Rigol MSO1000Z Series Programming Manual page 157

Chapter 2 Command System
Users can omit one or multiple parameters. When all of the parameters are omitted,
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the commands only select the waveform shape but do not modify the parameters.
The four parameters (<freq>, <amp>, <offset>, and <phase>) are in order. You

can not omit one parameter and set the one/ones behind it. For example, you can not
omit <freq> and set <amp> directly.
MSO1000Z/DS1000Z Programming Guide
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