Menus
File SubMenu
This submenu provides access to the file operation and printing functions.
New (File SubMenu) (ALT-F-N, CTRL-N)
The command is used to create a new, blank document for measurement, with the system default panel setting fixed in the factory. The new document will be used to hold the latest collected frame of data.
This command is also available through the button  in the Instrument Toolbar. When there is no Oscilloscope, Spectrum Analyzer and Multimeter opened, click the above "Oscilloscope" button will open a new document without changing the current Trigger and Sampling Parameters.
Open (File SubMenu) (ALT-F-O, CTRL-O)
The command is used to open an existing document. Only standard and extensible WAV files in PCM format can be opened. An error message will pop up if the file format is not recognizable. WAV files with PCM format are widely supported by many softwares. You can use a third-party software such as "Sound Recorder" provided in Windows to record the data and then use Multi-Instrument to display and analyze the data.
This command is also available through the button  in the Sampling Parameter Toolbar. Only one document can be opened at a time.
If the file to be opened is too big to be held in one oscilloscope frame, the software will automatically open the file frame by frame (see description below).
Open Frame by Frame (File SubMenu) (ALT-F-F)
The command is the same as the Open command described previously, except that it opens a WAV file frame by frame. Therefore it is particularly useful for opening a long WAV file. The frame size (i.e. Record Length Per Scan) should be set first before executing this command. For example (see figure below), if the Record Length Per Scan is 441 and the WAV file has 44100 points, then the file will be split into 100 frames with each frame contains 441 points. Under this mode, the Long Wave File Navigation Toolbar becomes visible. The meaning of each component in this toolbar is listed as follows:
 : Frame Up, if pressed, the current frame position will move one frame backward if the beginning of the file has not been reached yet.
 : Frame Down, if pressed, the current frame position will move one frame forward if the end of the file has not been reached yet.
 : Frame Auto Scroll, a toggle button, if pressed down, the current frame position will move forward frame by frame with or without overlap automatically till the end of the file is reached. Every frame will be analyzed and displayed according to the current settings, and no frame will be skipped. This feature is very useful for performing post-analysis such as Spectrum 3D Plot and Data Logging autmatically on a long WAV file. During the auto scrolling process, the Frame Up and Frame Down buttons are disabled. If the Frame Auto Scroll button is released up, the auto scrolling process will stop, and the Page Up and Page Down buttons will be enabled again.
 : Current Frame Position slider. It reflects the position of the current frame with regards to the length of the file. It can also be used to adjust the position of the current frame.
 : Current Frame Position/Length of the File. For example, 0.08s/1s means that the current frame starts at 0.08 second and the length of the file is 1 second.
 : Frame Overlap Percentage. This parameter specifies the inter-frame overlap percentage and has effect on Frame Down, Frame Up, Frame Auto Scroll commands. Options available are: 0%, 25%, 50%, 75%. As a comparison, the Window Overlap Percentage in the Spectrum Analyzer View Toolbar specifies the intra-frame overlap percentage. You can combine the two overlap percentages to achieve a certain overall overlap scheme for FFT analysis.
Import (File SubMenu) (ALT-F-I)
This command is used to import data from a properly formatted TXT file. The following illustrates the format of the TXT file for single channel and dual-channel cases.
(1) Format for Single Channel:
Example:
- Sampling Frequency (Hz) = 44100
- Sampling Bit Resolution (Bits) = 16
- Sampling Channels = 1
- A:Full-scale Voltage (V) = 1
- A:Sensor Sensitivity (mV/V) = 1000
- Total Data Points = 441
1,0
2,0.141968
3,0.281097
......
439,-0.41449
440,-0.281097
441,-0.141968
(2) Format for Dual Channels:
Example:
- Sampling Frequency (Hz) = 44100
- Sampling Bit Resolution (Bits) = 16
- Sampling Channels = 2
- A:Full-scale Voltage (V) = 1
- A:Sensor Sensitivity (mV/V) = 1000
- B:Full-scale Voltage (V) = 1
- B:Sensor Sensitivity (mV/V) = 1000
- Total Data Points = 441
1,0,0
2,0.141968,-0.141968
3,0.281097,-0.281097
......
439,-0.41449,0.41449
440,-0.281097,0.281097
441,-0.141968,0.141968
The first a few lines (start with “;”) form the header, the values on the right hand side of “=” are important, they specify the Sampling Frequency (Hz), Sampling Bit Resolution (Bits), Number of Sampling Channels, Full-scale Voltage (V), Sensor Sensitivity (mV/V), and Total Number of Data Points.
The header lines are followed by the data lines. Each data line contains two (single channel) or three (dual channels) comma separated variables. The first variable is the sequential number, and the second and third variables are the data for Channel A and Channel B respectively. The absolute values of all the data must be lower than the Full-scale Voltage specified in the header lines.
In addition to the standard format described above, the TXT files exported by the Oscilloscope and the Signal Generator, which have a slightly different format than the above one, can also be imported for analysis.
Some sample files are provided in the WAV directory of the software and can be used as templates.
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