User guide

12-2
Delays and Timing
Transport and Inertial Delays
Delays can be categorized into transport and inertial delays.
Transport delays allow all pulses that are narrower than the delay to
propagate through. For example, Figure 12-1 shows the waveforms
for an input and output port of a module that models a buffer with a
module path delay of seven time units between these ports. The
waveform on top is that of the input port and the waveform underneath
is that of the output port. In this example you have enabled transport
delays for module path delays and specified that a pulse three time
units wide can propagate through (how this is done is explained in
"Enabling Transport Delays" on page 12-7 and "Pulse Control" on
page 12-7).
Figure 12-1 Transport Delay Waveforms
At time 0 a pulse three time units wide begins on the input port. This
pulse is narrower than the module path delay of seven time units, but
this pulse propagates through the module and appears on the output
port after seven time units. Similarly another narrow pulse begins on
the input port at time 3 and it also appears on the output port seven
time units later.