Glossary
A-D
| Affected layer | Micro cracks on layers of crystal blanks, which is caused by the lapping or cutting process. |
|---|---|
| Aging | The frequency change of the crystal operated at specific conditions for a certain period of time. |
| Aliasing Noise | A noise which does not actually exist but is created when the image sensor receives stripe patterns. It is also called a moire fringe. |
| Autoclave | A sealed vessel made from special iron, that withstands high pressure and heat. The largest size is 15 m. |
| Base-plating | A process of applying coatings of metal layers on the surface of crystal wafers. There are two main methods: vacuum deposition and sputtering. The vacuum deposition melts metals in the chambers under a vacuum state. The sputtering method occurs by bombarding the surface of the sputtering target with gaseous ions. |
| Bypass Capacitor | A component required to lower the impedance of the power-supply system. |
| Cap (Lid) | A ceramic or a metal cover, which protects the crystal blank bonded on the package. |
| Change to VOD | The difference between the pulse height of the differential output +(positive) side and the -(negative) side of the LVDS output oscillators. |
| Change to VOS | The difference of the mean of the amplitude levels of the differential output +(positive) side and -(negative) side of the LVDS output oscillators. |
| Chemical processing | A process in which the crystal blank is polished and processed with chemical solutions instead of machines. |
| CMOS | Abbreviation for Complementary Metal-Oxide Semiconductor. |
| Conductive adhesive agent | An adhesive agent which becomes electrically conductive when cured. It is used to electrically connect the crystal wafer onto the package. |
| Control Resistance (Rd) | Insertion is preferable to limit the current running to the crystal resonator and to reduce the influence of IC output impedance and load on the oscillation loop. |
| Convexing (Beveling) | The process of contouring the sides of the crystal elements to concentrate the vibration energy to its center. It is called convexing if there is no flatness in the center, and it is called beveling if there is flatness in the center. |
| Coupling Capacitance | Capacitance of the connection between elements for 4 pole filter. |
| Crystal Oscillators | An oscillator circuit that uses the characteristic vibration of a crystal resonator along with an amplifier and feedback to create an electrical signal with a very precise frequency. |
| Current Consumption | The amount of operating current used. |
| Cutoff Characteristics | characteristic in which spatial frequency (which makes moire patterns) is blocked. |
| Cylindrical type | Crystal resonators in cylindrical constructions, which are generally in kHz frequency range. |
| Depolarizer | Rays become polarized after passing through the double refraction plate. The device (phase plate) transforms such rays into non-polarized rays. It is also called a phase plate or wave plate. |
| Differential Output Voltage | Refers to the pulse height of the differential output +(positive) side and -(negative) side of LVDS output oscillators. |
| Double Refraction Plate | A filter which separates incoming ray into two separate rays: the ordinary ray and the extraordinary ray. It is also called the savart plate. |
| Drive Level | Loading condition of crystal resonator, which is determined by electric current or power applied to the crystal blank. |
E-H
| ECL | Abbreviation for Emitter Coupled Logic. It is a high speed logical integrated circuit, which operates transistors in the unsaturated zone with a -(negative) power supply. |
|---|---|
| Equivalent Circuit | The electrical equivalent circuit of a crystal resonator operating at its mechanical resonant frequency. |
| Extraordinary Ray | A light ray that changes its speed in its propagation direction when the incident light separates into two light rays through the double refraction plate. |
| Fall Time | The time interval required for the trailing edge of a waveform to change between two defined levels. |
| Feedback Resistance (Rf) | The feedback resistance for DC bias is one of the constants that determine the cut-off characteristics in the lower range of frequency. Generally, a resistance of 10 MΩ is used for oscillation in the kHz range, and a resistance of 1 MΩ is used for oscillation in the MHz range. However, if it is for overtone oscillation, a resistance of 1 kΩ may be used. |
| Frequency | The number of recurrences of a periodic phenomenon (like radio wave or acoustic wave) per one second, often measured in Hertz (Hz). |
| Frequency Adjustment Range | The output frequency range which can be shifted by the control voltage from outside to VCXOs. |
| Frequency Characteristics over Temperature (Crystal Oscillators) | Deviation from the frequency at the specified reference temperature due to operation over the specified temperature range, when other conditions remain constant. |
| Frequency Characteristics over Temperature (Crystal Resonators) | Allowable deviation of frequency at room temperature, in parts per million(×10-6). This is the maximum value within the operating temperature range. |
| Frequency Control Sensitivity | The amount of frequency that can be pulled per 1V of control voltage for VCXOs. (Unit: x10-6/V) |
| Frequency Control Voltage | The range of input voltage from the outside for shifting the frequency of VCXOs. |
