This example demonstrates how to use a coprocessor-based modulator to generate an SOQPSK modulated signal using NI Data Link Test Framework.

Complete the following steps.
  1. Navigate to <LVAddons>\dltf\1\examples\Data Link Test Framework\Modems\SOQPSK\Host\Modulator and open SOQPSK Modulator.vi.
  2. Use the VST Device Name control to select the VST.
  3. Select the Modem Mode that corresponds with the demodulator that you will be running.
    • Select Continuous for an NI-RFSA-based demodulator.
    • Select Interactive for an RFmx-based demodulator.
  4. Use the Coprocessor Device Name control to select the coprocessor.
  5. Use the Coprocessor Bitfile Path control to select the correct modem bitfile for the selected VST and coprocessor.
    Table 28. SOQPSK Modulator Compatible Bitfiles
    Coprocessor VST Modem Mode Bitfile
    PXIe-6594 PXIe-5840/5841 Interactive soqpsk_modem_dec_dmsc_6594_00.lvbitx
    PXIe-6594 PXIe-5840/5841 Continuous soqpsk_modem_dmsc_6594_00.lvbitx
    PXIe-7903 PXIe-5840/5841 Interactive soqpsk_modem_dec_dmsc_7903_00.lvbitx
    PXIe-7903 PXIe-5840/5841 Continuous soqpsk_modem_dmsc_7903_00.lvbitx
    PXIe-7903 PXIe-5842 Interactive soqpsk_modem_dec_dmsc_7903_01.lvbitx
    PXIe-7903 PXIe-5842 Continuous soqpsk_modem_dmsc_7903_01.lvbitx
    PXIe-7915 PXIe-5840/5841 Continuous soqpsk_modem_dmsc_7915_00.lvbitx
  6. Adjust the Signal Parameters and RF Acquisition Settings to match the settings configured for the corresponding demodulator.
  7. Run the VI.
    • The front panel top-right graph displays a trellis diagram.
    • The front panel bottom-right graph displays the generated spectrum.
    • The string indicator displays the example status.
    • Use the Eb/N0 (db) control to adjust the noise added to the modulated signal on the coprocessor.
    • The Bitfile Redownloaded indicator displays whether the bitfile was downloaded to the coprocessor for the current run of the example.
  8. Stop the example by clicking the Stop button or closing the window.