How to find the Zero Crossing Rate of a signal?

Please, I want to determine the Zero Crossing Rate of an Acoustic Signal. I would be glad if someone could provide me with a code in Matlab to carry out such exercise,

Thank you in advance.

Answer 1

[Star Strider]

Try this:

t = linspace(0, 5, 500).^3;                                 % Time Vector
s = sin(2*pi*t*0.2);                                        % 10 Hz Sine Curve

zx = find(diff(sign(s)));                                   % Zero-Crossing Indices To ‘t’

for k = 1:numel(zx)
    idx_rng = max(zx(k)-1, 1):min(zx(k)+1,numel(t));
    tzro(k) = interp1(s(idx_rng), t(idx_rng), 0);           % Exact Zero Crossings
end

zx_rate = gradient(tzro);                                   % Calculate Rate

figure
yyaxis left
plot(t, s, '-b')
hold on
plot(tzro, zeros(size(tzro)), 'xr')
hold off
yyaxis right
plot(tzro, zx_rate, 'LineWidth',2)
grid
legend('Signal','Zero-Crossings','Zero-Crossing Rate')
axis('tight')

Once you have the zero-crossings, you can do whatever processing on them that you want.

.

Answer 2

[Frantz Bouchereau]

Signal Processing Toolbox in MATLAB R2021b ships a new zerocrossrate function that you can use to find zero crossing rates of a signal.

Answer 3

[Mathieu NOE]

hello

i am not sure what a "rate" can be about zero crossing, but at least maybe this code will give you access to zero or whatever threshold value crossing detection

positive slope and negative slope are detected separatly

hope it helps !

[Kwaku Owusu]

Thank you very much.

[Mathieu NOE]

you're welcome

would you accept my answer ? tx

[Kwaku Owusu]

Please, I cannot see the code provided. Thank you.