This essential measurement accessory for microwaves has morphed from waveguides down to tiny surface-mount components. Part 1 looks at the need for and the basic principles of directional couplers. This part explores some of the construction techniques and implementations. The basic arrangement of a single directional coupler is shown in Figure 1. There are two […]
FAQ on RF directional couplers: part 1
This essential measurement accessory for microwaves has morphed from waveguides down to tiny surface-mount components. Engineers who work with circuits typically use a multimeter as their primary test and measurement tool to check voltages and currents. They may also need to assess power with a separate instrument, but this is often secondary. However, voltage and […]
FAQ on spread spectrum for switching-supply EMI management Part 2: details
Spread spectrum minimizes the EMI impact of switching power supplies and helps meet regulatory mandates. This discussion of spread-spectrum topologies for switching regulators and converters continues with a look at some modulation and component details. Q: What are some of the issues associated with the frequency modulation spread spectrum (FMSS)? A: Keep in mind that […]
FAQ on spread spectrum for switching-supply EMI management Part 1: overview
Spread spectrum minimizes the EMI impact of switching power supplies and helps meet regulatory mandates. Noise is a concern and consideration for many circuit designs, and there are many types of noise. There is external noise, such as from nearby motors or RF interference sources, and internal noise, which is generated by various sources of […]
Does 32 kHz or 3.58 MHz mean anything to you? part 2
These two frequencies played major roles in electronics; one is still viable, while the other is entirely obsolete. Find Part 1 here. Color TV was developed in the 1950s and 1960s, largely by Radio Corporation of America (RCA) (see Related EE Word content), as a compatible upgrade to black and white (monochrome) TV. Adding color […]
Does 32 kHz or 3.58 MHz mean anything to you? part 1
These two frequencies played major roles in electronics; one is still very viable, while the other is completely obsolete. Engineers are surrounded by countless standard frequencies, many of which are defined by an industry standard. Some are so well-known and commonplace that they need no clarification other than the frequency number itself; others were “celebrities” […]
What is “twin-lead” transmission line — and what happened to it?
Twin-lead line was once the dominant transmission medium for consumer products such as TVs; it has been largely, but not entirely, made obsolete by coaxial cable. When engineers need to make a wired RF connection to create a transmission path or line between two subsystems such as a transmitter/receiver and its antenna, their first and […]
Passive RFID finds unanticipated mass-market applications: part 2
Passive RFID tags have been widely adopted, and some applications show creative adaptation to unmet needs. While many uses for passive RFID tags were predicted and expected, innovators implemented some that were not obvious. This part will look at two of those applications. Clothing-store “mass” checkout One obvious application predicted for passive RFID labels was […]
Passive RFID finds unanticipated mass-market applications: part 1
Passive RFID tags have been widely adopted, and some applications show creative adaptation to unmet needs. It’s interesting to see how advances in technology often are adapted to applications that were not highlighted in their original “use case” scenarios and how clever people adapt or leverage new technologies in unscripted ways. A good example of […]
FAQ on Luneburg lens to increase radar signature: Part 3
The Luneburg lens is an extremely efficient reflector of radar energy based on advanced principles and fabrication techniques. The theoretical Luneburg lens requires a smooth, continuous gradient of the refractive index from the center to the outside. In practice, this is generally not a viable type of construction (but that is changing). Q: What is […]
