What is baudline?
Mystery Signal
The waveform display is a sample amplitude vs. time view into the data.  This is similar to the traditional oscilloscope display.  When baudline is in the record or play modes the waveform displayed is the real-time data that is currently being input or output.  When baudline is in the pause mode the waveform displayed here is linked to the spectral slice cursor in the main spectrogram window.

To open the waveform window select the waveform option in the displays sub section of the main window. 

Click the thumbnail below for a larger image.

The popup menu on the right is accessed by holding down the third mouse button while in the waveform window.  Through this menu windowing channel enabling, timebase scaling, amplitude scaling, and opening the zoom control can be performed.

Enable or disable the windowing overlay.  The orange hump shaped overlay is the spectral windowing region.  It is overlaid on top of the samples that are currently transformed into frequency space and displayed in the spectrum window.  This also happens to match the data of the slice cursor in the spectrogram window.  Think of this as a big wide cursor that shows exactly what is being imported to the spectrum window.

This selects which channels should be enabled for viewing.  The default is to view all channels.  Note the channels need to be mapped and they need to be enabled in this menu before anything is displayed.  The intended use of this menu is to reduce the number of displayed waveform channels for aesthetic or duplicate reasons.

timebase scaling
With the menu shown above the horizontal timebase axis can be zoomed in or out.  You may find tearing off this menu or using the Alt+arrow shortcuts faster and more convenient.  See the keyboard reference tables for all of the hotkey shortcuts. 

amplitude scaling
This is a zoom factor into the vertical axis of the waveform amplitude axis.  Zoom all the way in (Alt+Up) to 8192X to see small details or zoom all the way out (Alt+Down) to 1X to see the full native amplitude range.

zoom control
Open the zoom control window.

title bar
Like the spectro window's title bar, this title bar contains a lot of useful state information about the waveform window, such as F# key bank selected and status, amplitude and timebase zoom factors, and file name if any.

The horizontal axis on the top ruler is time in milliseconds (ms); note that depending on the zoom level the units can switch to seconds (s).  The vertical axis on the left ruler is in dBm which ranges from +90 dBm, the maximum sample amplitude in 16 bit linear coding space, to -90 dBm, the most negative sample amplitude.  Note that 0 dBm is the origin and it represents the smallest sample amplitude which is the same as digital silence.

This is sample amplitude vs. time with either the newest recorded data or the end of the file being the rightmost.  Stereo or multiple channels will be overlaid or they will be in separate rows depending on the position in the input channel mapping window.  See the purple-green stereo example waveform below:

cursor bar
There are two different possible cursors in the waveform window.  In the pause mode a light gray vertical line tracks the selector bar in the spectrogram window.  The offset of this line is a function of the windowing overlay shape.  Its movement follows the mouse, and it represents the true position within the waveform file.  Press and hold the second mouse button to pop up the crosshairs (see above picture).  The crosshairs are useful for making accurate time-amplitude measurements.

The on-screen display shows the time, dBm, and hexadecimal sample value that the mouse is currently pointing to.

scroll bars
The time history scroll bar is on the bottom and amplitude scroll bar is on the right.  They allow moving the viewport around in the waveform domain. Note that the mouse scroll wheel is attached to the amplitude scroll bar, Alt+wheel zooms the vertical amplitude axis, and the Shift+Alt+wheel switches control to zoom the horizontal time axis.  The arrow keys navigate and the Alt+arrow keys zoom as would be expected.  The home, end, page up and down, like with the spectrogram window, navigate the time axis.  See the keyboard reference tables for all of the hotkey shortcuts. 

delta duration measurements
Click and drag the cursor bar to select a section of sample data.  A delta duration appears as a "heads up" display next to the mouse pointer.  When the mouse button is released the selection remains but the delta duration disappears.  The delta duration is simply the absolute value of the difference of the start position from the end selection position.  It can be used as an accurate method to measure time intervals.  The selected data can then be saved or pasted into a number of other windows for processing and analysis.

periodic helper bars
In the screenshot above, the vertical lines are the periodic helper bars.  They are useful for determining the exactness of any repeating or periodic behavior.  They can be used for making precise delta timing measurements.  They can also be used to create a sort of user adjustable grid for the time domain.  Here are the steps on how to use them:
  1. Press and hold the 2nd mouse button which will pop up the cursor crosshairs. 
  2. Move the mouse in the waveform display and align the time axis slice cursor to a point of interest.
  3. Press and release the Shift key.  This will flip the orientation of the crosshairs bars transforming them into the periodicity helper bars.  This action will also anchor the initial position (0 ms).
  4. Move the mouse and the periodicity bars will appear and move appropriately.  The spacing of the entire grid changes.  Rough measurements can be made quickly. 
  5. Hit the left or right arrow keys to perform fine tune adjusting of the delta periodicity.  Sub sample resolution can be achieved this way.
  6. Release the 2nd mouse button to make the lines disappear.  Or press the Shift key to toggle back to the crosshair behavior (goto step 1).  Move the mouse, adjust the time anchor point, and hit Shift again.  ....
The periodicity bars are also automatically mirrored in the Spectrogram window in a dual tracking manner.

Copyright © 2005 - group - blog - site map