler effect: From highly ridiculed to absolutely indispensable, Part 1
Originally derided as scientifically erroneous, the Doppler effect is now a vital tool in all aspects of technology, ranging from microscopic to galactic. Engineers are familiar with many “effects” ranging from widely used ones such as the piezoelectric effect to somewhat lesser-known ones such as the RF skin effect and even less-familiar ones such as […]
PIGAs can indeed fly – and are still the best, Part 3: History and future
The PIGA is the oldest accelerometer and widely used in rocketry and guidance, and still the best – but MEMS-based devices are getting closer. The previous parts looked at the principle and operation of the PIGA. This part looks briefly at its history and refinement and the MEMS-based versions of the PIGA being developed and […]
PIGAs can indeed fly – and are still the best, Part 2: Operation
The PIGA is the oldest accelerometer and widely used in rocketry and guidance, and still the best – but MEMS-based devices are getting closer At the core of each single-axis PIGA is a gyroscope. The performance of this gyro – which is unrelated to the orientation gyros – plays a large role in determining the […]
PIGAs can indeed fly – and are still the best, Part 1: Frame of reference
The PIGA is the oldest accelerometer, is widely used in rocketry and guidance, and is still the best – but MEMS-based devices are getting closer. When you see an inexpensive drone, a more sophisticated one, an unmanned aircraft, a standard piloted aircraft, guided or intercontinental ballistic missile ICBM), an underwater drone or submarine, or a […]
System integration and debug: Go incremental or go “all up”?
There are two somewhat conflicting approaches for integrating and debugging a system, and you never know which would have been better – until the project is done. Bringing up and debugging a complex system with multiple functions and ICs is a challenge, no news there. You’ve got to make sure all the components play with […]
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 stop-band 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 […]
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 […]