Using Oscilloscope Mask Testing to Capture Elusive Events

Blog Post created by BoonCampbell Employee on May 23, 2017

 Oscilloscopes are used to measure and evaluate a variety of signals and sources. They also play a major role in both design and manufacturing, providing a visual display of voltage over time. Many times oscilloscope users need more than a visual representation and want to validate the quality and stability of electronic components and systems. The Keysight Technologies mask test option, DSOX6MASK, for InfiniiVision Series oscilloscopes can save you time and provide pass/fail statistics in seconds. The mask test option offers a fast and easy way to test your signals to specified standards, as well as the ability to uncover unexpected signal anomalies and glitches. Mask testing on many industry oscilloscopes is based on software-intensive processing technology, which tends to be slow. Keysight’s mask test option is based on hardware-accelerated technology performing up to 270,000 real-time waveform pass/fail tests per second. This makes your testing throughout orders of magnitude faster. This Keysight InfiniiVision ground breaking Mask Technology is supported by their industry leading highest sampling rate at 1,000,000 waveforms per second allowing for improved display quality to catch subtle waveform details such as noise and jitter.


Mask Testing

Figure 1 shows a pulse-shaped mask using an input signal standard. You can easily specify horizontal and vertical tolerance bands in either divisions or absolute volts and seconds. You can set up the mask test to run continuously in order to accumulate valid pass/fail statistics. In this example, an infrequent glitch was quickly detected. In just six seconds, the mask test statistics show that the scope performed the pass/fail mask test on more than 1,000,000 waveforms and detected just two errors for a computed error rate of 0.0002%. In addition, you can see that this particular signal has a sigma quality relative to the mask tolerance of approximately 6.1 σ.

Mask Testing

Figure 1 - Mask testing uncovers an infrequent signal anomaly


Importing an industry-standard mask -

Figure 2 shows testing results of an industry standard imported eye-diagram mask. This particular polygon-shape mask is based on a published standard and was created using a simple text editor.

 Mask Testing

Figure 2 - Testing an eye-diagram with an imported industry standard mask.


You can also set up masks around areas of the signal that should be off-limits. That way you do not need a perfect signal; just an understanding of how a signal looks when it functions correctly. Mask testing provides more reliability than testing individual attributes because the entire signal can be evaluated against a correct signal to find glitches and/or errors. As a result, mask testing saves time and money in design and manufacturing and ensures customers receive higher-quality products sooner.


Keysight Mask Test Functions include -

  • Automatic mask creation using input standard
  • Easily download multi-region masks and setups based on industry standards
  • Detailed pass/fail statistics
  • Test to high-quality standards based on sigma
  • Multiple user-selectable test criteria


When setting up your specific mask test criteria, you can choose from multiple options including:

  • Run forever (with accumulated pass/fail statistics)
  • Run until a specified number of tests
  • Run until a specified time duration
  • Run until a maximum ideal sigma standard
  • Stop-on-failure
  • Save-on-failure
  • Print-on-failure
  • Trigger out-on-failure


Low Noise –

Lower inherent vertical noise is key when making quality and precise mask tests. Vertical noise can cause random increases (spikes) in all areas of the signal, including trigger timing issues. Figure 4 below shows test results in just 6 seconds, capturing 3 elusive failures out of one million waveforms sampled. A consistent trigger point is vital to prevent jitter and drift of the waveforms. If a signal drifts outside the mask limits due to noise and/or trigger jitter, mask testing will analyze the oscilloscope-induced error components as a failure, thereby corrupting the test results. A low noise floor is essential to attain the precision and reliability of Six Sigma testing.

 Mask Testing

Figure 3 - Mask testing to 6.2 sigma resolution takes only seconds using an InfiniiVision scope with a mask test rate of 270,000 waveforms/s


Conclusion –

Not only does Keysight provide the fastest, low-noise mask testing performance in the market, but the mask test application on InfiniiVision scopes also has a variety of features for customizing your measurements. The Keysight mask testing software allows you to setup the mask test to run for a specified time, until a certain sigma threshold is reached, continue running upon a failure, stop on a failure, or save the data on a failure. This allows you to run a complete six sigma test in around one second. If a failure occurs the waveform can be set to automatically stop or saved for viewing and later analysis work. The capability to assure the quality of products to Six Sigma in 1.1 seconds saves time and effort in R&D and manufacturing. In R&D environments, engineers can test signals they are developing through many waveform repetitions spending less time but still ensuring signal stability. The more waveforms they can test, the more confidence they have that the design functions correctly. In manufacturing environments engineers must test signals to ensure customers receive reliable products. Your company can save manpower hours and can invest the capital in profitable initiatives, such as new product design. At the same time, customer satisfaction will increase as you produce high-quality products and move them quickly into the market.