AI-1
APPENDIX I
GLOSSARY
AMPLITUDE STABILITY—Amplitude stability refers to the ability of the oscillator to maintain a
constant amplitude in the output waveform.
ASTABLE MULTIVIBRATOR—A multivibrator which has no stable state. Also called free-running
because it alternates between two different output voltage levels during the time it is on. The
frequency is determined by the RC time constant of the coupling circuit.
ATTENUATION—The ability of a filter circuit to reduce the amplitude of unwanted frequencies to a
level below that of the desired output frequency.
BANDPASS FILTER—A filter which allows a narrow band of frequencies to pass through the circuit.
Rejects or attenuates frequencies which are either higher or lower than the desired band of
frequencies.
BAND-REJECT FILTER—Rejects the passage of current for a small band of frequencies. Allows
current to flow at frequencies either above or below this band.
BANDWIDTH—The range of frequencies included between upper and lower frequencies.
BISTABLE MULTIVIBRATOR—A multivibrator that has two stable states. It remains in one of the
states until a trigger is applied. It then flips to the other stable state and remains there until another
trigger is applied. Also referred to as a flip-flop.
BUFFER AMPLIFIER—An amplifier which isolates one circuit from another. It decreases the loading
effect on an oscillator by reducing the interaction between the load and the oscillator.
CAPACITIVE REACTANCE—The opposition, expressed in ohms, offered to the flow of an
alternating current by capacitance. The symbol for capacitive reactance is Xc.
CLAMPER—A circuit in which either the upper or lower extremity of a waveform is fixed at a desired
value.
COMPLEX WAVE—A waveform other than a sine wave.
COUNTER—A circuit which counts input pulses.
CRYSTAL OVEN—Closed oven maintained at a constant temperature in which a crystal and its holder
are enclosed to reduce frequency drift.
DAMPED WAVE—A sinusoidal wave in which the amplitude steadily decreases with time. Often
associated with energy loss.
FILTER CIRCUIT—Network of resistors, inductors, and/or capacitors which offers opposition to
certain frequencies.
FLYWHEEL EFFECT—The ability of a resonant circuit to operate continuously because of stored
energy or energy pulses.
