18WuD2x

efractivity • rejection filter 591
velocity in free space, and v 2 is the phase velocity
in the medium through which a wave passes.
refractory A heat-resistant, nonmetallic ceramic
material.
refrigerator A chamber used to maintain a circuit
or component at a constant temperature that is
lower than the ambient temperature. This device
is analogous to the oven, which maintains a
higher temperature than the surrounding
medium. A refrigerator can be used to maintain
precise frequency for a reference oscillator.
regeneration 1. The processing of a distorted signal
so that it has its original characteristics.
2. Positive feedback generally used for the purpose
of causing oscillation, or for detection in a regenerative
receiver. See POSITIVE FEEDBACK.
regeneration period The period during which the
electron beam scans a cathode-ray tube screen to
restore changes to the screen surface.
regenerative amplifier An amplifier that uses regeneration
to increase its gain and/or selectivity.
regenerative detector A detector provided with regenerative
feedback. Although such a detector is
sensitive, it can be unstable. Compare NONRE-
GENERATIVE DETECTOR.
regenerative feedback Feedback producing regeneration
(i.e., positive feedback). Compare DE-
GENERATIVE FEEDBACK.
regenerative IF amplifier An intermediatefrequency
amplifier in which regeneration is introduced
to boost sensitivity and, sometimes,
selectivity.
regenerative reading A method of reading data
(see READ) so that it is automatically restored, by
writing, to locations from which it came.
register In computer systems, an arrangement of
several storage devices, such as flip-flops, for
storing a certain number of digits (a two-bit register,
for example, requires two flip-flops).
register capacity The range of values for quantities
that can be handled by a register.
registered professional engineer A title granted
by a state board of examiners to a person licensed
to work as an engineer.
register length The number of characters or bits
that can be held in a register, according to its capacity.
registration The accurate alignment of terminals
or other points on different components or on opposite
sides of a board so that when the surfaces
containing those points are overlaid, all points
mate precisely.
regulated power supply A power supply whose
output is held automatically to a constant level or
within a narrow range, regardless of loading variations.
regulating transformer See VOLTAGE-REGULAT-
ING TRANSFORMER.
regulation 1. In general, the adjustment or control
of a component, device, or system. 2. Automatic
control. See, for example, SELF-REGULATION.
3. See CURRENT REGULATION. 4. See VOLT-
AGE REGULATION.
regulator 1. A device that automatically holds a
quantity to a constant value (e.g., a voltage regulator).
2. A device via which a quantity can be varied
(e.g., potentiometer, rheostat, and variable
autotransformer).
regulator diode A semiconductor diode—especially
a Zener diode used as a two-terminal voltage
regulator.
reinitialization The setting of all lines in a microcomputer
or microprocessor to logic zero automatically
when power is removed, then reapplied.
reject amplifier A tuned amplifier having the response
of a band-suppression filter. Like the filter,
the amplifier rejects or severely attenuates
one frequency (or band of frequencies) while readily
passing lower and higher frequencies. Compare
PASS AMPLIFIER.
reject filter See REJECTION FILTER.
rejection circuit A circuit performing the function
of a REJECTION FILTER.
rejection filter A filter that suppresses one frequency
(or band of frequencies) while passing all
other frequencies.
Input
rejection filter
Output