None 
4000 
No scalar measurement is performed. 
Frequency 
2 
Corresponds to the
NISCOPE_VAL_FREQUENCY
C or C++ command. 1.0 divided by the period, in hertz.

Average Frequency 
1016 
Corresponds to the
NISCOPE_VAL_AVERAGE_FREQUENCY
C or C++ command. 1.0 divided by the average period, in hertz.

FFT Frequency 
1008 
Corresponds to the
NISCOPE_VAL_FFT_FREQUENCY
C or C++ command.
The FFT amplitude spectrum is calculated using a splitradix real FFT, and the frequency corresponding to the maximum amplitude is returned. If the input waveform size is not a power of two, the waveform is zero padded to the next higher power of two. The frequency resolution is sampling rate / number of points.
The DC bin of the FFT is ignored when searching for the maximum amplitude, so the FFT frequency should ignore any DC offsets. However, the zero padding used in the FFT measurement can introduce other low frequency components if the waveform has a large DC offset. To avoid problems, make sure the
Horizontal Actual Record Length
property is a power of 2, so no zero padding occurs. This property can be fetched using
niScope Actual Record Length. Alternatively, configuring the digitizer for AC coupling solves the problem.

Period 
3 
Corresponds to the
NISCOPE_VAL_PERIOD
C or C++ command.
Finds the time, in seconds, between the first and third mid reference level crosspoints. A hysteresis window is applied when finding crosspoints. The mid reference level is 50% by default and is set with the
Channel Based Mid Ref Level
property.

Average Period 
1015 
Corresponds to the
NISCOPE_VAL_AVERAGE_PERIOD
C or C++ command.
Up to 256 mid reference level crossings are found on the waveform using a digital hysteresis. The time difference between the last crossing and the first crossing is divided by the number of periods found in the waveform. The last crossing is defined as the last crossing in the waveform with the same slope as the first crossing, so an integer number of periods exist in the waveform.

Rise Time 
0 
Corresponds to the
NISCOPE_VAL_RISE_TIME
C or C++ command.
The time span, in seconds, from when the waveform crosses the low reference level until it crosses the high reference level. The measurement starts at the left edge of the waveform and finds all low reference level crossings until a high reference level crossing. The final low reference level crossing is used in the calculation.
The reference levels are specified by
Channel Based Low Ref
and
Channel Based High Ref, and their default values are 10% and 90%.

Fall Time 
1 
Corresponds to the
NISCOPE_VAL_FALL_TIME
C or C++ command.
The time span, in seconds, from when the waveform crosses the high reference level until it crosses the low reference level. The measurement starts at the left edge of the waveform and finds all high reference level crossings until a low reference level crossing. The final high reference level crossing is used in the calculation.
The reference levels are specified by
Channel Based Low Ref
and
Channel Based High Ref, and their default values are 10% and 90%.

Rising Slew Rate 
1010 
Corresponds to the
NISCOPE_VAL_RISE_SLEW_RATE
C or C++ command.
The high reference voltage minus the low reference voltage is divided by the risetime calculation.

Falling Slew Rate 
1011 
Corresponds to the
NISCOPE_VAL_FALL_SLEW_RATE
C or C++ command.
The low reference voltage minus the high reference voltage is divided by the falltime calculation. The result is always negative.

Overshoot 
18 
Corresponds to the
NISCOPE_VAL_OVERSHOOT
C or C++ command.
The measurement is taken on the first edge of the waveform. If two edges exist, the algorithm finds the time interval from the first edge until one half the time to the second edge. The local maxima and minima are found in this interval. If only one edge is present in the waveform, the local maximum and minimum is found between the first edge and the end of the waveform.
If the first edge is positive sloped, overshoot = 100 × (local maximum  voltage high) / voltage amplitude.
If the first edge is negative sloped, overshoot = 100 × (voltage low  local minimum) / voltage amplitude.

Preshoot 
19 
Corresponds to the
NISCOPE_VAL_PRESHOOT
C or C++ command.
The measurement is taken on the second edge of the waveform if two edges exist. The algorithm finds the time interval from the middle time between the two edges until the second edge. The local maxima and minima are found in this interval. If only one edge is present in the waveform, the local maximum and minimum are found from the start of the waveform to the first edge.
If the edge is negative sloped, preshoot = 100 × (local maximum  voltage high) / voltage amplitude.
If the edge is positive sloped, preshoot = 100 × (voltage low  local minimum) / voltage amplitude.

