Digital phosphor oscilloscope combines analog, digital strengths

Most engineers use digital storage oscilloscopes (DSOs) for simultaneous, multi-channel operation, measurement automation, and waveform storage. Many also keep their old analog real-time (ART) oscilloscopes for intensity-graded displays, varying brightness, and fast waveform capture rates that can indicate frequency of different signal sections.

Most engineers use digital storage oscilloscopes (DSOs) for simultaneous, multi-channel operation, measurement automation, and waveform storage. Many also keep their old analog real-time (ART) oscilloscopes for intensity-graded displays, varying brightness, and fast waveform capture rates that can indicate frequency of different signal sections. In short, neither oscilloscope can meet all signal characterization needs. Until now.

To give engineers the benefits of both architectures, Tektronix (Beaverton, Ore.) released Jan. 4 its second family of digital phosphor oscilloscopes (DPOs) within the past six months. The six-model TDS3000 family starts at $2,995 and includes up to 500 MHz bandwidth, four-channel operation, and a five gigasample per second (Gs/sec) sample rate.

Using one DPO, engineers can capture virtually all useful waveform information in three dimensions: amplitude, time, and intensity expressed as amplitude distribution over time. This combines an ART’s intensity-graded display and responsiveness with a DSO’s storage, measurement, and triggering capabilities.

How a DPO works

TDS3000 functions by digitally emulating the chemical phosphorescence process that creates intensity grading in an analog oscilloscope’s CRT. In a DPO, a waveform is first digitized similar to a standard DSO. The DPO then rasterizes the waveform in a three-dimensional database called digital phosphor, and the data is periodically sent to the display system. At the same time and in parallel, its microprocessor performs automatic measurements and math functions.

Because its parallel processing integrates acquisition and display, the DPO can perform both jobs continuously. It’s less burdened by display management tasks than a DSO in which every bit of displayed data must go through its processor while it’s also trying to complete other calculations. As a result, the DPO can support a much better waveform capture rate that provides a real-time display of signal activity.

TDS3000’s improved waveform capture and display means field engineers can, for example, quickly compliance test against industry standards using stored waveforms. Ideal images also can be captured in one location and quickly distributed to multiple manufacturing sites, allowing technicians to standardize reference tests.

In addition, the DPO’s ability to simultaneously delineate between four colored signals provides added detail and insight into multisignal applications. Its logic, pulse triggering, and Fast Fourier Transform can simplify design verification. Likewise, during debugging processes, TDS3000’s intensity-graded display also indicates relative frequency of signal anomalies.

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