www.gusucode.com > dsp 案例源码程序 matlab代码 > dsp/DetermineTheNumberOfZeroCrossingsExample.m

    %% Determine The Number of Zero Crossings
%%
% *Note*: This example runs only in R2016b or later. If you are using an
% earlier release, replace each call to the function with the equivalent
% |step| syntax. For example, myObject(x) becomes step(myObject,x).

%% 
% Find number of zero crossings in electrocardiogram data.
EcgData = ecg(500)';
Hzerocross = dsp.ZeroCrossingDetector;
NumZeroCross = Hzerocross(EcgData);  % Equal to 4
plot(1:500,EcgData,'b',[0 500],[0 0],'r','linewidth',2);