Table Of Contents

DDS (Multirate Dataflow)

Last Modified: September 10, 2016

Generates sine and cosine waveforms with configurable phase increment and offset.

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phase increment

Normalized increment value with the range [-0.5, 0.5), which corresponds to +/- half of the sinusoid period. The DDS node advances the waveform phase by this amount for each corresponding output value.

This input appears only if you disable the Constant option on the Configure DDS dialog box. On the host, the default data type of this input is double-precision floating-point.

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sine

Sine waveform with range [-1.0, 1.0].

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cosine

Cosine waveform with range [-1.0, 1.0].

DDS Configuration

You can configure the DDS in terms of units, such as Hertz or radians, or via normalized ranges. The node calculates configuration options and ranges displayed in Hertz on the Configure DDS dialog box with the assumption that you interpret the resulting waveforms as if they were sampled at the Design Clock Rate. You can use these calculations for modeling frequency characteristics of waveforms. However, the DDS node might execute at a different rate than the Design Clock Rate.

The Fixed Point Resolution section of the Configure DDS dialog box applies only when you use a fixed-point implementation. The ratio of (Design Clock Rate/Frequency Resolution) determines the fixed-point precision of Phase Increment.

Where This Node Can Run:

Desktop OS: Windows

FPGA: All devices


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