Definitions
Oscilátors types  Definitions 

CXO ( PXO, MXO )  Single crystal oscillator, has frequency stability of the crystal units 
VCXO  Voltage controlled crystal oscillators, can change the oscillation frequency with external voltage 
TCXO  Temperature compensated crystal oscillator, compensated for frequency changes caused by the external temperature 
OCXO  Oven control crystal oscillator, includes a temperature stabilized resonator 
Term  Unit  Definitions 

Nominal frequency f_{o} ( Output frequency ) 
[MHz]  Nominal value of the frequency described in specifications. It is the output frequency at the standard temperature (usually 25^{o}C), specified power supply voltage and load. 
Frequency stability  [ppm]  The frequency range before and after specific ambient conditions such as temperature, power supply input variations, load variations, operation time (aging, longterm stability), etc. 
Aging ( Longterm stability ) 
[ppm/year]  The frequency deviation with the lapse of time during normal operation 
Frequency stability vs. supply voltage 
[ppm/V]  Frequency deviation when the power supply input voltage is varied. 
Frequency stability vs. mechanical environment  [ppm]  Specified by the deviation before and after shock, dropping, sine wave vibration, constant acceleration, etc. applied. 
Frequency stability vs. load 
[ppm] / Z  Frequency deviation when the load conditions have varied from the standard value. 
Operation temperature range 
[ °C ]  The temperature range which the oscillator can safely operate. The frequency tolerance cannot be maintained outside the specified limits. 
Storage temperature range 
[ °C ]  Maximum absolute temperatures allowed in the discharged state. Exposure to temperatures outside these limits may result in damage. 
Supply voltage  [ V ]  The DC input voltage necessary for oscillator operation. 
Input current  [ mA ]  The amount of current consumption by an oscillator from the power supply. 
Deviation (for VCXO type) 
[ V ]  This range indicates the width of output frequency that can be adjusted by control voltage. 
StartUp time  [msec], [sec] 
The specified time from oscillator powerup to the time the oscillator reaches steady state oscillation. 
Logic levels  [ 0, 1 ]  Defined as the Output Voltage Logic High or “Logic 1” and the Output Voltage Logic Low or “Logic 0”. 
Rise time ( Tr )  [ µs ]  The time taken for the output waveform to change from the low voltage level to the high voltage level. 
Fall time ( Tf )  [ µs ]  The time taken for the output waveform to change from the high voltage level to the low voltage level. 
Duty cycle ( symmetry ) 
[ % ]  Measured at +1.4V for TTL oscillators and ½ Vdd level for universal, HCMOS and CMOS oscillators, this is the ratio of full and half cycles. 
Internal Trim  This range indicates the width of frequency that can be adjusted by a trimmer built in the oscillator. 

Phase noise  The frequency domain measure of short term frequency stability of an oscillator.  
Short term stability  The random fluctuations of the frequency of an oscillator over short periods of time. 
 Cliped Sine
C_{L} = 10 pF (including fixture and probe capacitances)
R_{L} = 10
kΩ
R_{L} = 10
kΩ
 CMOS
C_{L} = 10 pF (including fixture and probe capacitances)
 TTL
C_{L} = 15 pF max (including fixture and probe capacitances)
*T.P = Test Point
*T.P = Test Point
 Output waveform
 Phase noise
 REFLOW diagram