CNiIviScopeMeasurement::ReadWaveformMeasurement

Measurement Studio IVI

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CNiIviScopeMeasurement::
ReadWaveformMeasurement()

Public Function

Declared in:
NiIviScope.h

Declaration

inline double ReadWaveformMeasurement(
    const CString &channel,
    long int maxTime,
    long measurementFunction);

Description

Initiates an acquisition on all channels that you enable with the Channel.Configure function. It then waits for the acquisition to complete and returns the measurement for the channel you specify. If the oscilloscope did not complete the acquisition within the time period you specify with the maxTime parameter, the function throws an exception.

You call the FetchWaveformMeasurement function to obtain the measurements for each of the remaining enabled channels without initiating another acquisition.

Parameters

const CString &channel

The channel on which you want to obtain a waveform measurement.

long int maxTime

The maximum length of time in milliseconds in which to allow the operation to complete.

If the operation does not complete within this time interval, the function throws an exception. When this occurs, you can call Abort to cancel the operation and return the oscilloscope to the Idle state.

long measurementFunction

The waveform measurement you want the oscilloscope to perform.

The following list includes valid values:

CNiIviScope::RiseTime - The length of time for the first rising edge of the signal to rise from the low reference level to the high reference level.

CNiIviScope::FallTime - The length of time for the first falling edge of the signal to fall from the high reference level to the low reference level. CNiIviScope::Frequency - The frequency of one complete cycle in the waveform. CNiIviScope::Period - The frequency of one complete cycle in the waveform. CNiIviScope::VoltageRms - The true Root Mean Square voltage of the entire waveform. CNiIviScope::VoltagePeakToPeak - The absolute difference between the Voltage Max and the Voltage Min. CNiIviScope::VoltageMax - The maximum amplitude found in the entire waveform. CNiIviScope::VoltageMin - The minimum amplitude found in the entire waveform. CNiIviScope::VoltageHigh - The voltage that corresponds to 100% when you use the reference levels. The oscilloscope calculates this value using either the min/max or histogram methods. The min/max method uses the maximum value found. The histogram method uses the most common value found above the middle of the waveform. CNiIviScope::VoltageLow - The voltage that corresponds to 0% when you use the reference levels. The oscilloscope calculates this value using either the min/max or histogram methods. The min/max method uses the minimum value found. The histogram method uses the most common value found below the middle of the waveform. CNiIviScope::VoltageAverage - The arithmetic average amplitude of the entire waveform. CNiIviScope::WidthNeg - The length of time between the mid reference level points of the first negative pulse in the waveform. CNiIviScope::WidthPos - The length of time between the mid reference level points of the first positive pulse in the waveform. CNiIviScope::DutyCycleNeg - The ratio of the Width Negative to the Period of the first cycle in the waveform expressed as a percentage. Duty Cycle Negative = 100.0 x (Width Negative)/Period CNiIviScope::DutyCyclePos - The ratio of the Width Positive to the Period of the first cycle in the waveform expressed as a percentage. Duty Cycle Positive = 100.0 X (Width Positive)/Period CNiIviScope::Amplitude - The Voltage High less the Voltage Low in Volts over the entire waveform CNiIviScope::VoltageCycleRms - The true Root Mean Square voltage over the first cycle in the waveform. CNiIviScope::VoltageCycleAverage - The arithmetic average amplitude of the first cycle in the waveform. CNiIviScope::Overshoot - The relative waveform distortion which follows an edge transition. It is calculated using the following formula: For the rising edge, overshoot = ((local maximum - Voltage High)/Amplitude)*100%, where the local maximum is the maximum voltage of the signal in the first half of the time period that commences when the rising edge crosses the high reference level and concludes when the subsequent falling edge crosses the high reference level. For the falling edge, overshoot = ((Voltage Low - local minimum)/Amplitude)*100%, where the local minimum is the minimum value of the signal measured in the first half of the time period that commences when the falling edge crosses the low reference level and concludes when the subsequent rising edge crosses the low reference level. The instrument makes the measurement on the edge closest to the beginning of the waveform record. CNiIviScope::Preshoot - The relative waveform distortion which precedes an edge transition. It is calculated using the following formula: For the rising edge, preshoot = ((Voltage Low - local minimum)/Amplitude)*100%, where the local minimum is the minimum value of the signal measured in the second half of the time period that commences when the preceding falling edge crosses the low reference level and concludes when the rising edge crosses the low reference level. For the rising edge, preshoot = ((local maximum - Voltage High)/Amplitude)*100%, where the local maximum is the maximum voltage of the signal in the second half of the time period that commences when the preceding rising edge crosses the high reference level and concludes when the falling edge crosses the high reference level. The instrument makes the measurement on the edge closest to the beginning of the waveform record.

See Also Class Overview | Hierarchy Chart

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