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 […]
filters
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 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 […]
What are reflectionless filters? Part 1: Context
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 inherent, inescapable, necessary component in electrical and electronic circuits. Modern systems would be impractical and likely impossible without filters, whether at low frequencies down to […]
Notch filters boast built-in ESD protection function
TDK Corporation announces the release of its newly developed AVRF041A150MT242 and AVRF061D2R4ST532 notch filters with ESD protection function. Volume production of these devices will begin in March 2022. The new notch filters are compliant with the IEC61000-4-2 Level 4 immunity standard. They are well suited to ensuring EMC requirements are met in the audio circuits […]
The practical magical first-order analog filter: Part 1
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 […]
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 […]
