In this unit we will learn to set up the global properties for a time domain simulation in
We access the global properties by selecting the Root Element in the Element Tree.
We have already seen that the sampling rates of both optical and electrical sources are
inherited from the root element by default.
The exception is the ONA where the sample rate is defined locally by default using the
"frequency range" parameter.
To understand the various simulation properties available and how they are related, let's
take a look at an example.
In this example, the time window is set to 1.6 ns.
The bit rate is set 1e10 bit/s, so the sequence length is 16 bits, as it's calculated as the
time window times the bitrate.
The sample rate is set to 6.4e11 so the number of samples is 1024, as it's calculated as
the time window times the sample rate.
Note that one over the sample rate is the sample period, which is the time between samples.
Special care must be taken when setting the sample rate, particularly for Transient Sample
We'll provide tips and tricks for setting the sample rate in the Sample Rate unit of
the Transient Sample Mode simulation setup tips subsection.
The equations shown here describe the relationships between the different simulation properties.
You can review them by following the link to the KB page provided below the video.
Given these relationships, the signal sampling can be fully described by only a subset of
The "simulation input" property of the Root Element can be used to switch between which
subset of properties are active.
The options are "sequence length", "time window" and "sample rate".
Refer to the same KB page below the video for more details about these options.