Data AcQuisition And Real-Time AnalysisScope - Spectrum - Spectrogram - Signal Generator
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Frequency Entry Step Mode
The Step mode button makes it convenient to step by constant or exponential amounts between frequencies, or to set frequencies which will fall exactly on FFT spectral lines or musical notes.
This button appears below each main Freq control in the Generator, and opens a Frequency Entry Mode dialog when hit.
The Frequency Entry Mode dialog has controls for selecting Direct, Hertz, Lines, Octave, and Cents steps, and for setting their sizes. When a step mode is selected, it applies to all frequency entry controls, including modulator frequencies and Noise Band edges.
The step mode only affects a frequency being entered or adjusted; afterward, the set frequency remains even if the mode or step value is subsequently changed.
The step mode is a global variable throughout the Generator; it will appear in, and can be changed from, any Generator dialog with a frequency control that has this button. That includes main Tone Frequency, AM, FM, PM, Sweep and Noise Band dialogs, as well as the modulator dialogs for Timing Quantization, Bias, and Shift.
Note that due to the quantization action of step modes other than Direct, attempting to set frequency values lower than half the step size will result in an entered frequency of zero. This can be very disconcerting, for example, if you use a quantizing step mode when setting a carrier frequency, then forget that mode is still in effect when you later go to set a low modulator frequency.
Note that changing Sample Rate causes all Generator frequencies to be updated, which can provoke the above situation. Always set Sample Rate before setting Generator frequencies.
FstepDlg=1 opens the Step Mode dialog if a parent dialog showing its button is open, such as the Tone Frequency dialog or one of the modulator dialogs (Timing Mod, Burst Mod, AM, FM, PM, or Sweep). FstepDlg=0 closes it, and FstepDlg=x toggles between open and closed.
Note that you do not need to open this dialog to change controls directly via macro command.
You can set Fstep types by name, as in Fstep=Line, or you can use numeric values, variables, or expressions for setting, reading, or IF testing. For example, Fstep=A + B would set Line if A + B equals 2.
0 = Dir 1 = Hz 2 = Line 3 = Oct 4 = Cent
Note that if you use a name instead of a value in an IF test, it must be in quotes: IF.Fstep="Line".
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