| Frequency Response Slope | A term used for VCXO. VCXO's output frequency, which increase with the increment in control voltage are classified in the positive (+) polarity. On the other hand, VCXO's output frequency, which decrease with the increment in control voltage are classified in the negative (-) polarity. |
| Frequency Stability vs. Load Variation |
Deviation from the frequency at the specified load conditions due to changes in load impedance over the specified range, when other conditions remain constant. |
| Frequency Stability vs. Supply Voltage |
Deviation from the frequency at the specified supply voltage due to operation over the specified range, when other conditions remain constant. |
| Frequency Tolerance (Crystal Oscillators) |
The maximum permissible deviation of the oscillator frequency from a specified nominal value, when operating under specified condition. |
| Frequency Tolerance (Crystal Resonators) |
Allowable deviation from nominal at room temperature (25 deg.C), indicated in parts per million(×10-6). |
| Fundamental Crystal Resonators | Crystal resonator designed to oscillate in the lowest-order (fundamental) oscillation mode. |
| Guaranteed Attenuation | Relative attenuation guaranteed in a specific range within the stop band. |
| Harmonics | Unwanted frequency component, which is higher than the desired output frequency of an oscillator. |
I-L
| Infrared Absorbing Glass | A glass that absorbs infrared radiation. |
|---|---|
| Infrared Cut Coating | An optical layer that reflects infrared radiation. |
| Infrared Ray Cut-Off Filter | A filter which shuts off infrared rays. Image sensors are sensitive to infrared rays while human eyes are not so this filter is used for color correction. It is available with IR absorbing glass and IR cut coating. |
| Input Characteristics | Input conditions to control-pin for models with output control function. |
| Input Current | The current at "0" Level or "1" Level of the OE pin. |
| Input Voltage Level | The voltage condition at "0" Level or "1" Level of the OE pin. |
| Insertion Loss | Difference in attenuation when filter is inserted and not inserted. Can be either of the following: Minimum loss: Minimum value of insertion loss. Insertion loss at nominal frequency. |
| Inverse Piezoelectric Effect | The phenomenon of a piezoelectric material where certain crystals deform when they are exposed to electrical field. Lippmann predicted its presence, and P. Curie and J. Curie proved it. |
| Lapping | Lapping or polishing process of a crystal element to precisely smoothen its surface to the required frequency. |
| Lasca | Natural quartz, used as a raw material for growing synthetic quartz. |
| Length-width flexure vibration | A vibration mode where the frequency is determined by the dimensions of the crystal element. |
| Load Capacitance | The effective external capacitance that determines the resonance frequency of a crystal resonator. When this capacitance is small, the crystal resonator is vulnerable to changes in the circuit characteristics, thus deteriorating the frequency stability. |
| Load Condition | Types or the number (capacity) of loads that can be connected to the oscillator. |
| Lumbered quartz bar processing | A process which grinds the reference surfaces (crystallographic axis) of synthetic quartz bars. |
| LVDS | Abbreviation for Low Voltage Differential Signaling. It is a high speed transmission circuit of low amplitude and differential system. |
| LV-PECL | Abbreviation for Low Voltage Positive Emitter Coupled Logic. It is the power optimized version of the PECL circuit. |
M-P
| Maximum Drive Level | The maximum electric current applied to an operating crystal. |
|---|---|
| Mechanical Processing | A process in which a crystal blank is adjusted to the right shape and size by using cut wares and machine tools. Lapping is also a kind of mechanical processing. |
| MHz Band Crystal Resonators | A resonator using thickness-sheer mode and has high stability during temperature variations. |
| Moire | A noise which does not actually exist but is created when the image sensor receives stripe patterns. It is also called a aliasing noise. |
| Monolithic Crystal Filters | A device that has a frequency screening function. From a wide frequency range, it passes a specific frequency and attenuates unnecessary ones. It plays the role of extracting desired frequency in radio communications equipment such as cellular and cordless phones. With the high Q factor of the crystal, these filters feature low loss, steep attenuation characteristics and high stability as well as good temperature drifting characteristics. |
| Motional capacitance | The capacitance in the motional arm of the equivalent circuit. |
| Multiplier circuit | A circuit that multiplies the input frequency to a specific multiple frequency. |
| Natural Quartz | A mineral composed of silicon and oxygen, which has well-grown crystal faces. Amethyst and citrine is also a kind of natural quartz used for jewelry. |
| Negative Resistance | The resistance value which indicates the oscillation allowance of an oscillator circuit. It is expressed in a negative value. |
| Nominal Frequency | The specified center frequency of the crystal. |
| Non-multiplied output | The direct output of oscillators with non-multiplied circuit. |
