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LabVIEW PDM Acquisition Toolkit Help

Last Modified: March 31, 2021

The LabVIEW PDM Acquisition Toolkit helps assess hardware performance of digital audio devices by acquiring and generating pulse-density modulation (PDM) signals.

Understanding PDM Channels and Tasks

Conceptually, a task represents a measurement or generation you want to perform. A PDM input task or PDM output task is a collection of one or more channels with timing, triggering, and/or other properties. Use a PDM input task in your workflow to acquire PDM signals and convert PDM signals to pulse-code modulated (PCM) signals. Use a PDM output task to generate PDM signals.

A bank is a set of PDM input channels with the same timing and trigger settings. All channels in a PDM input task are synchronized.

A PDM data line is a single physical data line, or digital input terminal, that reads data from the left and right microphones, or channels. Therefore, one data line can read two channels. The left channel is associated with a rising clock edge. The right channel is associated with a falling clock edge.

Refer to the PDM Acquisition Toolkit Specifications for the supported number of PDM channels and data lines and for the layout of banks to channels.

The PDM Acquisition Toolkit supports multiple concurrent tasks with the following limitations:

  • The same channel cannot be in more than one task at the same time.
  • PDM channels from the same bank cannot be in different tasks at the same time.
  • The number of concurrent PDM input tasks is limited to the number of timing engines supported.
  • The same hardware device cannot support both a PDM input task and a PDM output task at the same time.


Refer to the labview\examples\PDM Acquisition Toolkit directory for examples of using the PDM Acquisition VIs.

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