Arbitrary Function Generators (AFGs) are widely used
by researchers, design engineers and test engineers to
simulate their devices under test (DUTs). Today’s electronic
designs are getting more and more complicated, which is
leading users to demand that their AFGs offer a richer set of
features, higher signal delity, greater exibility and superior
ease of use.
AFG31000 Series Arbitrary Function Generators offer
a choice of waveform generation modes—Basic and
Advanced—to accommodate a range of use cases to ensure
the best test results and user experience.
Figure 1. The AFG31000 Series home page.
Basic mode
In Basic mode, an AFG31000 works much like a traditional
AFG, based on the Direct Digital Synthesis (DDS) technique.
Although some might argue that DDS is an “out-of-date”
technology with some weaknesses, it is still fundamental to
almost all of the AFGs in the market today, and has a lot of
advantages over the newer technologies.
Figure 2. User interface of a dual-channel AFG31000 in Basic mode
Frequency agility
Figure 3. The simplied architecture of a DDS-based AFG
The following is fundamental to all digitized generators:
Output Frequency = Sample rate ÷ number of samples in one
cycle (equation 1)
For DDS-based AFGs, the sample rate is xed; when the
user changes the output frequency, the number of samples
in each cycle changes accordingly. The phase accumulator
does this automatically by repeating or skipping points in the
waveform memory.
2 | WWW.TEK.COM
Differentiating between Basic and Advanced Modes for
AFG31000 Series Arbitrary Function Generators
APPLICATION NOTE