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Attenuation: The maximum guaranteed reduction in power, ranging
outside a specified frequency span. Spurious response attenuation is the minimum
acceptable attenuation in the stop band, which allows for unwanted modes in the
crystal.
Center Frequency or Nominal Frequency: The midpoint in the
passband.
Dew Point: The temperature at which a
condensable component of a gas starts to condense into a liquid.
Filter: A circuit or device that permits
the passage of a signal at a specific frequency while blocking the passage of
signals at other frequencies.
Frequency: The periodic repetition of an
event within a unit of time. In an electrical circuit, the number of waves that
pass a given point in one second. The number of times a resonator plate
oscillates or vibrates in one second. The nominal or desired frequency specified
by a customer.
Group Delay: The time taken for a narrow band signal to pass
from the input to the output of a device.
Group Delay Distortion: The difference between maximum and
minimum group delay in the passband.
Hertz: The basic unit of measurement of
frequency, "Hertz" replaces the term "cycle per second".
Used to denote one complete occurrence of an event.
Hz: The abbreviation of the word
"Hertz."
Insertion Loss: The loss in load power
due to the insertion of a component or device at some point in a transmission
system. (Generally expressed as the ratio in decibels of power received at the
load before insertion of the apparatus, to the power received at the load after
insertion.)
Insulator: Any of several materials that
do not easily permit the passage of electricity.
ISO: The abbreviation for
"International Organization for Standardization."
Kilo: A prefix, abbreviated
"k," used to denote units of thousands. One "Kilo" is one
thousand. In our industry, a frequency of one kilohertz is a frequency of one
thousand hertz (cycles per second).
kHz: The abbreviation for "kiloHertz,"
used to describe the frequency of a crystal or oscillator in terms of thousands
of Hertz (cycles per second). A frequency specified as "10.0 kHz"
would be understood as being a frequency of 10,000 Hertz (cycles per second). A
frequency specified as "10,000 kHz" would be understood as being a
frequency of 10,000,000 Hertz (cycles per second).
Mega: A prefix, abbreviated
"M", used to denote units of millions, 106.
One "Mega" is equal to one million. In our industry, one Megahertz is
a frequency of one million hertz (cycles per second).
milli: A prefix, abbreviated
"m", used to denote units of thousandths, 10-3.
One "milli" is equal to 1/1000th of a unit.
OEM: The abbreviation for "Original
Equipment Manufacturer."
Passband: A frequency range in which
attenuation is guaranteed to be equal to or less than a designated value in dB,
typically 3 dB.
pF: The abbreviation for "picoFarad,"
used to describe a fractional part, 10-12,
(one trillionth) of one Farad.
Pico: A prefix used to describe a
sub-multiple of a number. One pico is one trillionth, 10-12,
of a unit.
PPM: The abbreviation for "Parts
Per Million," a method of calculation used to specify the permissible
frequency deviation of a crystal or oscillator. May also be seen as "ppm."
Both are correct.
Ripple: The difference between maximum and minimum attenuation
in the passband.
Second: The basic unit of measure of
time, equivalent to "the duration of 9,192,631,770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the ground
state of the cesium-133 atom." For our purposes, one "second" is
1/60th of a minute.
Stopband: The part of the frequency spectrum that is subjected
to specified attenuation of signal strength by a filter.
Termination Impedance: The impedance that should be presented
to the source and load side of the filter to ensure proper performance.
Transition Region: The part of the spectrum between the
passband and the stopband.
Volt: The basic practical unit of
difference of (electrical) potential.
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