Edwin Jan Klein - Universiteit Twente

87
Simulation and analysis
If the primitive represents a time propagating construct then a time delay has to be
taken into account between the instant that a signal enters one of the inputs Ii and the
moment when the results of the calculation can be forwarded to the next primitive.
Instead of calling the calculation function of the next primitive directly this call is
therefore redirected through a scheduler as shown in Figure 4.11. This scheduler will
then ensure that at the correct time the result data belonging to output O1 is placed on
the port connected to this output. After this the process is finalized by once again
calling the calculation function of the parent of this port.
Primitive
I1
Im
O1, dT,
Port#
Primitive
F ( x .. xn
, I1..
I
1 m
Figure 4.11. A Primitive with delayed (through the scheduler) result forwarding.
The pseudo code implementation of a waveguide, being a typical example of a time
propagating element, is given in Listing 4.3. The time propagating section of the
calculation is code written out in bold and is largely dedicated to gathering all the data
required to build a “call” for the scheduler. As was the case for the coupler the
waveguide also uses a split calculation for each direction of the signal through the
waveguide (entering n1 or n2).
)
Scheduler
t
t+ dT
O1
Primitive