**Block Inputs:** Two scalar inputs.

The greater than or equal to (>=) block produces an
output signal of 1 if and only if input signal *x*_{1} is greater
than or equal to input signal *x*_{2}. Otherwise, the output is 0.
On the connectors, “l” represents *x*_{1} and “r” represents
*x*_{2}.

If you right-click the >= block, the Boolean block menu appears allowing you to assign a different function to the block.

**1. Simple
if-then-else construct**

Consider a variable *y* such that:

If* x* ≥ 0.5 then *y* = sin(*t*); else y =
1

where *t *is simulation time. Let *x* be a unit
step delayed by 3s. This is usually represented as *u*(*t *- 3). This
system can be realized as shown below.

Until the onset of the step input at *t* =
3s, the Boolean inequality *x* ≥ 0.5 evaluates to false
and *y* takes on a value of 1. At *t* = 3s, the Boolean inequality
evaluates to true and remains true for the duration of the simulation duration.
Consequently, from this point onwards, *y* takes on the value of
sin(*t*).