
Operating Instructions—Type 324
External Trigger—Any signal applied to the Type 324
Oscilloscope T R IG OR H O R IZ IN PU T connector for
purposes of E X T T R IG oscilloscope operation. Also the
trigger generated in response to this signal.
E x te rn a l Triggering—Introducing the triggering signal
directly into the trigger circuit from an external source.
Field Effect Transistor (F E T )—A semi-conductor device
whose operation is analogous to a triode vacuum tube.
Free-Running Sweep—Continuously repetitive sweep occur-
ing independent of triggers or input signals.
Geometry—The degree to which a rectilinear display on a
CRT screen is accurately reproduced. Also the name of
the control which adjusts this quality.
Graticule—A scale associated with the cathode-ray tube
face.
Half-Power Point—The frequency at which the oscilloscope
response limits the display amplitude to 70.7% of the
actual voltage of the applied signal.
Holdoff—Sweep Holdoff.
Horizontal Am plifier—An amplifier for signals intended to
produce horizontal deflection.
H o r iz o n ta l
D eflectio n —Horizontal movement of the
cathode-ray tube electron beam away from its quiescent
or no signal position.
Horizontal Displacement—The amount of horizontal space
between electron beam quiescent position and instantan
eous position.
Horizontal Gain—The voltage ratio of output to input sig
nals associated with the Horizontal Amplifier.
Horizontal Sweep—The movement of the electron beam
from left to right across the cathode-ray tube face in
response to a changing horizontal amplifier voltage.
Input Coupling—Associated with the method of connecting
a signal into a device or circuit. Usually refers to AC or
DC coupling and signal attenuation.
Input Impedance—The combination of R, C and L which a
signal must supply with energy when the signal is applied
to the input of a circuit.
Input RC Characteristics—The value of capacitance and DC
resistance present at the input of the oscilloscope. Also
referred to as input impedance.
Internal Triggering—Using a sample of the signal present in
the vertical amplifier as a triggering signal source.
Jitter—An aberration of a repetitive display indicating
instability of the signal or of the oscilloscope. May be
random or periodic, and is usually associated with the
time axis.
Lissajous Figure—A special case of an X -Y display, pro
duced by simultaneous application of sine waves to the
vertical and horizontal deflection plates. Useful for
determining phase and frequency relationships.
Load—The impedance offered by a circuit or device. The
lower the impedance, the greater the loading effect.
Loading—Requiring a circuit to supply energy to another
circuit. The term is often associated with the effect
caused by attaching test equipment to a circuit.
Magnified Sweep—Enlarged portion of a sweep (usually
horizontal). In the Type 324 Oscilloscope the sweep can
be magnified so that 2 divisions of display are viewed
over 10 divisions through use of the X 5 H O R IZ MAG
control.
Noise—Any extraneous electrical disturbance tending to
interfere with the normal display.
Open Circuit—A discontinuous circuit.
Overshoot—In the display of a step function (usually of
time), that portion of the waveform which, immediately
following the step, exceeds its nominal or final ampli
tude.
Period—The time elapsing between occurrence of identical
points in an AC or recurring transient event. It usually
refers to repetitive waveforms and is the reciprocal of
their frequency.
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