Tech Info - Crystals
Tech Info - Oscillators
Tech Info - Filters

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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