Daqarta for DOS Contents



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Daqarta for DOS
Data AcQuisition And Real-Time Analysis
Shareware for Legacy Systems

From the Daqarta for DOS Help system:


     | mV  TRIG  Title  Count  Speed .------.|
     | .---------------------------. | Menu ||
     | | . ./\ . . . . . ./\ . . . | |      ||
     | | . / .\. . . . . / .\. . . | |      ||
     | | ./. . \ . . . ./. . \ . . | |      ||
     | | / . . .\TRACE AREA. .\. . | |      ||
     | | . . . . \ . ./. . . . \ . | |      ||
     | | . . . . .\. / . . . . .\. | |      ||
     | | . . . . . \/. . . . . . \/| |      ||
     | `---------------------------' `------'|
     | .-----------------.        msec       |
     | | Cursor Readouts |                   |
     | `-----------------'                   |
     | Message Line                Status    |
     |---|---|---|  Key Options  |---|---|---|



The Y-axis units are controlled by the input range of the data acquisition Board and by the current trace magnification set by PgUp and PgDn. At start-up, the magnification is set to show the full-scale input range of the board. For example, if your board is set to 1 Volt full scale, the waveform axis will extend from -1.0 to 1.0 and the units will read 'Volt'. If the range is 100 mV full scale, the axis will run from -100 to 100 and the units will read 'mVolt'.

You can force the magnification back to full scale (or a preset value) at any time via SHIFT-HOME, and return to where you were via SHIFT-END.

When the Units option is active, the 'Volt' will change to correspond to whatever units you set in the User Units Control Menu, such as PSI, g, or Nt, with the appropriate prefix.

The Virtual Source, which is active at start-up instead of Board, always assumes the same range as the board.

When the FFT option is active the Y-axis becomes unipolar. If the RMS option is also active, the axis will be rescaled and 'RMS' will be appended to 'Volt' or to the user unit.

If the FFT Y-log option is active the axis is 'dBr:FS', which is short for 'dB re: Full Scale'. This changes to 'dB PSD' if the PSD option is also active.

If Mic Cal is active, the units are typically 'dB SPL'. If Spkr Cal is active, they typically show 'dB:V/Pa' for use in calibrating an unknown microphone. Other units than SPL and Pa can be used if they are specified when creating the Mic Cal file. When both Mic Cal and Spkr Cal are active (to show the transfer function of a probe tube or electrical network, for eaxmple), the units are simply dB.



The X-axis depends on the sample rate and number of points displayed. For an uneXpanded waveform display, the total time shown will be the number of points N times the sample period. The units will typically be in µsec, msec, or sec, as appropriate. If trigger delay is used, the X-axis will be shifted by the delay amount. If the delay is negative, a solid axis-color bar will appear below the negative portion of the axis, with the time labels shown in inverse video. The end of the bar is thus an easy way to tell the trigger sample point at a glance.

In FFT mode, the uneXpanded spectrum X-axis shows frequencies from 0 to half of the sample rate, with units typically in kHz or Hz. If the CPM option is active, the units are CPM with the appropriate prefix. For example, 10 kHz = 600 kCPM.

If the X-log option is active, the same frequency range is shown with a logarithmic scaling.

In Spectrogram mode, the X-axis shows time units. The exact duration of a spectrogram sweep depends on sample rate, number of points N, and processing time. Daqarta calibrates this "on-the-fly" by timing the first column of the display sweep and extrapolating, so the true overall axis may be slightly different due to changing conditions during the sweep. In particular, Triggered operation may produce unpredicatable timing variations that can result in substantial errors if the triggers come infrequently.


This will show TRIG if the Trig option is active, or FREE if it is not. It may seem redundant, since you can usually see if the Trig option is active in the Key Options area, but it is included on the top line with other pertinent information because this same line is shown as a header for text output files. Also, the Key Options area may be covered by the mini-Help screen if you are trying to view Help text while acquiring data.

The Trigger Status will also change from TRIG to FREE if the Free option is selected from the Trigger control menu.


