Data AcQuisition And Real-Time AnalysisScope - Spectrum - Spectrogram - Signal Generator
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Macros: BurstRise, BurstRiseMod
This is the time or number of samples the burst waveform will take to rise from completely off to completely on. The shape of the rise is typically that of a cosine-power function, whose exponent is controlled by the Shape option. However, you may set the exponent to 0 to get a linear shape.
By making the rise longer, or the exponent smaller (not including 0 for linear), you reduce the amount of "spectral splatter" or audible click associated with the onset of the tone. In a detection experiment, the click might be audible where the tone itself is not, giving a misleading result.
But if you are determining the subject's detection threshold by recording neural responses, you must also take care not to make the rise too long, either, as explained in the Rise/Fall practical example for auditory evoked responses.
Burst Rise Modulation
Normally, you can ignore the small Rise pushbutton and just use the edit portion of the control. The button opens a Burst Time Modulator dialog that allows the Rise time to be modulated, either by a sine wave source with adjustable frequency and phase, or by some other stream source. You can also set the base Rise value from that dialog (it's just a duplicate of the main Rise control), as well as the modulation depth.
When modulation is applied, the effective Rise time is equal to the sum of the base Rise value plus the modulator scaled by the modulator depth. For example, if the depth is 10% then the effective Rise ranges from 90% to 110% of its base value. If the base Rise is 100 samples, the effective Rise will then range from 90 to 110 samples.
L.1.BurstRise=100 sets Left Stream 1 Burst Rise to 100 samples, assuming Smpl mode. It will set 100 seconds in sec mode. To be safe, use a SmplSec command to set the desired mode before using this command.
L.1.BurstRise=>1 increments and L.1.BurstRise=>-1 decrements by one sample, even in sec mode. Only +/-1 sample steps are allowed.
If the Burst Dialog is open, BurstRiseMod=1 opens the associated Burst Time Modulation dialog, BurstRiseMod=0 closes it, and BurstRiseMod=x toggles between open and closed. See further information under Burst Time Modulation.
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