Daqarta for DOS Contents
BOARD and VIRTUAL SOURCE CONTROL:
BOARD / VIRTUAL SOURCE TOGGLE (Board):The Board key (unshifted B-key) selects the data acquisition board, if installed, as the signal source for Daqarta. When off (the power-up default), the Virtual Source is active.
The Virtual Source allows you to experiment with most of the features of Daqarta without having a data acquisition board installed. Even if you do have a board, the Virtual Source can provide complex input signals that you might not have available, like FM and AM modulation. The Sine source is distortion-free, and noise levels can be controlled.
In addition, you can control the number of bits of resolution of this "board". This can help with purchase decisions, since 12-bit boards are often faster and/or less expensive than 16-bit boards. Do you really need 16-bit resolution? You can also learn about the interactions between noise levels, bits of resolution, and averaging... the "dither" story.
When a board (with the appropriate driver in DQA.CFG) is present, Daqarta observes the sample rate limitations of the board, even when in Virtual Source mode. If you want to experiment with a "faster" board, you can omit the board driver and run only with Virtual Source. You can then set any (simulated) sample rate you want, from femtoHertz to TeraHertz and beyond.
BOARD CONTROL MENU:Hit CTRL-B to bring up the control menu for either the data acquisition Board or the Virtual Source, depending upon which is currently active from the last B-key toggle.
Each data acquisition board driver has its own Help text, which is available via the Control Help system. Use ALT-H to see a list of all the installed plug-in modules, of which the board will always be the second entry. Hit ENTER to bring up a single-page summary of switch and parameter settings. Another hit of the ENTER key will bring up the complete Control Help system for the board, if present.
Full board-specific Control Help systems are included for all board drivers supplied with Daqarta, but even user-written drivers should at least have the single-page summary.
Boards, like all plug-in modules, may support parameters on the DQA.CFG line that loads them. These may be used to tell the module about hardware switch settings that it can't test directly, or about preferences like which DMA channel or Interrupt Request (IRQ) line to use. Some boards may have versions that differ only in maximum sample rate, and this may be supplied as a parameter.
In general, each board menu allows you to select the active Channel, the sensitivity Range, and any relevant digital I/O port bits for use as External Trigger, Average Remote Control, or DDisk Remote Control inputs, and Trigger Pulse outputs. Some board menus may not have all of these, and some may have additional features, depending on the capabilities of the board.
Boards with a lot of other capabilities may have multiple menu pages, accessible via CTRL-PgUp and CTRL-PgDn.
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