The much-awaited next generation of PCIe makes it important to understand bit error-rate measurements. Hiroshi Goto, Anritsu Co. PCI Express (PCIe) 6.0 is being developed to meet the high-speed data transmission needs of emerging applications, particularly data centers supporting 5G. It features a doubling of data rates and other enhanced performance specs but at a […]

# FAQ

## Whatever happened to parallel interfaces?

Back in the early days of desktop personal computers, parallel interfaces were the norm rather than the exception. The parallel moniker refers to the way the data is sent; parallel ports send multiple bits of data simultaneously, as opposed to serial communication where bits pass one-at-a-time typically over a single connection. The rationale for parallel […]

## The many measurements of power quality

There’s a confusing variety of ways to quantify power consumption. Make sure you understand what your favorite power metric means. To most engineers, the concept of power quality pertains to characteristics of the ac line feeding grid energy to equipment in a facility. But variations of the “power quality” term now can refer not just […]

## Review: Working with the Tektronix MDO3104

The model number on the Tektronix MDO3104 oscilloscope denotes that it is a 3000-Series Mixed-Domain Oscilloscope. The mixed domain moniker means it is capable of displaying a waveform simultaneously in the time domain and in the frequency domain. The time domain is more familiar, the way we envision a sine wave when amplitude is plotted […]

## Is there such a thing as a catenary antenna?

A conic section is formed by the intersection of a plane that cuts though a cone, usually with the circle at the top and the hyperbola at the bottom. Between them lie the ellipse and the parabola. The parabola has distinctive properties when rotated in space to make a concave surface. The parabola can be […]

## The ups and downs of bad DACs

A digital-to-analog converter (DAC) is more prone than an analog/digital converter to signal degradation. DACs are complex devices requiring precisely matched components. For this reason, with notable exceptions, DACs are implemented as mixed-signal ICs based on MOSFET technology. Discrete component DACs are found in radar systems and high-speed test equipment including digital sampling oscilloscopes. Digital […]

## The up side of under sampling

A digital signal can be derived from the original time-varying, continuous analog signal by creating a sampled sequence of quantized values. It is intuitively evident that the fidelity and resolution of this quantized signal is based upon the number of samples taken per unit of time. Harry Nyquist published an early version, later further formalized […]

## Measuring and using static electricity

Many moons ago, a future member of our editorial staff was playing with his very first multimeter. He was a farm kid. One of his first experiments was to put the negative lead of the meter on a ground rod and the positive lead on one of the metal bands used to reinforce the interlocking […]

## What is “orthogonal”? (Part 4): eye diagrams

The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. Just as both the time domain and frequency domain are two legitimate ways of looking at a signal from different perspectives linked by the Fourier transform, the constellation diagram has a time-domain complement called the eye diagram or eye […]

## What is “orthogonal”? (Part 3): signal constellations

The phrase and concept “orthogonal” is widely used in engineering, but it is also often misunderstood. We can look at orthogonal signals in multiple ways: in the time domain, the frequency domain, as a constellation – a presentation which is widely used in the broad discipline referred to as signal processing, and as an eye […]