18WuD2x

610 scale expansion • scanning yoke
scale expansion Spreading out the divisions in
part of a scale (see SCALE, 1).
scale factor 1. A figure by which the readings from
a particular scale must be multiplied or divided to
give the true values of measured quantities. 2. A
figure via which values in one system of notation
are converted to those in another system. 3. In
scaling down (see SCALE DOWN), the factor by
which a group of quantities is adjusted. 4. The
ratio of output frequency to input voltage for a
voltage-to-frequency converter.
scale-factor adjustment In some meters, an adjustment
that allows full-scale deflection to be set
at any desired value (within certain limits) of applied-signal
amplitude.
scale-factor error The absolute value of the difference
between the actual scale factor and the ideal
scale factor for a multiplier circuit.
scale-factor tolerance The extent to which a measured
value for the scale factor differs from the
computed value. It is generally given as a percentage.
scale length The end-to-end dimension of a scale
(see SCALE, 1), in inches, centimeters, geometric
degrees, or number of divisions.
scale multiplier See SCALE FACTOR, 1.
scale-of-two counter A circuit that delivers one
output pulse for two successive input pulses.
scale-of-10 counter A circuit that delivers one
output pulse for 10 successive input pulses.
scale-of-ten scaler See SCALE-OF-10 COUNTER.
scaler A circuit or device for extending the frequency
range of another device (e.g., a circuit that
extends the range of a 1-MHz counter to 100
MHz).
scale range The difference between the lowest and
highest values on a scale.
scale span See SCALE RANGE.
scaling The fact, and the implications of the fact,
that the mechanical strength of a structure increases
in proportion to the square of linear dimension
while the weight increases, according to
the cube of linear dimension. Thus, weight increases
more rapidly than strength as a structure,
composed of a given material, is made
larger. It is important in the design of large antennas
and support structures.
scaling adder An inverting OPERATIONAL AMPLI-
FIER used to weight and sum multiple voltages.
scaling circuit A circuit, such as one or more flipflops,
that will deliver one output pulse after a
predetermined number of input pulses have been
received; therefore, it will provide pulse or frequency
division. See, for example, SCALE-OF-
TWO COUNTER.
scaling factor For a scaler, the number of input
pulses required for one output pulse.
scaling ratio See SCALING FACTOR.
scan 1. To traverse a range, field, or dimension.
2. The amount of traversal in 1. 3. See SWEEP.
4. To sample or reproduce an image in a single-line
element, as in facsimile or television. 5. A single
line resulting from 4. 6. In information retrieval
operations, to inspect each record in a file or constituent
of a list. 7. To check communications or
data channels for availability.
scan conversion In television reception, the scanning
of each line twice to convert a conventional
image into one that can be displayed on a highdefinition
picture tube.
scan-converter tube A face-to-face assembly of a
cathode-ray tube and a vidicon in one envelope.
scandium Symbol, Sc. A metallic element. Atomic
number, 21. Atomic weight, 44.956.
scan frequency See SCANNING FREQUENCY.
scanner A device, especially a radio receiver,
equipped with a circuit that searches communications
or data channels for signals.
scanner amplifier An amplifier for boosting a
scanning signal. Also see SCAN, 1, 3, 4.
scanning 1. In a cathode-ray tube or camera tube,
the synchronized movement of the electron beam
(or other marker) from right to left and/or from
top to bottom. 2. The intermittent, but repetitive,
monitoring of two or more communications channels
in rotating sequence. 3. The movement of a
radar beam for the purpose of obtaining coverage
over a specified area.
scanning antenna A transmitting or receiving antenna
(such as a rotating one) that covers a generally
circular region.
scanning beam The deflected electron beam in a
cathode-ray tube. Also see SCAN, 1, 2, 3, 4, 5.
scanning circuit A circuit for producing a scan
(see SCAN, 2, 4).
scanning frequency The number of scans per unit
time, usually expressed in lines, sweeps, or channels
per second or per minute. Also called SCAN-
NING RATE.
scanning line A single line sampled or produced
by a scanning process, as in facsimile, television,
and graphic recording.
scanning line frequency See SCANNING FRE-
QUENCY.
scanning linearity Uniformity of scanning rate. In
a linear scan, for example, scan speed is the same
at all points along a line.
scanning loss The effective reduction in radar sensitivity
that occurs as the beam scans a given
area, rather than remaining in a fixed orientation.
scanning rate See SCANNING FREQUENCY.
scanning receiver A receiver whose tuning is automatically
and continuously swept through a
frequency band to detect all signals in the band.
scanning sonar A form of distance-measuring or
depth-finding sonar, in which the receiving transducer
scans to find the direction of the echo or
echoes.
scanning speed The rate at which a line, region, or
quantity is scanned or at which samples are
taken.
scanning yoke See YOKE, 2.