Frequency bands within the electromagnetic spectrum have multiple, sometimes confusing, overlapping designations. Electronics engineers must deal with the electromagnetic spectrum as a routine part of their wired and wireless projects. This spectrum of interest ranges from relatively low frequencies in the kilohertz (kHz) range (or perhaps lower) into the tens and even hundreds of gigahertz […]
Wireless
The why, where, and how of automatic gain control, Part 1
There are many ways to implement the automatic gain control function, which is critical to the proper performance of many wireless and other links. The automatic gain control function has been embedded in radio links since the earliest days of wireless technology, but the need for AGC is not limited solely to that application. Along […]
Antennas for cellular, Wi-Fi, Tetra, UHF and GNSS optimized for tram, light-rail uses
Dedicated antennas optimized for light rail vehicles have been launched by HUBER+SUHNER, further expanding its offering to the transport sector. As all transportation market segments look to cope with rising bandwidth demand, rail, light rail, and road vehicles all have different requirements. The SENCITY Tram rooftop antenna range has been developed to provide an all-in-one […]
What materials can be used to make miniature antennas?
Many antennas are mechanically simple and electrically complex at the same time. Mechanically an antenna usually has only one or two components, a dielectric layer (which can be the entire antenna) and a conductive layer. This FAQ begins with a brief review of dielectric materials and their importance to antenna performance. It then explores developments […]
Wideband, log periodic, directional antennas handle bandwidths of 600 to 6,000 MHz
Fairview Microwave has expanded its line of wideband, log periodic antennas that operate from 600 to 6,000 MHz for point-to-point wireless communications. Fairview’s new, outdoor-rated, directional antennas function as boosters where the existing cellular signal is weak and needs to reach longer distances. This makes them ideal for strengthening 5G, 4G, LTE, CMDA, LoRA, IoT, and Wi-Fi signals. […]
What’s the difference between equalizers?
Equalizers are used to alter the performance of signal chains. In some cases, that means linearizing signal chain performance. In other cases, equalizers are used to introduce nonlinearities. As a result, equalizer designs vary widely from simple passive circuits to complex multi-stage designs and active circuits. This FAQ reviews equalizer basics, looks at equalizers for […]
What’s a logarithmic resistor ladder good for?
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 […]
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 […]
