Command Syntax

:MEASure:TBASe:METHod  {STANdard | UDEFined}

Query Syntax

:MEASure:TBASe:METHod?

Description

Selects the method used to define a waveform's top and base definitions. The command is equivalent to setting in the Top-Base Definition tab in the Configure Measurements dialog.

STANdard

Specifies that the levels be automatically determined. The top (100%) and base (0%) levels are relative or proportional to the signal amplitude. This is the default setting.

UDEFined

Allows you to enter absolute values for the top-base levels. When UDEFined is selected, use the commands shown in the following table to enter the top and base levels depending on the waveform type.

Commands Used to Enter Top and Base Levels

Waveform Type	Commands
Channels	:CHANnel{N}:UDEFined:BASe :CHANnel{N}:UDEFined:TOP
Eye Memory	:EMEMory{1:8}:UDEFined:BASe :EMEMory{1:8}:UDEFined:TOP
Waveform Memory	:WMEMory{1:8}:UDEFined:BASe :WMEMory{1:8}:UDEFined:TOP
Function	:FUNCtion{1:16}:UDEFined:BASe :FUNCtion{1:16}:UDEFined:TOP
T-Domain and S-Parameter Traces in TDR/TDT Mode	:TRACe{1:128}:UDEFined:BASe :TRACe{1:128}:UDEFined:TOP

Measurements Affected by :MEASure:TBASe:METHod

Instrument Mode
Oscilloscope	Eye	TDR/TDT
Average	Eye Amplitude	Average
Duty Cycle	Eye Height	Fall Time
Fall Time	Eye Width	Rise Time
Rise Time	One Level	Δ Time
Frequency	Zero Level	Time at Edge
Preshoot	Fall Time	Time at Amplitude
Oversoot	Rise Time
Period	Crossing Time
+ Pulse Width	Δ Time
— Pulse Width	Crossing %
Δ Time	Duty Cycle Distortion
Time at Edge	Signal to Noise Ratio
Time at Amplitude	Jitter
RMS	Extinction Ratio
Amplitude at Upper	OMA at Crossing
Amplitude at Middle	VECP
Amplitude at Lower	Bit Rate
OMA
Phase
Jitter

Example Command Sequence

:MEASure:TBASe:METHod UDEFined
:CHAN2B:UDEFined:BASe -125E-3
:CHAN2B:UDEFined:TOP 125E-3