18WuD2x

cross modulation • cryotron 155
they magnetize a core of nonlinear magnetic material.
Also see CROSSTALK.
cross-modulation factor An expression of the
amount of cross modulation (or crosstalk) present
in a particular instance. It is equal to M 1 /M 2 ,
where M 1 is the modulation percentage that a
modulated wave produces in a superimposed unmodulated
wave, and M 2 is the modulation percentage
of the modulated wave.
cross-neutralized circuit See CROSS-CON-
NECTED NEUTRALIZATION.
crossover 1. In a circuit diagram, a point at which
lines representing wires intersect, but are not
connected. 2. In a characteristic curve, point at
which the plot crosses an axis or operating point.
3. See CROSSOVER NETWORK.
crossover distortion Distortion of a characteristic
at a crossover point (see CROSSOVER, 2); for example,
a bend in the curve where the plot of a
waveform passes through zero.
crossover frequency The frequency at which a
crossover network delivers equal power to the two
circuits it supplies.
crossover network Following final amplification in
a sound-reproduction system, an outboard filter
circuit that facilitates delivery of the low and high
audio frequency (AF) components to the correct
speakers.
crossover point See CROSSOVER, 2.
crossover S-curve The S-shaped image obtained
on an oscilloscope screen during sweep-generator
alignment of a frequency-modulation (FM) detector.
In correct alignment, the exact center of the
S-curve (the crossover point) coincides with the
zero point on the screen.
cross product Also called vector product. For vectors
A and B having lengths A and B, respectively,
and subtending an angle θ relative to each other,
the cross product A × B points in a direction perpendicular
to the plane containing both A and B.
The length of A × B is equal to AB sin θ.
z
A
y
θ
A × B
B
cross product
x
cross-sectional area 1. The surface area of a face
of a conductor after cutting through it at a right
angle. Specified in square inches, square millimeters,
or circular mils. 2. The total of the crosssectional
areas of all the wires in a stranded
conductor.
cross-sectional testing In quality assurance and
quality control (QA/QC), a method of checking a
large lot of units or components. Instead of testing
every device, a fraction of the devices is
tested. The sampling is taken uniformly from the
group (e.g., every fifth unit).
crosstalk Undesired transfer of signals between or
among telephone lines, data lines, or system
components. In computer operations, this effect
places a practical limit on the lengths of parallel
data cables.
crosstalk coupling Undesired coupling between
circuits, caused by crosstalk.
crosstalk factor See CROSS-MODULATION FAC-
TOR.
crosstalk level The amplitude of crosstalk, usually
expressed in decibels above a reference level.
crosstalk loss Loss of energy caused by crosstalk.
crowbar An action producing a high overload on a
circuit protection device.
crowfoot 1. A pattern formed by the cracking or
crazing of solid plastics of solidified encapsulating
compounds, so called from its resemblance to
a bird’s footprint. 2. In a gravity battery cell, the
zinc electrode, so called from its resemblance to a
bird’s foot.
CRT Abbreviation of CATHODE-RAY TUBE.
crud 1. Broadband electrical noise, originating inside
and/or outside a system. 2. Undesired signals
that interfere with a desired signal.
cryogenic device A device that exhibits unique
electrical characteristics (such as superconductivity)
at extremely low temperatures.
cryogenic motor A motor designed for operation
at extremely low temperatures.
cryoelectronics The study of the behavior of electronic
devices, circuits, and systems at extremely
low temperatures.
cryogenics The branch of physics dealing with the
behavior of matter at temperatures approaching
absolute zero. Also concerned with methods of
obtaining such temperatures in controlled environments.
cryosar A semiconductor switch utilizing lowtemperature
avalanche breakdown.
cryoscope An instrument used to determine freezing
point.
cryostat A chamber for maintaining a very low
temperature for cryogenic operations. Also see
CRYOGENICS.
cryotron A switching device consisting essentially
of a straight tantalum wire, around which a
single-layer control coil is wound. The magnetic
field generated by control current flowing through
the coil causes the tantalum wire to become