Getting Started 1
Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide 41
 
11. Additional waveform 
controls
The additional waveform controls consist of:
• [FFT] key — provides access to FFT spectrum analysis function. See Chapter 4, “FFT 
Spectral Analysis,” starting on page 89.
•[Math] key — provides access to math (add, subtract, etc.) waveform functions. See 
Chapter 5, “Math Waveforms,” starting on page 99.
•[Ref] key — provides access to reference waveform functions. Reference waveforms are 
saved waveforms that can be displayed and compared against other analog channel or 
math waveforms. Also, measurements can be made on reference waveforms. See 
Chapter 6, “Reference Waveforms,” starting on page 127.
• [Digital] key — Press this key to turn the digital channels on or off (the arrow to the left will 
illuminate).
When the arrow to the left of the [Digital] key is illuminated, the upper multiplexed knob 
selects (and highlights in red) individual digital channels, and the lower multiplexed knob 
positions the selected digital channel.
If a trace is repositioned over an existing trace the indicator at the left edge of the trace will 
change from Dnn designation (where nn is a one or two digit channel number from 0 to 15) 
to D*. The "*" indicates that two or more channels are overlaid.
You can rotate the upper knob to select an overlaid channel, then rotate the lower knob to 
position it just as you would any other channel.
For more information on digital channels see Chapter 7, “Digital Channels,” starting on 
page 131.
• Multiplexed scale knob — This scale knob is used with Math, Ref, or Digital waveforms, 
whichever has the illuminated arrow to the left. For math and reference waveforms, the 
scale knob acts like an analog channel vertical scale knob.
• Multiplexed position knob — This position knob is used with Math, Ref, or Digital 
waveforms, whichever has the illuminated arrow to the left. For math and reference 
waveforms, the position knob acts like an analog channel vertical position knob.
•[Serial] key (between channel 1 and 2 keys) — This key is used to enable serial decode. The 
multiplexed scale and position knobs are not used with serial decode. For more information 
on serial decode, see Chapter 8, “Serial Decode,” starting on page 149.
12. Measure controls The measure controls consist of:
• Cursors knob — Push this knob to select cursors from a popup menu. Then, after the popup 
menu closes (either by timeout or by pushing the knob again), rotate the knob to adjust the 
selected cursor position.
•[Cursors] key — Press this key to open a menu that lets you select the cursors mode and 
source.
•[Meas] key — Press this key to access a set of predefined measurements. See Chapter 15, 
“Measurements,” starting on page 243.