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Aging: A change in the frequency and/or the resistance of
a quartz crystal unit with the passage of time.
CMOS: The abbreviation for "Complementary Metal Oxide Semiconductor."
Control Voltage: The range of voltage used to pull the frequency.
Cycle: One complete repetition of an event.
Deviation: The amount by which a quantity differs from its nominal value.
For our purposes, the amount by which a frequency differs
from the nominal or specified frequency.
Dew Point: The temperature at which a condensible component of
a gas starts to condense into a liquid.
ECL: The abbreviation for "Emitter Coupled Logic."
Enable/Disable
Function: A control function that enables or disables
the output of the oscillator. When the oscillator is in its
disabled state, the oscillator is still running internally,
but no output is coming from the output pin.
Enable/Disable
Time: The time between application of the proper voltage
to the enable/disable pin and the moment the output becomes
enabled or disabled.
Extended Temperature
Range: An option available on selected oscillators.
Extended temperature range is -40°C to +85°C.
Fall
Time: The amount of time it takes the output voltage
to go from Logic ‘1’ to logic ‘0’.
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.
Hertz: The basic unit of measurement of frequency, "Hertz"
replaces the term "cycle per second". Used to denote
one complete occurrence of an event in one second.
Hz: The abbreviation of the word "Hertz."
Holder: The
complete housing for a quartz resonator plate. The holder
includes the base and cover.
Impedance: The total opposition presented by a circuit or device to the
flow of alternating current. Impedance is measured in "ohms"
and is represented by the letter "Z."
Input Current: The amount of current consumed by the oscillator.
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).
Linearity: The uniformity of the shift in frequency over voltage
change, when pulling the frequency of a VCXO.
Load Impedance: The impedance presented by a load connected to a generator
or other source.
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."
Oscillator: A circuit or device that produces an alternating
current of a specific frequency at its output terminals.
Output Current: Is represented by IOL and IOH, which is the output current
at VOL and VOH.
Output Load
(Fan out): The capacity of the oscillator to drive
other devices. TTL devices are specified in the number of
gates that can be driven; i.e., 10 TTL gates. CMOS outputs
are specified in picoFarads (pF); i.e., 15pF or 50pF loads.
Output Voltage: Is represented by VOL, which is the maximum voltage that output
low will be and VOH which is the minimum voltage that output
high will be.
Overlap Time: The time, measured at 50% Vp-p, at which the two outputs
of a complementary output ECL oscillator overlap.
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.
Pin Through: Refers to a package with leads. When the device is mounted
on a PCB, the leads go through the board.
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.
Pullability: The amount the frequency can be made to deviate by varying
the voltage on the control pin.
Resistor: A component used to introduce resistance into a circuit.
Rise Time: The amount of time it takes the output voltage to go from
Logic ‘0’ to logic ‘1’.
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.
Sine wave: A periodic wave that can be represented by a sine curve. The
amplitude of such a wave is a function of the sine of a linear
quantity such as phase or time.
SMD: The abbreviation for "Surface Mount Device."
Square Wave: An alternating or pulsating current or voltage whose wave
shape is square.
Stability: The maximum amount of frequency deviation of the oscillator.
Stability includes the tolerance at 25? C; drift over operating
temperature range; changes in input voltage; changes in load,
shock, vibration; and aging.
Standby Current: Amount of current consumed by the oscillator when it is in
its standby mode.
Standby Function: A control function similar to the Enable/Disable function.
In this case, the oscillator actually stops oscillating. This
type of oscillator draws less current than an Enable/Disable
type oscillator (when both are in their disabled states).
Start-up Time: The period from the instant voltage is applied to the oscillator
until the oscillator output is stabilized.
Supply Voltage: Voltage required for the oscillator to operate within specification.
Surface Mount: Refers to a package with pads that mount to the surface of
the PCB.
Symmetry: A measure of the uniformity of the output waveform.
T.C.X.O: The abbreviation for "Temperature Compensated Crystal
Oscillator." Such an oscillator contains a temperature
sensing network that adjusts the output frequency, thereby
allowing the frequency to remain constant over a specified
temperature range.
Tri-state: The ability to turn the output on or off using pin one for
control. The output will go to a high impedance when disabled,
which facilitates the use of Auto Test Equipment (ATE). Note:
Tri-state may be substituted for non-tri-state if pin #1 is
left open or held high.
TTL: The abbreviation for "Transistor-Transistor Logic."
V.C.X.O: The abbreviation for "Voltage Controlled Crystal Oscillator."
Such an oscillator contains a network that employs changes
in voltage to change the output frequency.
Volt: The basic practical unit of difference of (electrical) potential.
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specifications subject to change * revision 3-2003
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