# Find discontinuities and lift up or pull down the part after the discontinuity

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lena kappa on 13 Dec 2021
Commented: Jan on 24 Dec 2021
Hi everyone i have a singal with discontinuities.Does anyone know how can i find the discontinuities and at those points lift up or pull down the remaining signal?
Jan on 14 Dec 2021
I do noit see the steps in your diagram.

Jan on 13 Dec 2021
x = linspace(1, 10*pi, 200);
y = sin(x);
y(60:90) = y(60:90) + 1;
y(120:180) = y(120:180) - 1;
yOrig = y;
limit = 0.2;
dy = [0, diff(y)];
jump = strfind(abs(dy) > limit, [false, true, false]);
for ijump = 1:numel(jump)
k = jump(ijump);
y(k+1:end) = y(k+1:end) - dy(k+1);
end
figure
plot(x, yOrig, '-r', x, y, 'bo')
y2 = lowpass(y, 30, 200);
plot(x, y2, 'c+')
Jan on 24 Dec 2021
@lena kappa: See the documentation of lowpass:
y = lowpass(x,fpass,fs) specifies that x has been sampled at a rate of fs hertz. fpass is the passband frequency of the filter in hertz.
The result is stable over a wide range of parameters.

### More Answers (1)

Image Analyst on 13 Dec 2021
Image Analyst on 15 Dec 2021
I guess those were just some parameters to cause a chunk of the waveform to shift by a reasonable amount.