FUNS
The FUN Equations
16-14 
a(y + b)
The values of y and b are added, then multiplied by the value of a.
ay + b
The values of a and y are multiplied, then added to the value of b.
(a + 1)y + b
1 is added to the value of a. The sum is multiplied by the value of y. The result is added to the 
value of b.
y +a(y + b)
The values of y and b are added. The sum is multiplied by the value of a. The result is added to 
the value of y.
a |y| + b
The absolute value of y is taken (if itÕs a negative value, itÕs multiplied by -1). The absolute 
value of y is multiplied by the value of a. the result is added to the value of b.
Sample b On a
This is a sample and hold function. The values of inputs a and b are interpreted as logical 
quantities, as described for the equations a AND b, a OR b. When the value of input a changes 
from FALSE to TRUE (goes above +.5), the value of input b at that moment is sampled 
(recorded), and becomes the FUNÕs output value. This value remains constant until input a 
makes another transition from FALSE to TRUE.
Sample b On ~a
This works like the previous equation, but the value of input b is sampled whenever the value 
of input a makes a transition from TRUE to FALSE.
Track b While a
This equation also interprets the values of inputs a and b as logical quantities. While the value 
of input a is TRUE, the value of input b is used as the FUNÕs output value. The output value 
changes exactly as the value of input b changes. When the value of input a goes FALSE, the 
FUNÕs output value freezes and remains constant until the value of input a becomes TRUE 
again. The FUNÕs output value then continues to track the value of input b.
Track b While ~a
This is the opposite of the previous equation. The FUNÕs output value tracks the value of input 
b as long as the value of input a is FALSE.
Diode Equations
The remaining equations perform a diode-like function; only positive input values are 
signiÞcant. If the result of the equation is negative, the FUNÕs output value is 0. You can use 
these equations to limit bipolar control signals to unipolar values. Normally youÕll use these by 
setting input a or b to ON or OFF, and assigning some control source to the other input. These 
will enable you to produce a variety of output curves.