Custom waveforms are represented as a series of samples—essentially, the samples provide a list of successive values in the waveform. The basic idea is as shown in Fig. 1 below. The sampled points are represented by the black dots in Fig. 1—the only actual information we have is the sampled points: f1, f2, f3, ..., fn. The Arbitrary Waveform Generator (AWG) of the EE board constructs a waveform from these sampled points by assuming that the value of the function is constant between the given points, as shown in Fig. 1.
In order for the AWG to create the waveform corresponding to the provided series of samples, we must tell the AWG the time between successive points (Δt in Fig. 1 above). This information is provided by the AWG at the time the custom signal is generated. The frequency selected at the time the custom waveform is “played” by the AWG sets the number of samples per second at which the points will be played. The general idea is virtually the same as the material that was presented in the background relative to audio files in the Audio and .wav Files project, which is located at the tab to the right. If you feel that a review is necessary at this point, it is recommended that you look through the material associated with that project. However, performing the experiment associated with these fundamental concepts will most likely provide more insight into these topics than any amount of reading.