You can generate stimulus data and acquire the response data for analysis by synchronizing the generation and acquisition sessions.

To perform software comparison, you must transfer all data to the host computer for post-processing, which makes this method suitable for slower-speed applications. Transferring all data to the host might exceed bandwidth if the acquired data exceeds the tester’s onboard memory. For this situation and other cases that require faster comparison rates, real-time hardware comparison might be used.
Note Real-time hardware comparison (HWC) is supported only on NI 6547/6548/655x devices.
You can compare expected response data with actual response data in the following ways:
  • Response-only mode—The device does not drive any data, it only acquires and compares. A generation session downloads the expected waveform. In the stimulus-response mode, the device drives and compares data in the same session. You can download waveforms with drive and/or compare data. All digital states are supported in this mode.
  • Stimulus-response mode—The NI 6547/6548/655x device drives and compares data in the same operation. You can download waveforms with drive and/or compare data. This mode supports all digital states, which means that the waveform contains both generation and expected data.

    • The following figure shows the flow of the stimulus-response mode: