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!

Generator Introduction and Features

The Daqarta Generator allows any Windows-supported sound card to become a continuous real-time 8-channel signal generator. Unlike systems that simply play back a static buffer, Daqarta's continuous generation allows not only extremely fine frequency resolution, but also extremely long tone bursts and frequency sweeps (hours or days) and complex signal interactions. For example, two frequency components that are set to differ by 0.0001 Hz will only be in phase once every 2.78 hours. Modulation cycles can be combined to get even longer intervals, many millions or even billions of years.

There are two different output modes: Normal stereo/mono, and Multi-Channel.

Normal stereo/mono mode is the default, which uses the two output channels available on all modern sound cards. These may be used together for stereo, or independently. Buttons allow the two outputs to be quickly swapped, or to force one output to sound alone (Solo), or to send one channel to both outputs (Dual). The default Generator setup has only the Left channel active, which produces the identical signal from both Left and Right outputs without use of the Dual button.

In stereo/mono mode each channel can be a combination of up to 4 independent signal streams, labeled L.0 through L.3 and R.0 through R.3, each with its own set of dialog controls. Each stream has independent control of Wave type, Frequency, level, and combination of modulators. Alternatively, instead of going to the output, a stream can be used as a modulation source for other streams of the same output, allowing extremely complex modulation schemes.

In Multi-Channel Outputs mode you can use up to 8 independent output channels, each of which can use any combination of the 8 Left and Right streams... including those streams that are used as modulation sources, which normal stereo mode doesn't allow you to also use as direct outputs. You can thus use a dedicated modulator output channel as a sync input to external devices, for example.

You can use Multi-Channel Outputs even if you don't have a multi-channel sound card; you'll of course only have two output channels, but you can still combine up to 8 streams on each channel instead of only 4.

Complete signal configurations may be saved to files for automatic load on startup, or may be saved or loaded at any time during operation.

Waveforms, resolution 0.0001 Hz, 0.05 degrees:

Random sources:

  • White noise, uniform distribution
  • Gaussian (normal) distribution white noise
    • (Adjustable Standard Deviation)
  • Pink noise
  • Band-limited noise
    • (Adjustable band/gap edge frequencies and shapes)

Each waveform can be modulated by any or all of:

Random (noise) sources do not repeat for over 6 million years. They can use Burst or AM modulators, and can also be slowed, stepped, smoothed, quantized, or time-shifted. (Two identical noise sources combined with a time shift give comb-filtered noise, for example.)

AM, FM, and Phase/Slope/Width modulators can use simple sine modulation (adjustable frequency, phase, and depth) or one or more of the other streams as modulators. For example, you can have a basic Pulse waveform, and apply FM that uses a noise generator as its source to provide controlled jitter. And that noise source can use AM so that the jitter changes in strength, and the AM source can be an Arb or Play file that is stepped through slowly to provide a test program of different jitter amounts.

A sine modulator or another stream can also be used to control Burst duration parameters, including the number of bursts per train.

Similarly, a sine modulator or another stream can control certain random source parameters. Modulation of quantization levels and quantizer offset bias allows creation of random pulses or bursts like a "Geiger counter". Modulation of the relative time shift between two random sources allows creation of "jet" sound effects due to changing comb filtering.


See also Basic Generator Operation - Your First Output Sound, Signal Generator Control Dialog


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