Part 1 looked at the eye diagram, a simple yet powerful visual tool which reveals many specifics about the quality of a recovered bit stream. Part 2 looks at the constellation diagram, another powerful visual tool which is used to show the signal space of complex encoding schemes and relationship among the symbols. Q: Why […]
Industry Experts
Eye and Constellation Diagrams, Pt 1
Digital signals representing data symbols may be presumed to be clean, consistent representations of ones and zeroes when they are launched onto their communications medium, whether it is a wired, wireless RF, or optical fiber link. However, due to bandwidth limitations of the medium, external and internal noise, crosstalk, multipath, reflections, and many other unavoidable […]
Impedance matching and the Smith Chart, Part 2
Part 1 looked at impedance matching and the need for a complex conjugate impedance at the load, compared to the source impedance. Once the need for an impedance-matching network is determined – and it is very likely needed – the next challenge is defining and creating this network. It may seem that doing a few […]
Using the Smith Chart for impedance matching, Part 1
In circuit designs spanning low-frequency audio through high-frequency RF, there’s considerable discussion about impedance matching between components or subcircuits, with various tools such as the Smith chart with is used to facilitate the matching. Q: What is impedance matching? A: Impedance matching means that a signal source sees a load impedance which is the complex […]
Why use a nonlinear amp?
Users normally place a great deal of value in the high linearity of an amplifier and its corresponding low distortion. Audio amplifiers, for example, are quoted with many linearity specifications, such as total harmonic distortion (THD) or 1%, 0.1% or even less. Even the outputs of amplifiers with internal topologies which are inherently nonlinear, such […]
Optocoupler selection and usage for isolating a PWM
An optocoupler (or optoisolator) is a device that galvanically separates circuits and is not only great at isolation but allows you to interface to circuits with different ground planes or that operate at different voltage levels. Optocouplers are “fail safe” in that if subjected to voltages higher than the maximum rating, they are known to […]
What is a clock and what are its critical parameters (Part 2)?
The performance of a clock function, which includes the crystal and associated circuitry, is defined by parameters which are measured over both the short term and long term. It is also characterized by change in specifications due to temperature variations, aging, and mechanical considerations such as vibration and shock. How is clock performance defined? Both […]
Top analog threads on EDAboard.com – March
(editor’s note: Intrigued by the problem? Have a question or another solution? Then click the “Read more” link and follow the conversation on EDAboard.com or log in to EDAboard and participate in the analog IC forum threads.) Battery voltage warning – I have 2 circuits. The idea is to show a warning when the battery drops […]
Khurrum Dhanji, CEO of Imagineering Authors ‘The Printed Circuit Buyer’s Guide to… AS9100 Certification’
Imagineering, Inc. announced recently the release of their valuable new resource: The Printed Circuit Buyer’s Guide to… AS9100 Certification. Authored by Imagineering CEO Khurrum Dhanji, “The Printed Circuit Buyer’s Guide to… AS9100 Certification” is the first book in an ongoing series of micro eBooks specifically dedicated to the education of the PCB design, fabrication and assembly industry. The […]
What is a clock and what are its critical parameters (Part 1)?
The “clock” function is a standard part of nearly every electronic system, with very few exceptions. Behind this simple-sounding, commonplace word, there is an array of complexity and subtlety in definition, performance, and design. Clocks are both vital and ubiquitous, so it is worth understanding the different functions they fulfill, they ways they can be […]