Function Generators allow you to generate periodic standard functions such as sine, square, triangle, ramp up/down, DC, and noise.
If the function generator has Direct Digital Synthesis (DDS), a single period of the standard waveform is loaded from a look-up table, and the device chooses samples from memory to achieve the periodic signal at precise frequencies instead of generating all samples of the waveform. Because of this, a DDS capable card can achieve very precise frequencies and can create a phase-continuous signal with frequency hopping.
The Configure Standard Waveform.vi
is used to select which type of standard waveform is going to be generated.
- Arbitrary Function Generator
Arbitrary Function Generators refer to function generators that can generate a periodic, user-defined waveform which typically consists of exactly 16,348 points using DDS.
This waveform can be defined by selecting User as the Standard Waveform and uploaded to memory using the Define User Standard Waveform.vi
Because this waveform is defined as a Standard Waveform, Arbitrary Function Generator should still be configured with the Standard Function output mode when using the Configure Output Mode.vi
- Arbitrary Waveform Generator
Arbitrary Waveform Generators allow you to generate a user-defined waveform of any size, unlike an Arbitrary Function Generator which can only generate a custom periodic waveform.
AWGs operating in Arbitrary Waveform mode only generate each sample of the waveform that is stored in memory in order. While AWGs allow a user to precisely define the waveform to generate in arbitrary waveform mode, they are limited in the frequency precision they can achieve, particularly at high frequencies. Discontinuities may also occur if the frequency or the waveform is modified on the fly.