AmpPhaseSpectrum
Advanced Analysis Library Only
AnalysisLibErrType AmpPhaseSpectrum (double inputArray[], ssize_t numberOfElements, int unwrap, double dt, double amplitudeSpectrum[], double phaseSpectrum[], double *df);
Purpose
Calculates the single-sided, scaled amplitude and phase spectra of a time-domain signal, X. AmpPhaseSpectrum calculates the amplitude spectrum as
and converts it to single-sided form. AmpPhaseSpectrum calculates the phase spectrum as
phase(FFT(X))
and converts it to single-sided form.
Parameters
| Input | ||
| Name | Type | Description |
| inputArray | double [] | The time-domain signal. |
| numberOfElements | ssize_t | Number of elements in the input array. Default Value: 1024. |
| unwrap | int | Controls the unwrapping of the phase spectrum. Specify a nonzero value or ENABLE_OPTION or select On in the function panel to enable phase wrapping. This is the default value. Specify 0 or DISABLE_OPTION or select Off in the function panel to disable phase unwrapping. (–Π ≤ phase ≤ +Π) |
| dt | double | Sampling period of the time-domain signal, usually in seconds. dt = 1/fs, where fs is the sampling frequency of the time-domain signal. Default Value: 1.0. |
| Output | ||
| Name | Type | Description |
| amplitudeSpectrum | double [] | Single-sided amplitude spectrum magnitude in volts, root-mean-square, if the input signal is in volts. If the input signal is not in volts, the results are in input signal units, root-mean-square. This array must be at least numberOfElements/2 elements long. |
| phaseSpectrum | double [] | Single-sided phase spectrum in radians. This array must be at least numberOfElements/2 elements long. |
| df | double | Points to the frequency interval, in Hertz, if dt is in seconds. df = 1/(numberOfElements × dt) |
Return Value
| Name | Type | Description |
| status | AnalysisLibErrType | A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants. |
Additional Information
Library: Advanced Analysis Library
Include file: analysis.h
LabWindows/CVI compatibility: LabWindows/CVI 3.1 and later