Analyzing Pulse-Width Modulation Signals

Figure 1: Persistence display provides
a quick-and-dirty view of a PWM signal

Pulse-width modulation (PWM), a favorite technique for achieving analog ends through digital means, finds application in all kinds of end systems. Motor control might be the number-one application, but PWM turns up in telecommunications, audio systems and amplifiers, and any number of other uses. Armed with a capable oscilloscope, one can thoroughly analyze and understand the behavior of PWM circuits.

Back to Basics: Jitter

Figure 1: Jitter is short-term variation
of a signal with respect to its
ideal position in time

Anyone working in applications that involve digital data, clocks, and serial data in general will eventually bump up against issues concerning jitter. Jitter is a subject of keen interest to every strata of the electronics industry. Chip makers, board integrators, system integrators, you name it: Everybody wants, and needs, to come to terms with jitter. It impacts reliability, manufacturability, and cost at all levels. And, of course, it's of keen interest to purveyors of test instruments, including us here at Teledyne LeCroy. In this first post of a projected series on jitter, we'll look at some of the tools built into modern digital oscilloscopes for jitter measurement and analysis.