Acquiring Analog Data and Outputting It with a PC Sound Card
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National Instruments Data Acquisition (DAQ) hardware can be used to acquire many types of signals. Using National Instruments LabVIEW software, these acquired signals can easily be both analyzed and processed using built-in analysis and signal processing VIs. LabVIEW also provides a library of sound VIs, which includes functionality to output analog signals to a PC sound card (Figure 1). Thus, analog signals acquired with DAQ hardware, before or after being processed, can be output to a PC sound card with LabVIEW's sound VIs. Figure 1: LabVIEW Sound VIs This functionality is especially useful when DAQ hardware is being used to acquire an analog signal with frequency components in the audible range (roughly 20 Hz - 20 kHz). Using LabVIEW, the acquired signal can be analyzed. One common analysis technique is to determine the signal's frequency components by applying a Fast Fourier Transform (FFT). Furthermore, to process the signal both a software gain stage and a software bandpass filter can be applied in LabVIEW. The gain stage allows for programmatic control over the signals amplification. With the bandpass filter, a user-defined frequency range is allowed to pass and all other frequency components are filtered from the signal. This processed analog signal can now be output as audio to a PC sound card using LabVIEW's sound VIs. |
Please refer to the Related Links below for a LabVIEW example program that can be used to acquire an analog signal with DAQ hardware, process the signal, and output the processed signal to a PC sound card.
Related Links:
NI-DAQmx: Acquiring Audio and Transferring It to a PC Sound Card
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