Plot problem after DC offset

Hi all,

I am plotting an EMG signal which is loaded from a text file. The original signal is shown in the top plot of the attached image. When performing DC offset removal from the raw signal I am getting two lines, one in green and one in blue (second figure). Why is this? How can I keep the green signal only? Below is the code used for removing the DC offset:

EMG_DCoffset_removed = detrend(raw_EMG);
figure(1);
plot(EMG_DCoffset_removed);

Answer 1

[Star Strider]

I cannot duplicate your results with this simulation or with a constant offset:

raw_EMG = rand(1, 1000) + (1:1000)/100;
EMG_DCoffset_removed = detrend(raw_EMG);
figure(1);
plot(EMG_DCoffset_removed);
hold on
plot(raw_EMG)

What did you do to make MATLAB angry at you?