Glossary
TDS 620A, 640A, & 644A User Manual
Holdoff, trigger
A specified amount of time after a trigger signal that elapses before
the trigger circuit will accept another trigger signal. Trigger holdoff
helps ensure a stable display.
Horizontal bar cursors
The two horizontal bars that you position to measure the voltage
parameters of a waveform. The oscilloscope displays the value of the
active (moveable) cursor with respect to ground and the voltage value
between the bars.
Interpolation
The way the digitizing oscilloscope calculates values for record points
when the oscilloscope cannot acquire all the points for a complete
record with a single trigger event. That condition occurs when the
oscilloscope is limited to real time sampling and the time base is set
to a value that exceeds the effective sample rate of the oscilloscope.
The digitizing oscilloscope has two interpolation options:
linear
or
sin(x)/x interpolation
.
Linear interpolation calculates record points in a straight-line fit be-
tween the actual values acquired. Sin(x)/x computes record points in
a curve fit between the actual values acquired. It assumes all the
interpolated points fall in their appropriate point in time on that curve.
Intensity
Display brightness.
Interleaving
The way the digitizing oscilloscope attains high digitizing speeds by
combining the efforts of digitizers of several channels. For example, if
you want to digitize on all channels at one time (four on the
TDS 644A & TDS 640A and two on the TDS 524A & TDS 620A),
each of those channels can digitize at a maximum real-time speed of
250 megasamples per second.
Knob
A rotary control.
Logic state trigger
The oscilloscope checks for defined combinatorial logic conditions on
channels 1, 2, and 3 on a transition of channel 4 that meets the set
slope and threshold conditions. If the conditions of channels 1, 2, and
3 are met then the oscilloscope triggers.
Logic pattern trigger
The oscilloscope triggers depending on the combinatorial logic condi-
tion of channels 1, 2, 3, and 4. Allowable conditions are AND, OR,
NAND, and NOR.