spect

Compute the single sided amplitude and phase spectrums.

Syntax

func_as = spect(func, Fs)
func_as = spect(func, Fs, ...)
[f, func_as] = spect(func, Fs)
[f, func_as] = spect(func, Fs, ...)
[f, func_as, func_ps] = spect(func, Fs)
[f, func_as, func_ps] = spect(func, Fs, ...)

Description

spect computes the single-sided amplitude and phase spectrums of a 1, 2, or 3 dimensional input signal. If the optional input 'Dim' is not specified, the spectrum is computed along the first non-singleton dimension. For example, running the commands

% define signal
Fs = 10e6;              % [Hz]
dt = 1 / Fs;            % [s]
t = 0:dt:(1000 * dt);   % [s]
signal = 10 * sin(0.5e6 * 2 * pi * t) + 5 * sin(1e6 * 2 * pi * t) + 2 * sin(2.5e6 * 2 * pi * t);

% calculate spectrum
spect(signal, Fs, 'Plot', [true, false]);

will produce the following amplitude spectrum.

Inputs

func	signal to analyse
Fs	sampling frequency [Hz]

Optional Inputs

Optional 'string', value pairs that may be used to modify the default computational settings.

Input	Valid Settings	Default	Description
'Dim'	(integer scalar)	first non-singleton dimension	Dimension over which the spectrum is computed.
'FFTLength'	(integer scalar)	signal length	Length of the FFT. If the set length is larger than the signal length, the signal is zero padded. If the set length is smaller than the signal length, the default value is used instead.
'PowerTwo'	(Boolean scalar)	false	Boolean controlling whether the FFT length is forced to be the next highest power of 2.
'Plot'	(Boolean scalar or two element vector)	false	Boolean controlling whether the amplitude and phase spectrums are plotted. Can be given as a two element array to control the display of the amplitude and phase spectrums, respectively.
'Unwrap'	(Boolean scalar)	false	Boolean controlling whether the phase spectrum is unwrapped.
'Window'	(string)	'Rectangular'	Parameter string controlling the window type used to filter the signal before the FFT is taken. Any valid input types for getWin may be used.

Outputs

f	frequency array
func_as	single sided amplitude spectrum
func_ps	single sided phase spectrum

Examples

• Defining A Gaussian Sensor Frequency Response
• The Doppler Effect
• Filtering A Delta Function Input Signal
• Image Reconstruction With Compensation For Acoustic Absorption
• Source Smoothing
• Filtering A Delta Function Input Signal
• Modelling Power Law Absorption

See Also

smooth, filterTimeSeries