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Basic Operations
The program acquires data from a Data Translation DT-9800 multichannel industrial data acquisition USB hardware module and performs FFT based signal processing operations and displays the results.
The program has three distinct operating Modes and five separate Plots.
Modes
Real-Time mode takes the signal directly off of the DT-9800 module, processes it and displays the results. You can run for an indefinite period of time but the last 60 seconds (user adjustable) will be buffered. If you stop the analyzer and change to the Recorder or Post Processing mode you will be given a chance to save this data buffer to a wave file.
Recorder mode allows you to save the raw digitized signal to your hard disk in the form of a .WAV file. You can also playback the signal through the DT-9800 D/A channel or through your sound card output channel. To begin playback you must first select the time segment to play by clicking the selection arrow on the time series polot and then clicking and dragging across the data segment. Pressing the "Play" button (speaker icon on the plot toolbar) will begin playback. Only one channel can be played back at a time.
Post-Processing mode allows you to process data which was previously recorded and stored on disk in a .WAV file. This mode allows greater flexibility than the Recorder or Real-Time modes in the analysis process. In particular, this mode allows the use of overlap processing to effectively stretch the time resolution in both the Spectrogram and 3-D Surface plots.
Plots
The Time Series plot shows the digitized waveform. It is similar to an oscilloscope display (amplitude versus time).
The Spectrum plot displays the amplitude of the signal versus frequency.
The Phase plot displays the phase of the signal versus frequency.
The Spectrogram plot displays the spectra over time. The amplitude is shown in color or grayscale.
The 3-D Surface plot displays a perspective of the spectra over time.
See also: Setting up the Analyzer