double_thresh

Function for a simple hysteretic Schmidt trigger on a vector

Description

This function performs a Schmidt trigger operation on a vector. A Schmidt trigger is a hysteretic thresholding operation, where the state of the trigger will stay low until the signal data crosses above the upperthreshold, then will stay high until it falls below the lowerthreshold.

%example code illustrates how to use the trigger and its benefit over a simple threshold.
signal=sin((0:.01:2*pi));
signal=signal+.2*rand(size(signal));
simplestate=signal>0;
state=double_thresh(signal,.1,-.1);
figure;
hold on;
plot(signal);
plot(simplestate,'g');
plot(state,'r');

• MATLAB release: MATLAB 7.4 (R2007a)