DDS Stream - 2022.1 English - UG1483

Library

AI Engine/DSP/Stream IO

Description

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

Parameters

Main

Output Data Type:

• Describes the type of individual data samples output of the DDS function. It should be cint16 or cfloat.

Output Frame Size (Number of Samples):

• Specifies the number of samples in the output frame. The value must be in the range 8 to 1024 and the default value is 32.

Number of Parallel Outputs (SSR):

• This parameter specifies the number of output ports and must be of the form 2^N, where N is a non-negative integer.

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 where:
  • Fo = Output frequency.
  • N = 32, which represents the accumulator width, and it is fixed.
  • Fs = Sampling frequency.

Initial Phase Offset:

• Specifies the initial phase offset. The default value is 0.

Sample Time:

• Specifies the sample time for the block output port. The default value is -1.

Advanced

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.