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Computes the single-sided, scaled amplitude spectrum of a real-valued time-domain signal and returns the amplitude spectrum as magnitude and phase.

Details  Examples

	Signal specifies the input time-domain signal, usually in volts. The time-domain record must contain at least three cycles of the signal for a valid estimate.
	unwrap phase, when TRUE, enables phase unwrapping on the output Amp Spectrum Phase. The default is TRUE. If unwrap phase is FALSE, this VI does not unwrap the output phase.
	dt is the sample period of the time-domain signal, usually in seconds. LabVIEW defines dt as 1/fs, where fs is the sampling frequency of the time-domain signal.
	Amp Spectrum Mag returns the single-sided power spectrum. If the input signal is in volts (V), Amp Spectrum Mag has units of volts-rms (Vrms). If the input signal is not in volts, Amp Spectrum Mag has units of the input signal unit-rms squared.
	Amp Spectrum Phase is the single-sided amplitude spectrum phase in radians.
	df is the frequency interval of the power spectrum in hertz, if dt is in seconds.

Amplitude and Phase Spectrum Details

The Amplitude and Phase Spectrum VI computes the amplitude spectrum using the following equation:

where n is the number of points in Signal.

This VI then computes Amp Spectrum Mag using the following equation:

Amp Spectrum Mag = |amplitude spectrum|

This VI computes Amp Spectrum Phase using the following equation:

Amp Spectrum Phase = phase(amplitude spectrum)

Examples

Refer to the following VIs for examples of using the Amplitude and Phase Spectrum VI:

• Realtime Amplitude Spectrum VI: labview\examples\ptbypt\PtByPt_No_HW.llb
• FFT and Power Spectrum Units VI: labview\examples\measure\maxmpl.llb