Voltage RMS 
4 
Corresponds to the
NISCOPE_VAL_VOLTAGE_RMS
C or C++ command.
Voltage RMS is determined by the following equation:
Voltage RMS = √[( Σ waveform[i]^{2}) / numPoints]

Voltage Cycle RMS 
16 
Corresponds to the
NISCOPE_VAL_VOLTAGE_CYCLE_RMS
C or C++ command.
Voltage Cycle RMS = √[(Σ waveform[i]^{2}) / pointsPerPeriod]
The number points in a period is calculated using the equation:
pointsPerPeriod = period / dt
where period is the measured period of the signal and dt is the time between two points. The result will then be converted to an integer from a floating point value.

AC Estimate 
1012 
Corresponds with the
NISCOPE_VAL_AC_ESTIMATE
C or C++ command.
The DC estimate is subtracted from the waveform, and a Hanning window is applied to give a processed waveform. The RMS voltage is calculated with the following equation:
√([Σ processed waveform[i]^{2}] / [numPoints × enbw × cg^{2}]),
where the equivalent noise bandwidth (enbw) for the Hanning window is 1.5, and the coherent gain (cg) is 0.5.
This algorithm minimizes the effect of an uneven number of waveform cycles in the measurement, which could arbitrarily increase or decrease the RMS value.

FFT Amplitude 
1009 
Corresponds to the
NISCOPE_VAL_FFT_AMPLITUDE
C or C++ command.
The FFT amplitude spectrum is calculated using a splitradix real FFT, and the maximum amplitude is returned. If the input waveform size is not a power of two, the waveform is zeropadded to the next highest power of two. For best results, verify that your actual record length is a power of 2.

Voltage Average 
10 
Corresponds to the
NISCOPE_VAL_VOLTAGE
C or C++ command.
The voltage average is determined by the following equation:
Voltage Average = Σ waveform[i] / numPoints

Voltage Cycle Average 
17 
Corresponds to the
NISCOPE_VAL_VOLTAGE_CYCLE_AVERAGE
C or C++ command.
Voltage Cycle Average = ( Σ waveform[i]) / pointsPerPeriod
The number of points in a period in volts is calculated using the following equation:
pointsPerPeriod = period / dt
where period is the measured period of the signal and dt is the time between two points. The result will then be converted to an integer from a floating point value.

DC Estimate 
1013 
Corresponds to the
NISCOPE_VAL_DC_ESTIMATE
C or C++ command.
A Hanning window is applied to give a processed waveform and the voltage average is calculated with the following equation:
voltage average = (Σ processed waveform[i]) / (cg × numPoints),
where the coherent gain (cg) of the Hanning window is 0.5  the DC gain of the window.
The algorithm minimizes the effect of an uneven number of waveform cycles. For example, performing a simple voltage average on 5.5 cycles of a sine waveform gives a slightly incorrect DC estimate if the extra half cycle is not evenly divided between the positive and negative portions of the sine wave.

Voltage Max 
6 
Corresponds to the
NISCOPE_VAL_VOLTAGE_MAX
C or C++ command.
Searches the waveform for its maximum point.

Voltage Min 
7 
Corresponds to the
NISCOPE_VAL_VOLTAGE_MIN
C or C++ command.
Searches the waveform for the minimum point in volts.

Voltage PeaktoPeak 
5 
Corresponds to the
NISCOPE_VAL_VOLTAGE_PEAK_TO_PEAK
C or C++ command.
The maximum voltage minus the minimum voltage in volts.

Voltage High 
8 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HIGH
C or C++ command.
Uses the lastacquisition histogram method, where the voltage high result is the voltage of the histogram bin with the maximum number of hits above 60% of the waveform's voltage peaktopeak value. This calculation is useful for ignoring the overshoot and preshoot on square waves.

Voltage Low 
9 
Corresponds to the
NISCOPE_VAL_VOLTAGE_LOW
C or C++ command.
The last acquisition histogram method is used where the voltage low result is the voltage of the histogram bin with the maximum number of hits below 40% of the waveform's voltage peaktopeak value. This calculation is useful for ignoring the overshoot and preshoot on square waves.

Voltage Amplitude 
15 
Corresponds to the
NISCOPE_VAL_VOLTAGE_AMPLITUDE
C or C++ command.
The voltage amplitude is calculated by the voltage high minus the voltage low.