| OCXO | A super high-precision crystal oscillator with very small frequency variations by a built-in thermostatic bath, to maintain a constant temperature of the crystal resonator. |
| Offset Voltage (Vos) | The mean of the amplitude level of the differential output +(positive) side and -(negative) side of the LVDS output oscillators. |
| Operating Temperature Range | Temperature range over which the crystal device can be operated within allowable deviation range. |
| Optical Axis | The direction of the axis when a double refraction does not occur in the birefringent crystal. |
| Optical Low Pass Filters | A filter which eliminates high frequency input through the lens structure. This reduces the aliasing noise from entering the image sensor of digital still cameras, video recorders, etc. |
| Optical Quartz Plate | Transparent substrate using a thermal conductivity characteristic of the crystal. |
| Ordinary Ray | A light ray that does not change its speed to the direction of propagation when a ray is divided into two through the double refraction plate. |
| Oscillation Allowance | The degree in ratio which indicates the oscillation allowance of an oscillator circuit. It is the same as the negative resistance. |
| Oscillation Circuit | An electronic circuit which generates a sustained current signal. |
| Output Characteristics | Standard output waveform characteristics and measurement load conditions. |
| Output Disable Time | Time lag between control-signal input and oscillation output, where oscillation output is on. Specified for models with output control function. |
| Output Enable Time | Time lag between control-signal input and oscillation output, with oscillation output switched off (no output load). Specified for models with output control function. |
| Output Frequency | Nominal value of output frequency of a crystal controlled oscillator. |
| Output Level | Amplitude of output waveform. |
| Output Load | The capacity of the oscillator to drive other devices (egs. TTL, CMOS). |
| Overtone Crystal Resonators | Crystal resonator designed to oscillate in the overtone oscillation mode (third, fifth, and seventh). |
| Overtone Order | Desired order of vibration mode, (odd) integer multiples of the fundamental mode. |
| P polarized light | An electric vector of the light wave, which oscillates parallel to the incident plane. |
| Package | A ceramic or a metal container for bonding crystal blank. The container also protects the crystal blank. |
| Parabolic Coefficient | The temperature co-efficient of a parabolic curve shown in frequency vs. temperature. |
| Pass Bandwidth | Frequency interval at which relative attenuation is guaranteed to be equal to or less than a given value. |
| Phase Jitter | The phenomenon when the phase of the pulse wave of the output signal of an oscillator moves back and forth in time from its ideal position. It is called jitter when the frequency fluctuations of the phase in time is over 10Hz. |
| Phase Noise | The generic designation of the unwanted emission of energy around the nominal frequency generated by an oscillator. |
| Phase Plate | Rays become polarized after passing through the double refraction plate. The device (phase plate) transforms such rays into non-polarized rays. It is also called a depolarizer or wave plate. |
| Piezoelectric Effect | The phenomenon of a piezoelectric material where certain crystals generate a voltage in response to applied mechanical stress. This was discovered by P. Curie and J. Curie in 1880. |
| Piezoelectric Element | An element having the properties of converting a mechanical strain (like vibration or pressure) to a charge; conversely, converts a charge to a mechanical strain. |
| Plastic-encapsulated (SMD) type | Crystal resonators encapsulated with resin. |
| PLL Output | Refers to the output of the PLL circuit based on the TCXO output signal. |
| Polarized light | An electric vector of the light wave, which vibrates in one plane. |
Q-T
| Q-factor | A value which indicates the sharpness of the peak resonance. A crystal has a small loss of vibration energy and high purity. |
|---|---|
| Reference temperature | The temperature at which certain parameters of crystal device are measured. |
| Reflection Wavefront Aberration | Deviation of the wavefront which reflected the optical system versus the wavefront of the reference surface. |
| Reflow | A soldering method which melts the solder paste being applied to the connection pads of the PCB (Printed Circuit Board) to mount electric components. |
| Reflow Temperature Profile | Specific conditions indicating the required time and temperature of the reflow oven, for mounting electric components to the PCB by reflow soldering. |
| Ripple | The maximum difference between the maximum attenuation and the minimum loss within the pass band. |
| Rise Time | The time interval required for the leading edge of a waveform to change between two defined levels. |
| RTC | A high-precision crystal application product with built-in tuning-fork crystal oscillator, has an interrupt function and data provide function necessary for calendar clock function, such as year, month, day, hour, minute and second. |
| S polarized light | An electric vector of the light wave, which oscillates perpendicular to the incident plane. |
| Savart Plate | A filter which separates incoming ray into two separate rays: the ordinary ray and the extraordinary ray. It is also called the double refraction plate. |
