Table Of Contents

Measurement Types

Version:
    Last Modified: May 17, 2018

    The following measurement types are available when creating oscilloscope channels with InstrumentStudio.

    Amplitude Mid Ref Volts Mean Negative Duty Cycle
    Peak-to-Peak Low Ref Volts Median Positive Pulse Width
    High Positive Undershoot Cycle RMS Negative Pulse Width
    Low Negative Undershoot Cycle Mean Rise Time
    Maximum Positive Overshoot Period Fall Time
    Minimum Negative Overshoot Frequency Rise Rate
    High Ref Volts RMS Positive Duty Cycle Fall Rate

    Amplitude

    The voltage High measurement minus the voltage Low measurement.

    Peak-to-Peak

    The Maximum measurement minus the Minimum measurement.

    High

    The High measurement is calculated using the selected High-Low method. If you select the Histogram High-Low method, the High measurement is calculated using the most common value found in the upper 40% of the waveform. If you select the Peak High-Low method, the High measurement is calculated using the waveform's Maximum measurement value.

    Low

    The Low measurement is calculated using the selected High-Low method. If you select the Histogram High-Low method, the Low measurement is calculated using the most common value found in the lower 40% of the waveform. If you select the Peak High-Low method, the Low measurement is calculated using the waveform's Minimum measurement value.

    Maximum

    The maximum value found in the waveform.

    Minimum

    The minimum value found in the waveform.

    High Ref Volts

    The voltage of the signal at the High reference level. If you set the reference level unit to Percentage, the High Ref Volts measurement is calculated with the selected High-Low method. If you set the reference level unit to Volts, the voltage you set as the High reference level is used for the High Ref Volts measurement.

    Mid Ref Volts

    The voltage of the signal at the Mid reference level. If you set the reference level unit to Percentage, the Mid Ref Volts measurement is calculated with the selected High-Low method. If you set the reference level unit to Volts, the voltage you set as the Mid reference level is used for the Mid Ref Volts measurement.

    Low Ref Volts

    The voltage of the signal at the Low reference level. If you set the reference level unit to Percentage, the Low Ref Volts measurement is calculated with the selected High-Low method. If you set the reference level unit to Volts, the voltage you set as the Low reference level is used for the Low Ref Volts measurement.

    Positive Undershoot

    Negative Undershoot

    Positive Overshoot

    Negative Overshoot

    RMS

    The true root mean square voltage over the entire waveform. This measurement uses the following formula:

    RMS = sqrt[(sum(square(waveform[i]) / number of points)))]

    Mean

    The mean over the entire waveform.

    Median

    The median over the entire waveform. The points in the waveform are sorted according to the following formulas:

    Number of Points Returned Value
    Odd waveform[(n-1)/2]
    Even (waveform[m/2] + waveform[n/2 +1]) / 2

    Cycle RMS

    The true root mean square voltage over the first cycle of the waveform. The first cycle is determined using the values specified by the High, Mid, and Low reference levels. This measurement uses the following formula:

    Cycle RMS = sqrt[(sum(square(waveform[i]) / number of points)))]

    where waveform is all the points in the first cycle of the waveform.

    Cycle Mean

    The voltage average over the first cycle of the waveform. The values you specify in the High, Mid, and Low reference level fields in the Settings tab of the Measurements window determine the first cycle.

    Period

    The time of the first two Mid reference level crossings in the same direction. A hysteresis is applied using the values specified by the High or Low reference levels.

    Frequency

    1.0 divided by the Period measurement, in hertz.

    Positive Duty Cycle

    The Positive Pulse Width divided by the Period times 100.

    Positive Duty Cycle = (Positive Pulse Width/Period) × 100

    Negative Duty Cycle

    The Negative Pulse Width divided by the Period times 100.

    Negative Duty Cycle = (Negative Pulse Width/Period) × 100

    Positive Pulse Width

    The time difference in seconds between the first two Mid reference level crossings, where the first slope is positive and the second is negative. The High or Low reference levels are used to apply a hysteresis.

    Negative Pulse Width

    The time difference in seconds between the first two Mid reference level crossings, where the first slope is negative and the second is positive. The High or Low reference levels are used to apply a hysteresis.

    Rise Time

    The time span of the first rising edge of the waveform to cross the Low reference level until it crosses the High reference level. The time span starts from the Low reference level crossing immediately preceding the High reference level crossing.

    Fall Time

    The time span between when the first falling edge of the waveform crosses the High reference level to when the same falling edge crosses the Low reference level.

    Rise Rate

    The Rise Time divided by the High reference level minus the Low reference level.

    Rise Rate = Rise Time / (High reference level - Low reference level)

    Fall Rate

    The Fall Time divided by the High reference level minus the Low reference level.

    Fall Rate = Fall Time / (High reference level - Low reference level)


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