Voltage Top 
1007 
Corresponds to the
NISCOPE_VAL_VOLTAGE_TOP
C or C++ command.
If the histogram bin corresponding to voltage high has over fiver percent of the total hits, the voltage high result is returned. Otherwise, the voltage maximum calculation is returned. Otherwise, the voltage maximum calculation is returned. This allows using the voltage top to get a reasonable answer for either a square wave (ignoring the overshoot and preshoot) or a triangle wave (where a histogram fails).

Voltage Base 
1006 
Corresponds to the
NISCOPE_VAL_VOLTAGE_BASE
C or C++ command.
If the histogram bin corresponding to voltage low has over five percent of the total hits, the voltage low result is returned. Otherwise, the voltage minimum calculation is returned. Otherwise, the voltage minimum calculation is returned. This allows using the voltage base to get a reasonable answer for either a square wave (ignoring the overshoot and preshoot) or a triangle wave (where a histogram fails).

Voltage BasetoTop 
1017 
Corresponds to the
NISCOPE_VAL_VOLTAGE_BASE_TO_TOP
C or C++ command.
Voltage BasetoTop is calculated by subtracting voltage base from voltage top.

Negative Width 
11 
Corresponds to the
NISCOPE_VAL_WIDTH_NEG
C or C++ command.
The time difference between the first two mid reference level crossings, where the slopes are negative and positive, respectively. A digital hysteresis is used when finding the crosspoints.

Positive Width 
12 
Corresponds to the
NISCOPE_VAL_WIDTH_POS
C or C++ command.
The time difference, in seconds, between the first two mid reference level crossings, where the slopes are positive and negative respectively. A digital hysteresis is used when finding the crosspoints.

Negative Duty Cycle 
13 
Corresponds to the
NISCOPE_VAL_DITY_CYCLE_NEG
C or C++ command. The negative duty cycle is the negative width divided by the period times 100.

Positive Duty Cycle 
14 
Corresponds to the
NISCOPE_VAL_DUTY_CYCLE_POS
C or C++ command. Positive duty cycle is the positive width divided by the period times 100.

Integral 
1005 
Corresponds to the
NISCOPE_VAL_INTEGRAL
C or C++ command. Performs numerical integration using Simpson's rule, in units of volts × seconds.

Area 
1003 
Corresponds to the
NISCOPE_VAL_AREA
C or C++ command.
Calculates the area between two points using the following equation:
area = voltage average × numPoints × delta time

Cycle Area 
1004 
Corresponds to the
NISCOPE_VAL_CYCLE
C or C++ command.
Uses the following equation:
Cycle area = voltage cycle average × pointsPerPeriod × dt
where
pointsPerPeriod
=
period
/
dt.

Time Delay 
1014 
Corresponds to the
NISCOPE_VAL_TIME_DELAY
C or C++ command.
The algorithm finds the first time, in seconds, that the waveform from the channel specified by the
channel
parameter crosses its midreference level. Next, the algorithm finds the first two times that the waveform from the
Other Channel
property crosses its midreference level.
Note
If you want to measure from falling edge to falling edge, you can invert the data from both channels by adding a processing step and using the array measurement gain with a value of 1. With this method, you can also measure from rising edge to falling edge or from falling edge to rising edge by inverting a signal on one of the two channels.
The midreference level is stored on a per channel basis, and midreference levels do not need to be the same. All reference levels use a digital hysteresis.

Phase Delay 
1018 
Corresponds to the
NISCOPE_VAL_PHASE_DELAY
C or C++ command.
Phase Delay
is the
time delay
divided by the period (of the waveform on the channel specified by the measurement node) times 360 degrees.

Low Ref Volts 
1000 
Corresponds to the
NISCOPE_VAL_LOW_REF_VOLTS
C or C++ command.
The voltage corresponding to the low reference level. If the
Reference Level Units
property is set to
Voltage, the value of the
Channel Based Low Ref Level
property is returned.
If the
Reference Level Units
property is set to
Percentage, the voltage is calculated with the method specified by the
Percentage Units Method
property.

Mid Ref Volts 
1001 
Corresponds to the
NISCOPE_VAL_MID_REF_VOLTS
C or C++ command.
The voltage corresponding to the mid reference level. If the
Reference Level Units
property is set to Voltage, the value of the
Channel Based Mid Ref
property is returned.
If the
Reference Level Units
is set to
Percentage, the voltage is calculated with the method specified by the
Percentage Units Method
property.

