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
(Free Music... Forever!)

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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Use Level

Macro: UseLevel

As noted under the Volume dB control section, Daqarta can obtain resolution much finer than the actual attenuator step sizes by making small adjustments using the effective Level settings for each Stream. The Use Level button selects that mode of operation. It is disabled unless Use dB is also selected, which is only possible after calibration.

When Use Level controls the effective Level, it does so transparently; there are no visible changes to actual Level control values. The effective value is computed as the product of the control setting times the appropriate factor needed for attenuator step interpolation.

So, why would you ever not want Use Level? If you want to change loudness with a minimum of clicks and pops. The reason is that when any parameter that affects waveform generation is changed, the sound is restarted with the new changes in effect. That applies to Level, even when it is done automatically via Use Level volume changes. Since the new sound doesn't just continue from where the old sound stopped, there will almost certainly be a discontinuity, which causes an audible click.

You can use the GenUpdate macro to avoid these clicks in certain situations, especially during macro control of volume or level.

If Use Level is not in effect, simple volume changes will only use the Wave and Master attenuators of the mixer. Those just operate on the analog output without affecting the computed wave, eliminating the need for a restart.

However, note that there may still be softer clicks depending on your sound card, driver, and even Windows itself. These are the same clicks you would hear when moving the Windows Mixer volume sliders for any sound on your system.

Macro Notes:

UseLevel=1 turns Use Level on, UseLevel=0 turns it off, and UseLevel=x toggles between on and off.

Note that this command is enabled only when Use dB is on. Otherwise, the macro may abort with an error message. To be safe, give UseCal=dB before UseLevel.

See also Generator Attenuator Options Dialog.


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