Adjusting The Vertical Setup - Tektronix TLS 216 User Manual

Adjusting the Vertical Setup

To Understand the Vertical Controls
Clipping
Vertical Scaling vs.
Display Mode
TLS 216 User Manual
The TLS 216 Logic Scope allows you to scale (change the volts/division
setting), position, and otherwise control waveform groups vertically on the
screen. To perform these basic operations, you use the vertical knobs and the
Group menu.
This article describes how to check the current vertical setup and how to use the
vertical controls to scale, position, offset, and set the bandwidth limit of any
waveform group you select. (See Selecting a Group and Channel, on page 3–117
to learn how to select a group.)
To effectively use the vertical controls, consider how they operate with regard to
the group display mode:
The vertical position, bandwidth, and offset controls operate directly on the
selected group regardless of its display mode: Analog, BusForm, or Timing
Diagram.
A group displayed in Analog mode changes vertical size on screen directly
with the Vertical Scale knob. The Vertical Scale knob adjusts the vertical
scale of the acquisition hardware regardless of the group display mode.
A group displayed in either BusForm or Timing Diagram mode has its
vertical display size set independently of the vertical scale. You set it directly
in divisions of difference between the logic HIGH and LOW values these
two modes display.
Vertical scale settings that result in input signal levels that drive the acquisition
hardware beyond +/–five divisions of its ground reference level (center screen,
with vertical position and offset set to zero) become clipped. Clipped waveform
groups cause the notice "Clipping" to appear above the Vertical Readout, in the
lower left corner of the display. In such a case, adjust the vertical scale (or offset)
until the notice disappears.
Just because the vertical scale setting does not directly control the size of
BusForm and Timing Diagram groups, does not mean you should ignore it.
Groups with waveforms clipped in Analog mode are clipped when delivered for
comparison against the display threshold levels in BusForm and Timing Diagram
modes. Clipped input signals may compare incorrectly and therefore result in an
incorrect digital representation of the input signals. (See Choosing a Group
3–7