Advanced waveform generation techniques for ATE

Abstract

Comprehensive waveform generation is an important functional component of automated test equipment (ATE). Waveform generators synthesize signal stimuli to be applied to a device under test (DUT). As military and commercial electronics become increasingly complex, more sophisticated signal stimuli are required. ATE requires signal stimuli varying from advanced communication signals to the playback of captured real-world analog signals. Waveform generators can synthesize signals that can be broadly categorized into four types: standard functions, advanced functions, arbitrary waveforms, and waveform sequences. Standard functions include the simple sine, square, triangle, pulse, and ramp waveforms. Advanced functions include complex signals such as multi-tone, AM, FM, sinc pulse, haversine, half-cycle sine, Gaussian pulse, Lorentz pulse, noise and others. Arbitrary waveforms involve the point-by-point user-defined waveform synthesis. Waveform sequences provide a mechanism to piece together standard or arbitrary waveforms in stages to create a user-defined compound waveform. Example applications for each of these four waveform categories are described in this paper. Modern waveform generators are extremely powerful, but can also add significant complexity for the user. The arbitrary waveform generator, an instrument found in most ATE systems, is a very powerful signal synthesis tool. Unfortunately, many users take advantage of only a small fraction of the powerful features available to them in an arbitrary waveform generator. Also, selecting the right arbitrary waveform generator can be daunting when comparing specifications such as DAC resolution, clock rates and topology, memory depth, sequencing, sweeping, triggering and synchronization. This paper describes the technical differences between various signal generation techniques, presents the signal fidelity impact of clock topology, discusses dynamic range limitations due to noise, accuracy and resolution, and provides typical applications to illustrate signal generation usage. Ultimately, this information should help the user avoid common pitfalls in applying waveform generators within ATE.