The digital phosphor oscilloscope (DPO) provides oscilloscope architecture a whole new approach. This architecture allows a DPO to deliver innovative display and acquisition capabilities to accurately reconstruct signals.
Unlike a digital storage oscilloscope (DSO), which employs a serial-processing architecture to capture, analyze and display signals, a DPO uses a parallel-processing architecture to capture, display and analyze signals. The architecture of DPO also dedicates ASIC hardware to acquire waveform images. This enables the DPO to deliver high waveform capture rate which results to optimized signal visualization and increases the chances of viewing transient events occurring in digital systems, such as glitches, transition pulses and runt pulses, as well as allows additional analysis capability.
The input to a DPO is much like an analog oscilloscope, which uses a vertical amplifier, while its second stage is the same with that of a DSO. It is, however, at this point that DPO’s architecture differs from that of its predecessors.
Whether the oscilloscope is a DSO, DPO, or analog, there is always a time delay during the processing of the recently acquired data, resetting of the system, and waiting for the next trigger event. During this period, the oscilloscope does not view any signal activity. As the time delay increases, the chances of seeing low- or infrequent repetition event also decreases.
It has to be emphasized that the probability of capture can not be determined solely by looking at the display update rate. Relying on the update rate alone may lead one to erroneously believe that the oscilloscope captured all significant information about the waveform, when it actually did not.
While the DSO captures waveforms serially — which can form a bottleneck — the DPO eliminates data processing bottleneck by converting digitized waveform data into a digital phosphor database and copying it directly to the display memory. This process allows the DPO to conveniently capture intermittent events, signal details and characteristics in real-time. So as not to affect the acquisition speed of the DPO, its microprocessor works in parallel with an integrated acquisition system for measurement automation, display management and instrument control.
Unlike an analog oscilloscope’s dependence on chemical phosphor, a digital phosphor oscilloscope utilizes an electronic digital phosphor that is an updated database. Every captured waveform is mapped into the cells, which represents a screen location of the digital phosphor database. Each cell touched by the waveform is added with intensity information, which builds up in cells often passed by waveforms.
Feeding the digital phosphor database to the display of the oscilloscope reveals intensified waveform areas in proportion with the number of occurrence of a particular signal at each point. Unlike analog oscilloscope, a DPO displays varying frequency-of-occurrence information in contrasting colors. It also breaks the barrier between the technologies of analog and digital oscilloscope — which are ideal for viewing low and high frequencies, transients, repetitive waveforms, and signal variations in real-time.
Ideal for those who want the best troubleshooting tool, a DPO is exemplary for communication mask testing, advanced analysis, repetitive digital design, digital debug of intermittent signals and timing applications.