Finding the right analog filter to build a sensor circuit doesn’t have to be complicated. Understandably, the plethora of filter options can be overwhelming. Also, selecting a less-than-ideal filter may result in compromises, potentially increasing system cost, or affecting performance. To help simplify filter selection, this series of blogs explore key considerations when assessing your […]
FAQ
An overview of filters and their parameters, Part 4: Time and phase issues
Understanding how filters are characterized is the first step in choosing an appropriate topology with suitable specifications. Thus far, we have focused on filters primarily in terms of their frequency response. However, it is equally legitimate to look at their time-domain and phase-related performance, and in many cases, just as or even more important. Q: […]
An overview of filters and their parameters, Part 3: Key parameters
Understanding how filters are characterized is the first step in choosing an appropriate topology with suitable specifications. This part looks at the basics of filter characterization and parameters. Q: What is an example of a very basic filter? A: The most common analog filter is the single-stage low-pass RC filter (Figure 1). It is often […]
An overview of filters and their parameters, Part 2: Basic Concepts
Understanding how filters are characterized is the first step in choosing an appropriate topology with suitable specifications. Filters are both a simple and also complicated and often confusing topic. This part clarifies some of the issues. Q: Why are so many discussions about filters so confusing? A: There are many reasons, but one is that […]
An overview of filters and their parameters, Part 1: Context
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 […]
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 […]
