Standard function output mode is used to generate standard function waveforms, including sine, square, and triangle.

Direct Digital Synthesis

The standard function output mode is implemented through direct digital synthesis (DDS) on the PXIe-5413.

Figure 4. DDS-Based Waveform Generation Block Diagram


You can use the lookup memory in standard function output mode only. You can store one cycle of a repetitive waveform—a sine, triangular, square, or arbitrary wave—in the lookup memory. Then, you can change the frequency of that waveform by sending just one instruction. You can use standard function output mode for very fine frequency resolution function generation. Because standard function output mode uses an accumulator, waveform generation loops back to the beginning of the lookup memory after passing through the end of the lookup memory.

In standard function output mode, each stage is made up of two instructions: the frequency and the time.
  • Frequency instruction—Specifies the frequency of the waveform generation.
  • Time instruction—Specifies the duration when the frequency is generated.
    • Note You cannot specify the number of iterations for a waveform to generate in Standard Function output mode.