Data AcQuisition And Real-Time AnalysisScope - Spectrum - Spectrogram - Signal Generator
Software for Windows
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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.
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.
Note that in addition to the standard waveforms, Arb allows easy access to 31 non-standard waveforms included with the Daqarta distribution as .DAT files. These were created with the Arb_From_Equation macro Mini-App, which incudes full code and waveform images, and allows easy modification for creating your own waveforms.
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