You can use Reference Levels and Gating to customize the measurements displayed in the measurement table.

  1. Click Add/Remove in the Measurements section of an oscilloscope panel.
  2. Click the Settings tab of the Measurements window to configure oscilloscope measurements.

Gating

Use gating options to select the region of captured data that is used to perform measurements. This region of data appears in the measurement table.

  • Screen—Performs measurements only on the data that is visible in the time domain graph of the large panel.
  • Record—Performs measurements on the full data record.
  • Custom—Performs measurements only on the data between set positions. You can configure custom gating positions with time values that are relative to the trigger of the data capture starting point.
  • Position 1—Sets the first position of the gated data relative to the trigger to calculate measurements.
  • Position 2—Sets the second position of the gated data relative to the trigger to calculate measurements.

    • Reference Levels

    You can customize the oscilloscope measurements that appear on the measurement table. Adjust the Reference Levels and the High-Low Method from the Settings tab of the Measurements window.

    High, Mid, and Low Reference Levels

    Reference levels are range values that divide a waveform into high, middle, and low sections by intersecting the waveform at a specified amplitude. You can use reference levels to do the following tasks:
    • Ascertain rise and fall times
    • Calculate waveform cycles
    • Customize certain oscilloscope measurement types

    In InstrumentStudio, you must set reference levels by absolute levels or by the percentage of the waveform that you want to acquire. The following oscilloscope measurement types are calculated using reference levels:

    Reference Level Unit

    Use the Reference Level Unit settings to specify whether reference levels are interpreted as percentages of the waveform or as absolute levels.

  • Percentage—Interprets the reference levels as a percentage using the selected High-Low method.
  • Absolute—Interprets the reference levels as absolute levels, such as volts.

    • High-Low Method

    If you set the Reference Level Unit setting to Percentage, you can configure how the state levels are computed by selecting the High-Low method. The following configuration options are available:

  • Auto-select—Determines whether the histogram bins that correspond to the high and low state levels each have over 5% of the total hits. If so, the device returns those results. If not, the device uses the Peak High-Low method. The Auto-select High-Low method provides an answer for one of the following waves:
    • A square wave, by ignoring the overshoot and the undershoot
    • A triangle wave, where the Histogram High-Low method fails
  • Histogram—Computes state levels using the histogram bins with the maximum number of hits in the upper and lower regions of the waveform. The upper and lower regions of the waveform include the upper and lower 40% of the peak-to-peak range.
  • Peak—Searches the waveform for its maximum and minimum levels.