![]() Image: Edge detection (signal and event) example We expect to have the same results for both methods (edge pulse and event). In the following example, we’ll use both the edge detection pulses and events, to sample/update a signal with the values of a sine wave. #Creating falling blocks in mathlab update#We can use edge detection to update the value / state of a signal. In our example we use a Event Scope block to plot the occurrence of the edge detection events.Īs you can see the edge detection events occur in the same time with the edge detection pulses. This can be used to trigger other discrete Xcos blocks. Every time there is a state change in the input signal (rising or falling), the block will output an event. As you can see, the either edge is contains both rising and falling edge detection.Įdge detection can be performed also with the Xcos block Edge trigger. For a better visualization, the Delayblock has the parameter Discretization time step set to 0.1 s, which makes the Boolean edge detection signals to be true for 100 ms. The second plot contains the rising edge detection, the third plot is the falling edge detection and the fourth plot is the either edge detection. The first, upper signal plot is the input square wave. Running the model for 6 s outputs the following graphical window: The shape of the square wave and the outputs of the edge detection subsystems are then plotted in a Scope block, triggered at 0.001 s. #Creating falling blocks in mathlab generator#The output of the signal generator is fed to the signal edge detection functions described above. To test the signal edge detection we are going to use square wave defined with a Pulse Generator block from the Xcos palette. The easiest way to implement an either edge is by performing a logical OR between the rising edge and falling edge detection. Image: Xcos model – either edge detection If any of them occurs, the Boolean output is set to true only during the state transition time step. Image: Xcos model – falling edge detection Either edge detectionĪn either edge detection looks after both rising or falling edges. The only difference is that we check if the current value of the signal is lower than the value it had one time step before. The falling edge detection is done in a similar manner as the rising edge. The RisngEdge_B output signal will be a Boolean pulse signal for the edge detection. If the current value of the signal is bigger than the value it had 1 ms ago, a rising edge had occurred. This means that the output of the Delay block will be delayed with 1 ms. The Delay block has the Discretization time step set to 0.001 s. In the Xcos block diagram above, Sig_Dec represents the input signal, which is changing state. Image: Xcos model – rising edge detection ![]() ![]() In Xcos, for a discrete signal, this transition can be detected by comparing the actual value of the signal u with the previous value u. Rising edge detectionĪ rising edge is the transition of a signal from a low state to a high state. Signal edge detection is useful in for timers, counters or clock resets, for signal state updates or for triggering a set of functions / algorithms. The edge detection is represented by an output Boolean signal, which has the value 1 (true) only during a time step, when the state change has occurred, ![]() The detection of the edge is done on discrete signals. ![]()
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