DDS - 2022.1 English

Vitis Model Composer User Guide (UG1483)

Document ID
Release Date
2022.1 English


AI Engine/DSP/Window IO


This block implements the Direct Digital Synthesizer (DDS) targeted for AI Engines.


Output data type
Describes the type of individual data samples output of the DDS function. It should only be cint16.
Output window size (Number of samples)
Specifies the number of samples in output window. The value must be in the range 8 to 1024 and the default value is 32.
Phase increment
Specifies the phase increment between samples. The value must be in the range 0 to 2^31 and the default value is 0. Input value 2^31 corresponds to Pi (i.e., 180).

Phase increment is calculated using the formula (Fo*(2^N)) / Fs

  • Fo = Output frequency
  • N = 32, which represents the accumulator width, and it is fixed
  • Fs = Sampling frequency
Sample time
Specifies the sample time for the block output port. The default value is -1.
Target output throughput (MSPS)
Specifies the output sampling rate of the DDS function in Mega Samples per Second (MSPS). The value must be in the range 1 to 1000 and the default value is 200.