Impedance matching between RF stages has always been a priority to ensure maximum transfer of RF power along with minimal RF-power reflections. Although most RF systems are designed for nominal 50-ohm input and output impedance (and 75-ohm for cable TV), the reality is that many components do not present that preferred 50-ohm impedance due to […]
Gyroscopes, Part 2: Optical and MEMS implementations
Part 1 of this FAQ examined the basics of IMUs based on spinning-rotor gyroscopes to establish and maintain a fixed attitude via a gimbaled platform, along with orthogonal accelerometers to sense motion along each axis. Part 2 looks at optical and MEMS-based gyros which have largely replaced the spinning-rotor core function except in the most-demanding […]
Gyroscopes, Part 1: Context and mechanical designs
We now take as a “given” the ability to know where we are and where we are going, and do both with accuracy and precision (and with simplicity and low cost, but these are relatively recent developments. Prior to the availability of inertial measurement systems based on gyroscopes and accelerometers, navigation was a time-consuming, difficult, […]
Network topologies, Part 2: Advanced interconnections
Part 1 of this FAQ started out with conceptually simple, widely used, and indispensable point-to-point and bus topologies often implemented using RS-232, RS-485, and Ethernet standards. These basic topologies are suitable in many situations but are inadequate as the number of nodes increases, or as other performance issues become priorities. Part 2 looks at other […]
Network topologies, Part 1: Basic interconnections
A network can be a simple and direct as a connection between just two points (nodes), or it can incorporate tens, hundreds, thousands and even more nodes. How these nodes are connected, how the network functions under ideal and stressed situations and traffic levels, and the key attributes of each network configuration is largely defined […]
Microwave/Millimeter Wave interconnects, Part 2: Connectors and cable assemblies
Part 1 of this FAQ look at the coaxial cables used in microwave/millimeter wave interconnects and cable assemblies. But a cable alone is only half a solution; the cable must be terminated with connectors. Often, the completed cable/interconnect assembly is also called a cable, but this is generally not an ambiguous situation (but it may […]
Microwave/Millimeter Wave interconnects, Part 1: Coaxial cables
Cables, connectors, and interconnects (cable assemblies) are essential yet often underappreciated parts of a system design. Even though the popular meme is “everything is going wireless” thus eliminating the need for cable assemblies, the reality is that these assemblies are critical both within circuits at either end of a wireless link or as the only […]
RF power measurement, Part 2: What and how
Part 1 of this FAQ introduced some of the basic issues related to the measurement of RF power, which is a primary parameter in most RF designs. Part 2 continues the discussion, looking at RF waveforms and sensors. Q: The term “power” is fairly broad; what are the specifics? A: There are actually several basic […]
RF power measurement, Part 1: Why and where
When the subject is RF design, the word “power” dominates much of the discussion. This FAQ looks at some perspectives related to the measurement of this vital RF parameter. Not only is power and measuring it among the most important RF design considerations, but it is also generally difficult to assess accurately, and it is […]
The RF power amplifier, part 2: considerations
Part 1 of this FAQ looked at the basic role and function of the RF power amplifier (PA). This part looks at some of the factors to consider when looking at possible PA devices. It is not a detailed run-through of the many parameters which characterize PAs, including many which are unique to the PA […]