This is where the action is: Waveform, Spectrum, or Spectrogram displays are shown here.


When you toggle this off via the V-key, the trace is not updated until you enter Pause mode or change some other mode like going from waveform to spectrum display. Although this is not an option you will normally want to turn off, there are times when that is desireable.

If you are collecting averages of many sweeps on a slow CPU, this will allow the average to run faster by avoiding the time otherwise used to draw each trace. (This is also a "cheater" method some programs use to claim high performance, especially if they have poor screen update routines.) As soon as the average is Done and Pause mode is automatically entered, the final result will be displayed.

If you are generating stimuli in Sequential mode, either with a Stimulus Generator module or with the Pulse source, you may sometimes require high repetition rates for the proper operation of the experiment. There will be some lower limit to the Cycle time you can set and still obtain the desired (SPEC) presentation rate, due to the total of all processing time needed between sweeps. Turning View off reduces the minimum Cycle time, allowing more stimulus presentations per second. Although the difference is of course greatest on slow machines, faster systems can still benefit, especially if the trace is very dense or "busy". Also, if the trace is quite variable in density from one sweep to the next (due to spurious noise bursts, for instance), turning View off can help assure that the SPEC stimulus rate is maintained when you are running near the minimum Cycle time.

While View is off, the most recent trace will remain visible. A 'VIEW OFF' reminder will appear in the upper right corner of the trace as a reminder that this is not the true incoming data. The cursor readouts will continue to function properly on this "old" trace data.

The true data will be shown whenever activity is Paused, either manually via the P-key or at the completion of an average or single-sweep. In the Paused condition the 'VIEW OFF' message will not be shown, since the screen display is correct.


A typical title line (above the trace area) is:

    512 pt PsS Rect Waveform

'512 pt' is the number of points N used to compute the trace, either 256, 512, or 1024.

'PsS' is the source of the incoming data, here shown as the Virtual Source. If the data acquisition Board is active, this changes to show the input channel, such as Ch0 or Ch1.

'Rect' is the active data window function. Here a Rectangular window indicates that there is no window in use. If the Windo option is active, this changes to whatever window type has been set in the Window control menu, such as 'Hamm', 'Hann', etc.

'Waveform' is the display mode. If the FFT option is active this changes to 'Magn Spectrum', or 'Powr Spectrum' if the Y-log option is also active. It changes to 'Spectrogram' if that mode is active.


When either waveform or spectrum averager is running, this shows the number of sweeps accumulated so far. The count is labeled to show which averager is in use, such as '32 Wave' or '64 FFT', since it is possible to toggle the display between modes while the average continues in its original mode.

If instantaneous data is displayed during an average, the count is shown surrounded in parentheses, like '( 32 FFT)'. This will be the case when using the \-key to toggle to INST mode, or when toggling FFT off to view the waveform while an FFT average is running. (When a waveform average is running you can toggle FFT on and see the FFT of the waveform average, but there is no provision to show the analogous inverse FFT of a spectrum average.)


The Speed readout gives an indication of the relative performance of Daqarta and your system with respect to the sample rate. When the Virtual Source is active, this tells how fast Daqarta can generate data, compared to how fast it could be acquired by sampling a real source:

 FAST  Data generation faster than real sampling.
 SLOW  Data generation slower than real sampling.
 SPEC  Data generation takes same time as real sampling.

No matter what the Speed indication, all Daqarta displays and data will be correct... only the screen update rate is affected. If Speed is FAST, you can enable the Timed option with ALT-T to add just the proper delay to get SPEC.

When Trigger Cycle is active to acquire data (and/or produce stimulus outputs) at a selected rate, the speed readout will show SLOW when running in Sequential mode if the time to acquire and process each sweep is longer than the indicated Cycle value. Otherwise, it will add as much dead time as needed to get SPEC... it will never show FAST.

When the Board and RTime options are active, the Speed display shows a value followed by GAP or OVL. GAP values indicate the samples skipped while waiting for a trigger or due to slow processing. OVL values (possible only in untriggered FREE mode) indicate the number of samples from the end of the last sweep that are included in the current one due to fast processing.


