Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
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Spectrum Analyzer

Signal Generator

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Engine Simulator

LCR Meter

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AM Modulation Frequency

Macro: AMmodFreq

This sets the AM modulator frequency when Source is set to Sine. The main Frequency Entry Mode affects this control as well.

One unusual use of AM is to produce controllable 2nd-harmonic distortion for testing purposes. If you set the AM Sine modulator frequency to match the main (carrier) Frequency, you can adjust the amount of the 2nd harmonic using the AM Depth control. (Use Peak mode for this). There will also be a DC term (the difference term, where both frequencies are equal) which you can control by adjusting the relative phases. With Depth at 100% the wave will be mostly positive when the phase difference is 0, mostly negative at 180 degrees, and symmetrical at 90 or 270.

The frequency resolution of this and all Generator frequency displays may be set between 0 and 9 decimal places via the Frequency Places option in the Frequency Step Mode dialog, invoked by clicking the button below the Main Freq control higher up in this AM dialog. (The button shows the current Step Mode, which defaults to Step Direct.)

Macro Notes:

L.1.AMmodFreq=100.5 sets the Left Stream 1 AM Modulation Frequency to 100.5 Hz.

AMmodFreq=>1 will increment or AMmodFreq=>-1 will decrement the current AM Modulator Frequency by 1 Frequency Step. Only +/-1 step is allowed per command, but the step size and type can be controlled via the Frequency Step dialog. Note: The Frequency Step setting affects the behavior of almost all Generator frequency controls.

See also Amplitude Modulation, Amplitude Modulation Dialog, Waveform Stream Controls.


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