This example demonstrates how to use a coprocessor-based demodulator to demodulate an SOQPSK modulated signal while enabling the use of InstrumentStudio using RFmx and NI Data Link Test Framework.

Complete the following steps.
  1. Navigate to <LVAddons>\dltf\1\examples\Data Link Test Framework\Modems\SOQPSK\Host\RFmx Demodulator and open SOQPSK RFmx Demodulator.vi.
  2. Use the VST Device Name control to select the VST.
    Note If using the same VST as a modulator and a demodulator, you must set the Modem Mode control to Interactive in the corresponding modulator example.
  3. Use the Coprocessor Device Name control to select the coprocessor.
  4. Use the Coprocessor Bitfile Path control to select the correct modem bitfile for the selected VST and coprocessor.
    Table 30. SOQPSK RFmx Demodulator Compatible Bitfiles
    Coprocessor VST Bitfile
    PXIe-6594 PXIe-5840/5841 soqpsk_modem_dec_dmsc_6594_00.lvbitx
    PXIe-7903 PXIe-5840/5841 soqpsk_modem_dec_dmsc_7903_00.lvbitx
    PXIe-7903 PXIe-5842 soqpsk_modem_dec_dmsc_7903_01.lvbitx
  5. Adjust the Signal Parameters and RF Acquisition Settings to match the settings configured for the corresponding modulator.
  6. Run the VI.
    • The front panel graph displays the constellation.
    • The Bit Error Rate indicator displays the calculated bit error rate. Click the Reset BER button to reset the calculation.
    • Click the Interactive Mode button to enable and disable status checks of the RFmx session in the example:
      • Use Local Control when the RFmx session is used in the example.
      • Use InstrumentStudio Control when the RFmx session is active in the InstrumentStudio UI.
    • The string indicator displays the example status.
    • The Bitfile Redownloaded indicator displays whether the bitfile was downloaded to the coprocessor for the current run of the example.
  7. Stop the example by clicking the Stop button or closing the window.