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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.
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Main Tone Frequency

Controls: Gen Dlg >> Stream >> Tone Freq >> Main Freq
Macro: ToneFreq

Controls the frequency of the waveform for the stream.

Frequency may be set to any value up to the Nyquist frequency, which is half the actual sample rate.

This control is present in the main Tone Frequency dialog, and also in the AM, FM, and PM modulator dialogs for convenience. It is not available when the main Wave is one of the Noise types.

The maximum frequency resolution is limited by the effective sample rate:

 
Resolution (Hz)  =  Sample Rate  / (65536 * 8192)
 

For a sample rate of 48000 Hz, the resolution is thus 0.000089 Hz.

The actual frequency entry process is controlled by the Step Mode shown on the button below it.

When Play Wave type is active, the Freq control changes to Rate. The Play Rate control allows Rate to be set relative to the absolute rate (Abs), as recorded originally, or relative to the current sample rate (Rel).

Note that when Freq is set to 0, the output is a constant level controlled by the Phase setting; at a Phase of 90 degrees the output of a Sine wave is a constant 100%, for example. This can be useful when used with Burst or Phase Modulation to modulate another stream.


Macro Notes:

L.1.ToneFreq=1k sets Left Stream 1 Tone Frequency to 1000 Hertz.

L.1.ToneFreq=>1 increments the frequency to the next higher Frequency Entry Step, while L.1.ToneFreq=>-1 decrements to the next lower step. Only +/-1 step is accepted.

Note that the ToneFreq command will change the indicated frequency value even if that stream is using a Noise-type Wave that doesn't allow normal user access to the Frequency dialog. In that case, there will be no change to the output signal until a non-noise Wave type is selected.


See also Main Phase, Tone Frequency Dialog, Waveform Stream Controls.


Applications:

Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery

Vehicle pass-by noise

Product test

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