A logarithmic resistor ladder consists of a resistor string and switches designed to attenuate a signal. The state of the switches can be considered to represent a digital code proportional to the logarithm of the attenuation ratio. Logarithmic attenuation is useful when a large dynamic range is needed. Audio volume control and fading/balancing audio signals […]
Wireless
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 […]
Ka-band phased-array satellite antenna meets CS25 and CS27 needs
ThinKom Solutions, Inc. unveiled a new Ka-band phased-array satellite antenna for communications-on-the-move (COTM) applications. The new ThinSat Ka500, based on ThinKom’s proven VICTS technology, is a “turnkey” terminal that enables the user to easily and quickly connect to the network of their choice, such as the existing and new Ka-band networks being deployed using satellites in geostationary […]
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 […]
Notch filters boast built-in ESD protection function
TDK Corporation announces the release of its newly developed AVRF041A150MT242 and AVRF061D2R4ST532 notch filters with ESD protection function. Volume production of these devices will begin in March 2022. The new notch filters are compliant with the IEC61000-4-2 Level 4 immunity standard. They are well suited to ensuring EMC requirements are met in the audio circuits […]
Embedded antennas handle LTE 410/ 450 MHz bands
Antenova Ltd has revealed its latest antenna, Atta, part number SRFI079, for LTE and smart wireless deployments in the 410 MHz and 450 MHz bands. The Atta antenna is a flexible printed circuit (FPC) form and measures 101.0 x 20.0 x 0.15 mm. It is supplied with an I-PEX mating connector for direct integration to […]
From designing to operating an RF PCB: The complete guide
by Ken Ghadia, Sales Engineer, TechnoTronix Radio Frequency (RF) PCBs are very high-speed circuits operating at frequencies in the range of 100MHz and above, typically from 500MHz to 2 GHz. RF PCBs are the backbone of wireless networks, high-tech gadgets like smartphones, smart TVs, etc. Also, RF PCBs are used in automotive, medical equipment, military, […]
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 examined some of the […]
