Hello Lancer, The following is taken from LabVIEW Help under Pulse Parameters:
X is the input sequence. X must meet the following conditions: =95=09The number of samples in X must be greater than or equal to 3. =95=09X should have a rising edge, a plateau, and a falling edge. =95=09The expected peak noise amplitude must be less than 50% of the expected amplitude. If the number of samples in X is less than 3, the VI sets all the pulse parameters to NaN and returns an error. If X does not contain a rising edge, plateau, and falling edge, the VI analyzes the data, assigns values to as many pulse parameters as it can identify, and sets parameters it cannot identify to NaN. The VI does not report this condition as an error. Note X can be a positive- or negative-going pulse. A histogram is used to determine top and base. If the difference between top and base is negative, the pulse is considered negative-going with a negative amplitude. If the data in X is noisy beyond the expected 50% amplitude, the VI does not have enough information to differentiate between glitches and pulse data and may assign incorrect values to the pulse parameters. Because it cannot be detected, the VI does not report this condition as an error. Note If the data is noisy, you can apply a median filter to the data before passing it to the Pulse Parameters VI. Refer to Noisy Pulse Analyzed with a Median Filter for more information about analysis with a median filter. Note When the X data is a constant value c, the VI sets the pulse parameters to the following values. amplitude =3D overshoot =3D undershoot =3D delay =3D duration =3D 0. top =3D base =3D c. risetime =3D falltime =3D slew rate =3D NaN. slew rate is the ratio between (90% amplitude - 10% amplitude) and the risetime. overshoot is the difference between the maximum value in the pulse and the topline. risetime is the time required to rise from 10% amplitude to 90% amplitude on the rising edge of the pulse. top is the line that best represents the values when the pulse is active, high, or on. For a negative-going pulse, top is less than base and results in a negative amplitude. For a positive-going pulse, top is larger than base and results in a positive amplitude. amplitude is the difference between top and base. base is the line that best represents the values when the pulse is inactive, low, or off and is the level closest to zero. For a negative-going pulse, base is larger than top and results in a negative amplitude. For a positive-going pulse, base is less than top and results in a positive amplitude. undershoot is the difference between the baseline and the minimum value in the pulse. error returns any error or warning from the VI. You can wire error to the Error Cluster From Error Code VI to convert the error code or warning into an error cluster. falltime is the time required to fall from 90% amplitude to 10% amplitude on the falling edge of the pulse. duration is the difference between the falling edge time and the rising edge time at which 50% amplitude occurs. delay is the difference between the time origin and the time at which 50% amplitude occurs on the rising edge of the pulse. Pulse Parameters Details Note The Cycle Average and RMS, Transition Measurements, Pulse Measurements, and Amplitude and Levels VIs provide more measurements than the Pulse Parameters VI, and you can configure each of those VIs. The waveform-related parameters are slew rate, overshoot, topline (top), amplitude, baseline (base), and undershoot. If y-axis units are volts, then slew rate has units of volts per sample. The time-related parameters are risetime, falltime, duration (width), and delay and are expressed in units of samples. Note The VI assumes the input pulse or pulse train has a bimodal, or two-state, distribution. Any input other than a bimodal input can lead to inconsistent results. The Pulse Parameters VI uses the following steps to calculate the output parameters. 1.=09Find the maximum and minimum values in the input sequence X. 2.=09Generate the histogram of the pulse with 1% range resolution. 3.=09Determine the upper and lower modes to establish the top and base values. 4.=09Find the overshoot, amplitude, and undershoot from top, base, maximum, and minimum values. 5.=09Scans X and determines the slew rate, risetime, falltime, duration, and delay. The Pulse Parameters VI interpolates duration and delay to obtain a more accurate result not only of duration and delay but also of slew rate, risetime, and falltime. If X contains a train of pulses, the Pulse Parameters VI uses the train to determine overshoot, top, amplitude, base, and undershoot but uses only the first pulse in the train to establish slew rate, risetime, falltime, duration, and delay. Note Because pulses commonly occur in the negative direction, the Pulse Parameters VI can discriminate between positive and negative pulses and can analyze the X sequence correctly. You do not need to preprocess the sequence before analyzing it. If none of these suggestions help, or if I=92m not correctly understanding your issue, please post the software and versions you are using, the applicable portions of your code, and any other information that may help, and I=92ll be happy to look further into it. Have a nice day! Robert M Applications Engineer National Instruments