| Sealing | A process in which the package is tightly closed to be leak proof. This process is done under nitrogen gas atmosphere or vacuum state for the prevention of frequency stability degradation over time. There are two methods: seam-welding and glass-sealing. |
| Seed Quartz | A highly pure crystal stick or a plate used as a crystal nucleus for growing synthetic quartz bars. This crystal stick/plate serves as the seed for the recrystallization process. |
| Separation Pattern | A pattern that is formed by separating the incident light through the double refraction plate. |
| Shunt capacitance | The shunt capacitance in parallel with the motional arm of the equivalent circuit. |
| Singled Package | A package which incorporates a crystal blank and an IC in one. |
| SMD type | Abbreviation of Surface Mounted Device. It is a generic term used to identify packages which can be mounted to the PCBs. |
| Spectral Characteristics | Spectral characteristics of each wavelength. |
| Spurious | Relative attenuation produced as a result of spurious frequencies in a specific range within the stop band. |
| SPXO | An oscillator for watches, which use crystal resonance to create an electrical signal with a more precise frequency and are suitable for clock signal generators. |
| Standby Current | The current consumption, when the oscillator stops oscillating by the control voltage applied to the control pin of an oscillator having the output control function. |
| Start Up Time | The duration from the oscillation start until it reaches the specified output amplitude after power was applied. |
| Stop Bandwidth | Frequency interval at which relative attenuation is guaranteed to be equal to or more than a given value. |
| Storage Temperature Range | Temperature range, which crystal resonator should be stored at without any deterioration or damage. |
| Symmetry | The ratio between the time, in which the output voltage is above a specified level, and time in which the output voltage is below the specified level, in percent of the duration of the full signal period. |
| Synthetic quartz | A synthetic quartz bar grown by the hydrothermal crystallization method, which is used as the material for crystal devices. This high quality synthetic quartz contains practically no impurities and its shape is suitable for processing. |
| TCXO | A high-precision crystal oscillator, which has a built-in circuit that corrects frequency variations resulting from temperature variations of the crystal resonator. It is optimal for applications where small frequency tolerance is required across a wide temperature. |
| TCXO Module | Refers to TCXO modules, which have a built-in sensor and multiple output ports. |
| TCXO Output | Refers to the output signal of the TCXO modules. |
| Temperature Sensor Output | A term used for TCXO modules. Refers to the DC voltage output, which changes with temperature. |
| Terminating Impedance | Signal-source impedance or loading impedance as viewed from the filter side. |
| Thickness shear vibration | One of the vibration modes of crystal resonators where the frequency is inversely proportional to its thickness. In this vibration mode, the top and the bottom surface of the crystal blank's thickness direction moves in opposite direction from each other. This mode is called the AT-cut. |
| Tolerance in Group Delay Time | Difference between the maximum value and minimum value of the group delay time within the pass band. |
| Transmission Wavefront Aberration | Deviation of the wavefront which passed the optical system versus the wavefront of the reference surface. |
| TTL | Abbreviation for Transistor-Transistor Logic. It is a logical integrated circuit (Logic IC) consisting only of bipolar transistors. |
| Tuning Fork Crystal Resonators | A resonator with low power consumption and a tuning fork shaped crystal blank. |
| Turnover Temperature | The temperature at the peak of the parabolic curve that a crystal in kHz shows with temperature. It is expected that the crystal will have a steady oscillation if the peak temperature is within the working temperature range. |
U-Z,Other
| Ultraviolet Cut Coating | An optical layer that reflects ultraviolet radiation. |
|---|---|
| VC-TCXO | Temperature Compensated Crystal Oscillator (TCXOs) which has a function to adjust its output frequency by changing the outer voltage. |
| VCXO | A crystal oscillator, which has a variable-capacitance diode inserted into a SPXO oscillation loop, and enables the oscillation frequency to change by varying the voltage of the external power supply. The temperature characteristic of these oscillators are equivalent to those of the SPXO loop and takes advantage of the good attributes of crystal resonators. |
| Vibration Mode | One factor which determines the mechanical vibration behavior of a crystal blank is cutting angle. Examples of such vibration behaviors are thickness-sheer mode and flexure mode. |
| Wave Plate | Rays become polarized after passing through the double refraction plate. The device (phase plate) transforms such rays into non-polarized rays. It is also called a phase plate or depolarizer. |
| 0 Level Voltage | The voltage condition when the output goes into Logic ""0."" |
| 1 Level Voltage | The voltage condition when the output goes into Logic ""1."" |
| 3-state | The function where the output goes to a high impedance, when an oscillator stops oscillating by the standby function. |