Understanding how filters are characterized is the first step in choosing an appropriate topology with suitable specifications. Mention “filters” to electrical engineers of the older persuasion, and you’ll likely see a look of nostalgia mixed with fear. Why so? Because “back in the day” a course on filter theory was mandatory for nearly all EE […]
FAQ
A look at intrinsic broadband noise spectral density
You can think of noise as an unwanted signal. This signal creates an error by combining with the desired signal in your circuit. Exterior sources can couple into your circuits, such as your 50 or 60 Hz DC mains signal or your cell phone. The starting point in your circuit’s noise evaluation is to reach […]
Squash 1/f noise with zero-drift amplifiers
There is a device that squashes all the 1/f voltage and current noise calculations with a chopper amplifier algorithm that corrects offset and drift characteristics. These amplifiers are zero-drift, auto-zero, or choppers that all achieve nanovolt-level offsets and extremely low offset drifts due to time and temperature. But back to our noise discussion, these devices […]
3D printing for 5G systems
MIMO antennas, waveguides, traveling wave tubes, and RF substrates are fabricated using various 3D printing technologies. For example, 3D printing has been used to produce highly dense and integrated waveguide signal interconnects modules in a single monolithic unit. By printing the waveguide modules in one component, the part count was significantly reduced from tens or […]
Free-space optical links, Part 3: Standard units
Free-space optical links provide a reliable, cost-effective, and quick way to link two fixed communication nodes located a few kilometers apart. The previous part of this article looked at real-world issues that make a practical FSO link a design challenge. This part looks at a family of commercially available FSO systems. Q: Can you build […]
Free-space optical links, Part 2: Technical issues
Free-space optical links provide a reliable, cost-effective, and quick way to link two fixed communication nodes located a few kilometers apart. The first part of this article established the basic operating principles and rationale for free-space optical links. This part looks at some practical issues associated with their implementation. Q: How do you aim the […]
Free-space optical links, Part 1: Principles
Free-space optical links provide a reliable, cost-effective, and quick way to link two fixed communication nodes located a few kilometers apart. When engineers think of “optical data links” or “optical communications” they almost invariably think of light (visible or not) in an optical fiber carrying data at high rates for tens or even thousands of […]
What are the applications of 3D and 4D printed electronics?
3D printing is the fabrication of a three-dimensional object under computer control, with one or more materials being added layer by layer. 3D printing, or additive manufacturing, is used across various electronics applications, including circuit boards, energy storage devices, actuators, and sensors. It can be implemented using a variety of technologies, including selective laser sintering […]
Including the often overlooked 1/f current noise
It is tempting to center your attention only on voltage noise when using operational amplifiers in the circuit. This impulse is attractive because the current noise is always well below the voltage noise specifications. But be careful. Don’t jump to conclusions without looking at all the elements in this noise challenge. This blog explores the […]
What is passive intermodulation?
Passive intermodulation (PIM) is a pernicious and destructive phenomenon for cellular network operators. PIM shows up as a set of unwanted signals created by mixing two or more strong RF signals. Mixing generally produces the sum and difference frequencies of the two transmit signals F1 and F2. These signals are F1 + F2 and F1 […]
