Implement the circuit defined below with NAND SR latch.
An asynchronous sequential circuit has two internal states and one output. The excitation and output functions describing the circuit are as follows.
$Y _1 = x _1x _2 + x _1y _2’ + x _2’y _1$
$Y _2 = x _2 + x _1y _1’y _2 + x _1’y _1$
$z = x _2 + y _1$