High Ref Volts 
1002 
Corresponds to the
NISCOPE_VAL_HIGH_REF_VOLTS
C or C++ command.
The voltage corresponding to the high reference level. If the
Reference Level Units
property is set to
Voltage, the value of the
Channel Based High Ref
property is returned.
If the
Reference Level Units
property is set to
Percentage, the voltage is calculated with the method specified by the
Percentage Units Method
property.

Volt. Hist. Mean 
2000 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MEAN
C or C++ command.
Histogram Mean = [∑(bin hits × bin value) ] / volt hist hits
The bin value is the center voltage value of the histogram bin.

Volt. Hist. Stdev 
2001 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_STDEV
command.
Histogram Stdev = √∑[bin hits × (bin value  histogram mean)^{2}]/(total hits  1)

Volt. Hist. Median 
2003 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MEDIAN
C or C++ command.
The bin value where half the histogram hits are above it and half the histogram hits are below.

Volt Hist. Mode 
2010 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MODE
C or C++ command.
The bin value with the most hits. If there is a tie, the lower voltage or time value is returned.

Volt. Hist. Max 
2005 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MAX
C or C++ command.
The highest bin value with at least one hit.

Volt. Hist. Min 
2006 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MIN
C or C++ command.
The lowest bin value with at least one hit.

Volt. Hist. Peak to Peak 
2002 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_PEAK_TO_PEAK
C or C++ command.
Histogram maximum minus the histogram minimum.

Volt. Hist. Mean + Stdev 
2007 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MEAN_PLUS_STDEV
C or C++ command.
The percentage of hits in the histogram between mean minus the standard deviation and mean plus the standard deviation. The percentage is returned in the range 0100.

Volt. Hist. Mean + 2 Stdev 
2008 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MEAN_PLUS_2_STDEV
C or C++ command.
The percentage of hits in the histogram between the mean minus two times the standard deviation and the mean plus to times the standard deviation.
The percentage is returned in the range 0100.

Volt. Hist. Mean + 3 Stdev 
2009 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_MEAN_PLUS_3_STDEV
C or C++ command.
The percentage of hits in the histogram between the mean minus three times the standard deviation and the mean plus three times the standard deviation. The percentage is returned in the range 0100.

Volt. Hist. Hits 
2004 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_HITS
C or C++ command.
Number of points in the histogram.

Volt. Hist. New Hits 
2011 
Corresponds to the
NISCOPE_VAL_VOLTAGE_HISTOGRAM_NEW_HITS
C or C++ command.
Number of points added to the histogram by the most recent acquisition.

Time Hist. Mean 
3000 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MEAN
C or C++ command.
Histogram Mean = [ Σ (bin hits × bin value) ] / time hist hits.
The bin value is the center time value of the histogram bin.

Time Hist. Stdev 
3001 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_STDEV
C or C++ command.
Histogram Stdev = √Σ[bin hits × (bin value  histogram mean)^{2}]/(total hits  1)

Time Hist. Median 
3003 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MEDIA
C or C++ command.
The bin value where half the histogram hits are above it and half the histogram hits are below.

Time Hist. Mode 
3010 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MODE
C or C++ command.
The bin value with the most hits. If there is a tie, the lower voltage or time value is returned.

Time Hist. Max 
3005 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MAX
C or C++ command.
The highest bin value with at least one hit.

Time Hist. Min 
3006 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MIN
C or C++ command.
The lowest bin value with at least one hit.

Time Hist. PeaktoPeak 
3002 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_PEAK_TO_PEAK
C or C++ command.
Histogram maximum minus the histogram minimum.

Time Hist. Mean + Stdev 
3007 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MEAN_PLUS_STDEV
C or C++ command.
The percentage of hits in the histogram between mean minus the standard deviation and mean plus the standard deviation. The percentage is returned in the range 0100.

Time Hist. Mean + 2 Stdev 
3008 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MEAN_PLUS_2_STDEV
C or C++ command.
The percentage of hits in the histogram between the mean minus two times the standard deviation and the mean plus two times the standard deviation. The percentage is returned in the range 0100.

Time Hist. Mean + 3 Stdev 
3009 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_MEAN_PLUS_3_STDEV
C or C++ command.
The percentage of hits in the histogram between the mean minus three times the standard deviation and the mean plus three times the standard deviation. The percentage is returned in the range 0100.

Time Hist. Hits 
3004 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_HITS
C or C++ command.
Number of points in the histogram.

Time Hist. New Hits 
3011 
Corresponds to the
NISCOPE_VAL_TIME_HISTOGRAM_NEW_HITS
C or C++ command.
Number of points added to the histogram by the most recent acquisition.
