Kurzweil K2000 - MUSICIANS GUIDE Musician's Manual page 354

FUNS
The FUN Equations
warp4(a, b)
This equation, the Period Inverter,Ô is based on repeated evaluations of the value of input b.
The K2vx compares each new value of input b with the value from the previous evaluation. If
the absolute value (always a positive number) of the difference between the two is greater than
the value of input a, the current value of input b is multiplied by -1.
The primary feature of this equation is that it will take a discontinuous signal and make it
continuous. If, for example, FUN1 uses an equation like a(y + b), its output can wrap around
from +1 to -1, or vice versa. You could set FUN1 as input b for FUN2, set input a of FUN2 to
ON (+1), and FUN2 would remove the discontinuity from the signal. The Þrst graph below
shows a hypothetical output signal with such a discontinuity, and the second shows how FUN2
in this case would make the signal continuous without drastically changing its shape.
If, on the other hand you want the signal to become discontinuous, you can use the warp4(a, b)
equation in a single FUN, with input a set to OFF (0), and the signal would be multiplied by -1
with each evaluation of input b.
-1
warp8(a, b)
This relatively simple equation is a x b x 8. If the result is beyond the range of -1 to +1, it wraps
around from +1 to -1 (or vice versa), until itÕs within the allowable range. The table below
shows some examples of how this works.
a x b x 8 =
-7.4
-4.2
-1.8
a AND b
The values of inputs a and b are interpreted as logical quantitiesÑtheyÕre considered TRUE if
theyÕre greater than +.5, and FALSE otherwise. This turns the FUN into an on/off switch. In the
16-12
output
values
+1
input
1
values
-1
discontinuous
input b signal
Þnal output value
-.6
.4
1.2
2.6
5.4
output
values
+1
-1
-1
same input b signal
with input a = 1
.4
-.2
.8
-.6
.4
-.2
.6
-.4
input
1
values