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Opening and Saving Wave Files
Clicking one of the><New/Open/Save/Save As> menu items or clicking the corresponding toolbar button will activate the Wave File Management dialog box. This allows you to open, save or close up to 16 individual mono wave files. Stereo wave files can be opened and you will be asked which channel to analyze; however, recording will be disabled for that channel. Only the .WAV format is currently supported, however you may import raw data files from other acquisition systems using the File Import command.
Enable Recording - this option is only available in the Recorder Mode and controls whether or not the analyzer will record data from that specific channel or not. If no wave file is open the analyzer will record to an Untitled file. After recording the data you can either save the file or close it without saving.
When recording to a preexisting wave flie the sampling rate of the hardware must match the sampling rate of the wave file. This is because the .WAV file format requires a constant sampling rate throughout the entire file. The Post Processing mode allows you to process files that have different sampling rates.
When the mode is changed to Real-Time, the current files will be closed and you will be prompted to save it if necessary.
Save All Files Using a Prefix
Working with large numbers of files can be cumbersome. This feature allows you to specify a "Prefix" to be used as a pattern to quickly save all open files. The channel number will be appended to the Prefix - for example a prefix of "Project 451" will save files with names as follows:
Project 451_Ch_0.wav
Project 451_Ch_1.wav
Project 451_Ch_2.wav
Project 451_Ch_3.wav
etc...
The Channel Name* can also be included in the filename when using a prefix. Here are some examples:
Project 451_Accel_X_Ch_0.wav
Project 451_Accel_Y_Ch_1.wav
Project 451_Accel_Z_Ch_2.wav
Project 451_Mic_H2_Ch_3.wav
etc...
*The channel name is what is shown in the Calibration tab of the processing settings
Wave File Groups
You can Save and Load groups of wave files using the corresponding buttons on the bottom of the dialog box. This creates a small text file (.wfg extension) containing a list of open wave filenames for each channel. It is stored in the same folder as the wave files. This is helpful for recording and post processing large sets of wave files.
File Storage Requirements
The amount of memory required for each minute of data varies widely depending upon the sampling rate and sampling format. Some typical values for mono recording are shown below:
Sampling Rate (Hz) Sampling Precision (bits) Bytes/Minute
11,025 8 661,500
11,025 16 1,323,000
22,050 8 1,323,000
22,050 16 2,646,000
44,100 8 2,646,000
44,100 16 5,292,000
44,100 24 7,938,000
96,000 16 11,520,000
96,000 24 17,280,000
Continuous Recording Capability
Wave files can store up to 2 GB of data in a single file (the corresponding time depends upon the sampling format). When this limit is reached, the program will momentarily stop recording, save the file and then start recording again in a new file. If the file is does not yet have a name, the program will give it a name using the computer date and time. The file will be stored in the \wave folder as specified in the <File><Set Paths> dialog. This feature applies to the hard disk recording mode only.
Example: c:\speclab\wave\recording_2010_11_26_102011.wav
(in this example the date and time were 10:20:11 Nov, 26 2010 when the file was saved)
See also: Recorder Mode , Importing Files, Exporting Files, Cut/Copy/Paste commands