Tektronix 11801C User Manual page 162

Autoset
3 12
Setting the Stan Mask Offset Adj selector to On causes the instrument to
adjust the vertical offset during a standard mask autoset to make the wave
form match the selected standard mask more closely. Setting this selector to
Off turns off vertical offset adjustments during a standard mask autoset.
This feature only applies to 19 of the standard masks. They are:
H ITU T G.703 Standard Masks
Single Pulse 64 kb/s
Double Pulse 64 kb/s
Data Pulse 64 kb/s
Timing Pulse 64 kb/s
Pulse 1.544 Mb/s
Sym Pair 2.048 Mb/s
Coax Pair 2.048 Mb/s
Sym Pair 6.312 Mb/s
Coax Pair 6.312 Mb/s
Pulse 8.448 Mb/s
Pulse 32.064 Mb/s
Pulse 34.368 Mb/s
Pulse 44.736 Mb/s
Pulse 97.728 Mb/s
H ANSI T1.102 Standard Masks
Digital Signal 1 (DS1) 1.544 Mb/s
Digital Signal 1 (DS1 old) 1.544 Mb/s
Digital Signal 1C (DS1C) 3.152 Mb/s
Digital Signal 2 (DS2) 6.312 Mb/s
Digital Signal 3 (DS3) 44.736 Mb/s
For all other standard masks, vertical offset is always adjusted by the stan
dard mask autoset, regardless of how this option is set in the Instrument
Options pop up menu.
Reference