Control Menus pop up to the right of the trace area, in response to hitting a Key Options CTRL-key combination. The Virtual Source menu appears by default at start-up. Hold the CTRL key down to see the other menus available.

Certain menus will respond appropriately to the current state of other key options. For example, if Board is active, CTRL-B brings up the data acquisition Board menu, otherwise you'll get the Virtual Source menu. Similarly, CTRL-A gives the Waveform Averager or the Spectrum Averager menu depending on whether the FFT option is active. The CTRL-T Trigger menu differs if Virtual Source or Board is active, and also if RTime is active.

The menu variables are mostly "live", in the sense that changes are reflected immediately in ongoing operation. This is why menus don't pop up over the trace area as in certain "other" systems... the trace and menu are both active, so you can scroll values and observe changes immediately.

To change an item, move the menu cursor to it with the Up/Dn or CTRL-Up/Dn cursor keys and hit ENTER or CTRL-ENTER. (You will need to use the CTRL- keys when this Help system is active.) There are several types of menu items, and each has a slightly different action as noted below:


This is a stack of adjoining item boxes, only one of which can be active at a time, as shown by an inverse video highlight. Move the menu cursor to another item in the group and hit ENTER (or CTRL-ENTER), and the highlight moves to the new item.


These are simple two-state (On/Off, Yes/No, etc) items that can be toggled between the two states just by hitting ENTER. One of the states (On, Yes, etc) is usually shown highlighted when it is active to make it easy to tell at a glance. There are also certain three-state items that step through the sequence of states via repeated hits of ENTER. Toggle options really do the same sort of thing as pick list items, but they take up less menu space. They are also simpler to use than a submenu that pops up with a pick list.


Hitting ENTER on one of these items changes the menu cursor to a double-headed vertical arrow, allowing the item to be changed by scrolling the same Up/Dn or CTRL-Up/Dn keys that normally move the cursor. Hit ENTER again to accept the current state or value and restore the normal menu cursor, or ESCape to restore the original state or value.


These items allow scrolling of values as with the above cursor items, and also direct keyboard entry. When you hit ENTER, the menu cursor changes to double triangles (like the above doble-headed vertical arrow cursor without the arrow "shaft"). You may then proceed to scroll the value as desired with the Up/Dn or CTRL-Up/Dn keys. At any time, you may enter a new value directly. As soon as you hit the first numeral key (or minus key), an 'Enter value: ' prompt appears on the message line and the menu cursor changes to a filled-in D shape to indicate Direct entry in progress. Type in the complete number on the message line and hit ENTER, and the new value will replace the old one in the item.

If you hit ESCape before you hit ENTER, that will restore cursor adjust mode and the prior value.

If you hit CTRL-1 to CTRL-5 instead of ENTER, the new value will also be copied to the associated field of the comment line as a convenient way to label the trace.

The direct entry system is not available while the Help Index is active, since the text keys are dedicated to navigating the index.

If you wish to enter a decimal fraction less than 1, it must be preceded with 0 to trigger the direct entry mode since the period alone is not recognized as a numeral:

For very large or small values, direct entry allows allows either exponential notation or standard scientific prefixes. The following are all equivalent:


You can use 'u' as a shortcut instead of µ for the 'micro' prefix, although ALT-u will enter it directly. You can also use either 'k' or 'K' for 'kilo'. There must be no spaces in the entered number, and the base units are not entered. For example, you enter 1.234m for 1.234 mV, or 100k for 100 kHz.

If you don't enter a prefix or exponent, Daqarta may prompt you for one in cases where you might have forgotten it, such as if you enter 50 for the sample period... you probably don't want a period of 50 seconds! Likewise if you enter 500 instead of 500m for the trigger level, you probably don't mean 500 Volts. If this really is what you want, when you get the

    Enter prefix:

prompt, just hit ENTER and that's what you'll get.

Note also that if you are trying to use exponential notation and enter E but forget the exponent value, Daqarta will assume that you mean Exa or 10^18... probably not what you intended!

