Table Of Contents

Measurement Types

Last Modified: January 3, 2019

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
Delta Time Setup Time Hold Time Crosspoint Voltage
Crosspoint Time FFT Frequency FFT Amplitude

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)

Delta Time

The time span from when the first edge of the waveform crosses the Mid reference level until the second edge of the waveform crosses the Mid reference level. The second edge can be configured to another channel.

Setup Time

The time span from when the waveform crosses the Mid reference level until the configured clock channel crosses the Mid reference level. The Setup Time measurement uses the crossing of the clock channel that is closest to the middle of the graph.

Hold Time

The time span from when the configured clock channel crosses the Mid reference level until the waveform crosses the Mid reference level. The Hold Time measurement uses the crossing of the clock channel that is closest to the middle of the graph.

Crosspoint Voltage

The voltage at which two waveforms intersect. The second waveform can be configured to another channel. The crosspoint voltage measurement uses the intersection closest to the middle of the graph.

Crosspoint Time

The time at which two waveforms intersect. The second waveform can be configured to another channel. The crosspoint time measurement uses the intersection closest to the middle of the graph.

FFT Amplitude

Calculates a real FFT and returns the maximum amplitude. The search ignores the DC bin of the FFT; peaks close to DC (but not in the DC bin) are detected.

FFT Frequency

Calculates a real FFT and returns the frequency that corresponds to the maximum amplitude. The search ignores the DC bin of the FFT; peaks close to DC (but not in the DC bin) are detected.


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