Average Moving filter in Simulink

Hey!

I don't have a DSP System Toolbox / Statistics, and I would like to create an average moving filter, and tune it.

I would appreciate any help, and thank in advance!

[Mathieu NOE]

hello

you can use a FIR filter of length N with 1/N values for all taps

other window are also doable if you want to weight the input data differently (hanning / hamming / kaiser etc...)

Model FIR filters - Simulink - MathWorks France

Answer 1

[Jon]

You could do it like this using just the discrete transfer function block included with Simulink>Discrete>Discrete Transfer Fcn, for example for the moving average of last 3 values

[Jon]

You could also include the 1/N scaling that I put in as a gain within the discrete transfer numerator values, so in the above example make all of the coefficients equal to 1/3, but I thought the gain made this a little more obvious

[Jon]

You could also make the numerator polynomial be [1 1 1 0], and include the current sample in the moving average window, this would give you direct feedthrough which you may or may not want.

[Jon]

You could also do the equivalent of what I show above using the Simulink>Discrete>Discrete FIR Filter, as @Mathieu NOE suggests, using coefficients are in terms of z^(-n), rather than a numerator and denominator using z^(n) as I did.

Answer 2

[Sulaymon Eshkabilov]

Why not use MATLAB code, e.g.:

t=linspace(0,2*pi);
S = sin(t);       % Signal 
R=randn(1,100);   % Noise
S = S+R*.5;       % Signal noise affected  
N = 3;            % 3-point moving average
S_ma(1)=S(1);
S_ma(2)=sum(S(1:3))/N;
for ii = 3:numel(R)
    S_ma(ii)=(S(ii-2)+S(ii-1)+S(ii))/N;
end
plot(t, S)
hold on
plot(t,S_ma, 'r','LineWidth', 2)
% Compare to the MATLAB's moving average filter from finance toolbox
S_mat = movavg(S.', 'simple', N);
plot(t, S_mat, 'k--*')
legend('Signal', 'Code: moving average', 'Matlab"s movavg fcn', 'location', 'best')
grid on
xlabel('t')
ylabel('Signal: S(t)')

[Jon]

I think the OP was asking how to do it in Simulink, rather than as a MATLAB calculation

[Kazem]

Use it as MATLAB funciton in Simulink