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:



Spectrum Analyzer

Signal Generator

(Absolutely FREE!)


Pitch Tracker


DaqMusiq Generator
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Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Spectral Event

    MHz Frequencies

Data Logger

Waveform Averager


Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls


Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording



Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery


Product test

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Meter / Match Mode Control

Ideally, your computer should be able to perform an Auto-Calibrate operation by monitoring the output level using the sound card input, while the output is cycled through all the attenuator settings. But some older sound cards don't allow simultaneous input and output ("full-duplex") mode, so you may need to calibrate manually here.

There are two basic ways you can use these dialogs to help in calibrating your mixer attenuators: Direct measurement via a meter, or indirectly via matching two signals.

Regardless of which method you use, you will need to perform separate calibrations for both Wave and Master; these are separate attenuators which typically have totally different steps.

When you are calibrating the Wave output, set Master Volume to get a large overall output signal before you start. (For Match mode, both Left and Right Master should be equal; use the Volume Track button to simplify this.) If you are calibrating Master, set Wave Volume to get a large output instead.

The output should not be distorted when the range being calibrated is at maximum loudness, since the voltage will not properly track with attenuator changes. For these purposes you can judge distortion by ear: Use the Daqarta volume controls with the calibration (Wave or Master) volume at maximum, and run the other (Master or Wave) from low to high. If the quality or timbre of the sound changes above a certain step, it indicates distortion; set that volume control to the maximum undistorted step.

Note that although sound cards typically have only 16 or 32 actual steps on each attenuator, Windows pads this up to 192 overall by adding dummy steps to give higher apparent resolution. So during your manual calibration, expect to see many steps where there is no change from the prior step.

See also Meter Measurements, Match Measurements, Calibrate Wave / Master, Generator Attenuator Options Dialog


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