## Frequency, amplitude, phase and mean value of sine wave

Version 1.0.0.0 (2.46 KB) by
The function sinfapm evaluates parameters of sampled sine wave

Updated 14 May 2008

The function sinfap.m evaluates frequency, amplitude, phase and mean value of a uniformly sampled harmonic signal
x(t) = a.sin(2.pi.f.t + phi) + x_m
It uses a vector version of 3-point formulae derived by application of
Z-transform (see [1]) for finding amplitude and frequency of a signal.
If more than two output parameters are to be determined, all of them are optimized in the least squares sense by the function LMFnlsq.

Calls:
frq = sinfapm(x,fs); % Get only frequaency of sine-wave
[frq,amp] = sinfapm(x,fs); % Get frequency and amplitude
[frq,amp,phi] = sinfapm(x,fs); % Get frequency, amplitude and phase
[frq,amp,phi,ave] = sinfapm(x,fs); % ditto plus mean value
The set of more than two output parameters can be found by calling
[frq,amp,phi] = sinfapm(x,fs,Name_1,Val_1,Name_2,Val_2, ...);
[frq,amp,phi,ave] = sinfapm(x,fs,Name_1,Val_1,Name_2,Val_2, ...);

Input arguments:
x % vector of samples
fs % sampling frequency [Hz]
Name_i % name of the i-th optional parameter for optimization
Val_i % value of the i-th optional parameter (see function LMFnlsq)
Output arguments:
frq % frequency of x [Hz]
amp % amplitude of x
phi % phase in radians
Examples:
[f,a,phi,ave] = sinfapm([1.3633;-.2428;-0.9705;1.8130;-1.9631],10);
% f = 4.0000
% a = 2.0000
% phi = 0.7500
% ave = -2.2806e-005
[f,a,phi] = sinfapm([.707,1,.707,0],20,'Xtol',1e-4);
% f = 2.5001
% a = 0.9999
% phi = 0.7853 % pi/4 = 0.785398...

### Cite As

Miroslav Balda (2023). Frequency, amplitude, phase and mean value of sine wave (https://www.mathworks.com/matlabcentral/fileexchange/19902-frequency-amplitude-phase-and-mean-value-of-sine-wave), MATLAB Central File Exchange. Retrieved .

##### MATLAB Release Compatibility
Created with R2008a
Compatible with any release
##### Platform Compatibility
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Version Published Release Notes
1.0.0.0