The post-processing mode allows you to analyze a previously recorded WAV file. The priority is given to spectral updates and the data is not played back through the speakers. For playback, use the recorder mode, or the Play/Play special commands.
This mode provides greater control over the processing than the Recorder or Real-Time modes. There will be no gaps in the processed data, and you can "stretch" the time axis on the Spectrogram and 3-D Surface Plots by performing overlap processing . In addition you can edit and playback selected time segments which allows in-depth analysis not possible in the real-time mode.
When a .WAV file is opened, the sampling rate and format are changed to match the rate at which the file was recorded - the Sampling Rate must remain constant within a single .WAV file. The current sampling rate is always displayed in the status bar along the bottom of the application.
Single step operation:
Pressing the <Enter> key or (+) will perform a single FFT measurement and then automatically stop the analyzer (single step measurement). The current average is not reset during single step operations.
Pressing the minus key (-) will cause the analyzer to step backwards in the file. The step size used corresponds to the current overlap percent setting.
Time Series plot must have the "focus" for these special keystrokes to function.
See also: Basic Operation , Overlap Percentage, Performance Issues , Working with Audio Files