Daqarta also supports another form of notation that is popular in Europe, whereby the decimal point is replaced with the prefix character. This saves space when printing values on small electronic components or schematic diagrams, and eliminates any international ambiguity over the use of a period versus a comma as the decimal point. In Daqarta, it also saves one keystroke. The following columns are equivalent:

    1.234m   =    1m234
    12.7k         12k7
    1.02M         1M02


Certain menus, such as Color menus, have upper item pick lists that allow adjustment of values in a submenu that appears lower on the same menu "page". The submenu is identified by having a "drop-shadow" box around it, to make it look like it is at a different level. Hitting ENTER to select an upper item leaves a place-mark (*) there and moves the cursor to the submenu, where the items to be adjusted will apply to the selected upper item. You can then adjust the submenu items just as for any other menu item.

For example, if you are in the main Colors menu and move the cursor to the TRACE item, hitting ENTER will leave the * place-mark there and the cursor will jump down to the submenu box. There you may adjust the Color value or the Red, Grn, Blu values and the trace color will change. When you are done adjusting any item there and have hit ENTER to allow movement between the submenu items, you can hit ESCape to jump back to the TRACE item.

There are also submenus that pop up over part or all of the main menu in response to hitting ENTER on a main menu item, allowing for extended options. As with the same-page submenus, they are denoted with a drop-shadow box surround. Within a submenu, operation is the same as for the main menu. ESCape while the cursor is not in an adjust mode will remove the submenu and return to the main menu.


Sometimes there are "parallel" main menu or submenu pages that you can access via CTRL-PgUp and CTRL-PgDn. A small double-headed vertical arrow symbol appears at the upper right in such menus to let you know that these other pages are present, as in the DDisk Write and DDisk Read menus.

When you are in the Sgram Colors menu, CTRL-PgDn brings up the ColorMap menu page. In this case, however, you must hit CTRL-PgDn again to return to the Sgram COLORS menu because CTRL-PgUp has a special function in any Color menu: It pops up the Palette Operations submenu.

The Advanced Stimulus Signal Generator menu (CTRL-G for StGen if you have installed the STIM3A module in your DQA.CFG file) makes abundant use of alternate menu pages, since there are multiple parallel generator functions for each DAC analog output, and 8 parallel bit functions for the digital output.


The trace cursors are the solid and dashed vertical lines that are superimposed on the trace. The solid cursor is moved by the right/left cursor keys, and the dashed cursor by ALT with those keys. The solid cursor readout is the left column, indicated by a solid horizontal line between the upper Y-value block and the lower X-value block. Similarly, the dashed cursor readout column next to it has a dashed line between the blocks. The right delta column shows the vertical and horizontal differences between the two cursors.

The cursors and readouts are not shown when Help is active, or if you toggle the ViewC option off. They are also not shown in Spectrogram (Sgram) mode.

You can use the C-key (CursX) or grey minus-key to exchange which cursor moves with the ALT cursors and which moves with the unshifted cursor keys.

Cursor action is "dynamic", in that the longer you hold the key down the faster the cursor moves. You can use the CTRL-K Keyboard control menu to adjust the acceleration rate and the maximum speed, as well as the hardware auto-repeat action built into your AT keyboard controller, to suit your own preferences.

You can also use the Keyboard menu to adjust the averaging time of the readouts themselves, so the numbers don't become a blur with noisy data.


The trace cursors and the readout box may be removed by turning off the ViewC (View Cursors) option via SHIFT-V. This is done automatically under certain situations, such as during Spectrogram display, or when the Help system is active.

You will probably want to keep the cursors active most of the time, but you may want to turn them off to reduce trace clutter when printing the screen, for instance.


This line serves multiple purposes:
  • Shows error messages.
  • Shows the current SHIFT, CTRL, or ALT key status.
  • Prompts for user input.
  • Accepts prompted direct input values, file names, etc.

When not in use for any of the above, the message line shows any comment text you have entered via the Edit option. If the comment is temporarily replaced with an error message, it will be restored by the next key press. If you save data to a file or to trace memory, the comment will be saved along with it.


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