Glossary / Definition of Terms
(Crystals and Oscillators)

Crystal Cut - The orientation of the crystal element with respect to crystallographic axis of the crystal.

Crystal Element - Piezoelectric material cut to a given geometric shape, size and orientation with respect to the crystallographic axis of the crystal.

Electrode - An electrically conductive film in contact with the face of the crystal element, by means of which an electric field is applied to the element.

Crystal Enclosure - The enclosure protecting the crystal vibrator(s) and mounting system.

Crystal Unit Equivalent Circuit - The electrical circuit which has the same impedance as the unit in the immediate neighborhood of resonance.

Load Capacitance (CL) - The effective external capacitance associated with the crystal unit which determines the load resonance frequency (fL).

Nominal Frequency - The frequency assigned by the specification of the crystal unit.

Resonance Frequency (fr) - The lower of two frequencies of the crystal unit alone, under specified conditions, at which the electrical impedance of the crystal unit is resistive.

Resonance Resistance (Rr, R1) - The resistance of the crystal unit alone at the resonance frequency.

Load Resonance Resistance (RL) - The resistance of the crystal unit in series with a stated external capacitance at the load resonance frequency.

Motional Inductance (L1) - The inductance in the motional (series) arm of the equivalent circuit.

Motional Capacitance - The capacitance of the motional (series) arm of the equivalent circuit.

Shunt Capacitance (C0) - The static capacitance between the electrodes, together with stray capacitances of the mounting system.

Capacitance Ratio (C0/C1) - The ratio of the shunt capacitance to the motional capacitance.

Overtone Order - The numbers allotted to the successive overtones of a given mode of vibration from the integral numbers commencing with the fundamental as unity.

Unwanted Response - Frequency responses other than the main, or desired response, which the crystal elements have.

Frequency Tolerance - The permissible deviation from the nominal frequency at the reference temperature ( usually 25C ).

Operating Temperature Range - The range of temperatures over which the crystal unit shall function within the specified tolerances.

Storage Temperature Range - The temperature range over which the standard characteristics of the crystal unit can be maintained when the crystal unit is not in operation.

Drive Level, (Level of Drive) - The level of power or current in the crystal unit when in the operating state.

Aging - The relation which exists between any parameter (e.g. resonance frequency) and time.

Insulation Resistance - Resistance between leads, or between lead and case.

Q Value - In a resonance circuit composed of an L, C, and R, a quantity that represents the sharpness of a resonance curve-a curve that shows the relationship between the circuit current and power frequency.

Frequency Stability - Within operating temperature, operating voltage and output load range, deviation in actual frequency from nominal frequency.

Supply Current - The electric current to supply (VDD) pin with no output load when output is enabled.

Duty - The 1/2 cycle to 1 cycle ratio ( as expressed in percentages) of an output waveform at the specified voltage level.

Output Load - The load that can be connected to the oscillator.

Rise Time - The time interval required for the leading edge of a pulse wave form to change from specified L voltage level to specified L voltage level.

Fall Time - The time interval between power on and supply voltage becomes the specified voltage until the output waveform becomes stable.

Output Enable Function - The function to change the output signal.

When pins OE are at H level or open: Specified frequency is output.(Enable)

When pins OE are at L level : Output has high impedance. (Disable)

Disable Current - The electric current to supply(VDD) pin when output is disabled.