Daqarta
Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
Software for Windows
Science with your Sound Card!
The following is from the Daqarta Help system:

Features:

Oscilloscope

Spectrum Analyzer

8-Channel
Signal Generator

(Absolutely FREE!)

Spectrogram

Pitch Tracker

Pitch-to-MIDI

DaqMusiq Generator
(Free Music... Forever!)

Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Period
    Event
    Spectral Event

    Temperature
    Pressure
    MHz Frequencies

Data Logger

Waveform Averager

Histogram

Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls

Auto-Calibration

Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording

Accessibility

Applications:

Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery

Automotive

Product test

Contact us about
your application!

Full-Scale Range Dialog

Controls: Calibration Menu >> Full-Scale Range
Macros: RangeDlg, RangeIn... RangeWave, RangeOutMst

You can invoke this dialog from the Calibrate menu via ALT+C, R, or directly via CTRL+R.

This allows you to enter absolute calibration data for the sound card inputs and outputs. This information is needed in addition to the relative calibration of the attenuators in the sound card's mixer obtained via the Auto-Calibration dialog. Range controls for each line are disabled until it has been Auto-Calibrated.

Range information is stored with attenuator calibration information in the Daqarta0.ATN file that is loaded when Daqarta starts. If you make any changes to Range values, you will be prompted to save them when you exit Daqarta. If your system has more than one card (which you can select via the Device controls in the Start Preferences dialog), then the files may be called Daqarta1.ATN, etc. Note that the Output Device number is used here. The Input Device number is usually (but not always) the same.

The Daqartan value may also be changed via shortcut command-line parameters for use with multiple desktop icons when managing multiple devices.

The value to be entered for each line in the Range dialog is the level of a signal that will just produce a full-scale response on the most-sensitive Input range. For Outputs, the value to be entered is the maximum level produced when the Generator is creating a full-scale signal. In both cases, "level" means amplitude in the mathematical sense of half the peak-to-peak difference of a symmetrical waveform like a sine wave. The default value of 1.000 implies that the wave runs between +1.000 volts and -1.000 volts. In other words, this is not an RMS value such as you might read from the AC range on a voltmeter.

The exact lines that you see and which ones are enabled depends upon your specific sound card. Typically, there are controls for each Input line and Wave Out, but Master In and Out are disabled since they have no external connection. Some devices such as USB microphones may have only Master In, but no other Input lines.

The internal format for the Range value supports about 5 integer digits and 5 fraction digits. If you need to enter a very small value like 0.58 mV (0.00058 V), enter 0.58 here and enter 1000 for External Gain.

A given Range entry applies equally to both Left and Right channels, which are assumed to be identical inside the sound card. Use the External Gain dialog for any external amplification or attenuation you provide.

There are separate Stereo and Mono entries for Input lines. Most sound card inputs sum the Left and Right channels together when only one is active, and cut the sensitivity in half. So, the Mono Range entry should typically be twice the value of the Stereo Range entry.

Use single-channel Input operation with caution, to prevent contamination by the other channel. Be sure to set the other Line Level (and Master Level, if present) to minimum (most-negative value). Note that this may not completely shut off that channel, so you may need to insure that there is no signal present at that input.

There are two basic approaches to obtaining full-scale range values: You can start by measuring the Generator output with an external voltmeter and setting the Output Range, then apply the now-calibrated signal to the input to get the Input Range. Or, you can start by applying a known input signal to calibrate the Input Range and then use that to read the Generator output to determine the Output Range.

The Output Voltage Method is preferable if you have a sensitive meter; the Input Voltage Method is suitable for use with inexpensive meters.

Some sound cards invert signal polarity on input or output channels, or both. Be sure to see Polarity Determination to insure that the trace display matches the real world.


Macro Notes:

RangeDlg=1 opens the Full-Scale Range dialog, RangeDlg=0 closes it, and RangeDlg=x toggles between open and closed.

Note that you do not need to open this dialog to change most of its controls directly via macro command, as long as they are enabled.


RangeDlg?0 is a read-only variable that returns the current full-scale range for channel 0. You may use channels 0-3 here, given as a single digit. Alternatively, you can use V to specify the current Ch Channel Select number. A default range value of 1.00 is returned for a channel number outside the 0-3 range, whether specified directly or via the V option.

    0 = Left In
    1 = Right In
    2 = Left Out
    3 = Right Out
    V = Ch value (0-3)

For input channels 0 or 1 the return value takes into account whether your sound card has separate input lines and if so which one is selected, as well as whether the input is in stereo or mono mode (since full-scale ranges may differ).

For output channels 2 or 3 it considers whether the sound card has separate Wave controls or uses only Master volume.

However, in each case the returned value is only the full-scale range; it does not include any attenuation or gain due to Input Line or Master levels, nor to output Wave or Master volume settings.

See Macro Data Unit Conversions for a discussion of how to use this variable together with others to obtain actual volts or User Units from ADC or DAC values returned by certain macro math and macro array functions.


To set or read specific lines in the Full-Scale Range dialog, use RangeIn0 to RangeIn7 for stereo input ranges, or RangeInMst if your sound card does not have separate range controls for each input line.

For mono input ranges use RangeIn0M to RangeIn7M, or RangeInMstM if there are no separate input controls.

There is no difference between stereo and mono output ranges. Use RangeWave for cards that have a separate Wave volume control, or RangeOutMst if not.

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