如何禁用函数发生器切换范围功能？

默认情况下，33250A和33220A功能/任意波形发生器启用了自动量程。
这允许发生器自动选择输出放大器和衰减器的最佳设置。
禁用自动量程的优点是消除了在改变幅度时由衰减器切换引起的瞬间中断。
然而，当将幅度降低到远低于预期范围变化时，幅度和偏移精度和分辨率（以及波形保真度）可能受到不利影响。
可以从前面板（效用 - >输出设置 - >范围 - >自动/保持）或通过命令VOLTage禁用自动量程：RANGe：AUTO OFF | ON | ONCEOnce将范围设置为Hold（与Auto相比）
），电流放大器/衰减器设置将保持不变。
作为最佳实践，在设置范围之前将振幅调整到最大所需电压是个好主意。



     以下为原文

  By default, the 33250A and 33220A Function/Arbitrary Waveform Generators have Autoranging enabled.  This allows the generator to automatically select the optimal settings for the output amplifier and attenuators.  The advantage of disabling autoranging is to eliminate momentary disruptions caused by switching of the attenuators while changing amplitude.  However, the amplitude and offset accuracy and resolution (as well as waveform fidelity) may be adversely affected when reducing the amplitude well below the expected range change. 

The Autorange may be disabled either from the front panel (Utility -> Output Setup -> Range -> Auto/Hold) or by the command VOLTage:RANGe:AUTO OFF|ON|ONCE

Once the range is set to Hold (as compared to Auto), the current amplifier/attenuator settings will be held constant.  As a best practice, it is a good idea to adjust the amplitude to the maximum desired voltage before setting the range.