Glossary
TDS 620A, 640A, & 644A User Manual
Sample acquisition mode
The oscilloscope creates a record point by saving the first sample
during each acquisition interval. That is the default mode of the
acquisition.
Sample interval
The time interval between successive samples in a time base. For
real-time digitizers, the sample interval is the reciprocal of the sample
rate. For equivalent-time digitizers, the time interval between succes-
sive samples represents equivalent time, not real time.
Sampling
The process of capturing an analog input, such as a voltage, at a
discrete point in time and holding it constant so that it can be quan-
tized. Two general methods of sampling are:
real-time sampling
and
equivalent-time sampling.
Select button
A button that changes which of the two cursors is active.
Selected waveform
The waveform on which all measurements are performed, and which
is affected by vertical position and scale adjustments. The light over
one of the channel selector buttons indicates the current selected
waveform.
Side menu
Menu that appears to the right of the display. These selections ex-
pand on main menu selections.
Side menu buttons
Bezel buttons to the right of the side menu display. They allow you to
select items in the side menu.
Slope
The direction at a point on a waveform. You can calculate the direc-
tion by computing the sign of the ratio of change in the vertical quanti-
ty (Y) to the change in the horizontal quantity. The two values are
rising and falling.
Tek Secure
This feature erases all waveform and setup memory locations (setup
memories are replaced with the factory setup). Then it checks each
location to verify erasure. This feature finds use where this
digitizingoscilloscope
is used to gather security sensitive data, such as is done
for research or development projects.
Time base
The set of parameters that let you define the time and horizontal axis
attributes of a waveform record. The time base determines when and
how long to acquire record points.
Trigger
An event that marks time zero in the waveform record. It results in
acquisition and display of the waveform.