Glossary of Oscillator Terms
Glossary of Oscillator Terms
Aging
A systematic average change of an oscillators output frequency as a function only of time. Aging does not include effects of changing environments
Calibration or Adjustment Tolerance
The setting tolerance is the maximum allowable deviation from the nominal frequency at 25°C +- 3°C. It is normally specified in parts per million (ppm)
Duty Cycle
The percentage of each period that a signal is in logic high. This parameter is measured at a specified voltage treshold or at a percentage of the output waveform amplitude
Fall Time
The waveform fall time from high to low transition
Input Current
The amount of current consumption by an oscillator from the power supply, typically
specified in milliamperes (mA)
Jitter
The modulation in phase or frequency of the clock oscillator output
Linearity
The departure from a straight-line relationship of control voltage to output frequency
Load (fan out)
The capacity of the oscillator to drive other devices
Nominal Frequency
The nominal frequency of the oscillator is expressed in Megahertz ( Mhz) for frequencies of 1.0 Mhz and over. Frequencies may be specified to seven significant figures. If less are specified, then we may assume any digits that follow are zero
Operating Temperature Range
This is the temperature range over wich the quoted temperature stability is specified
Output
The output of a hybrid crystal clock oscillator is a highly stable reference signal
Phase noise
The ratio of the power density of one phase modulation sideband to the total signal. It is usually specified as the single side band (SSB) power density in a 1Hz bandwidth at a specified offset frequency from the carrier. It is measured in dBc/Hz
Pullability
The frequency shift of a VCXO as a function of control voltage
Rise Time
The rise time of an oscillator is defined as the transition
time of the output wave form from a low to a high state. The transition time
is measured between 90% and 10% of the falling edge of the switching wave form
for TTL and CMOS devices
Start-up Time
The period from the instant voltage is applied to the oscillator until the oscillator output is stabilized
Storage Temperature Range
The temperature range in which the oscillator can be stored without damage, i.e. it will resume operation as normal once it is restored to within its operable temperature range
Temperature Stability
Deviation from the nominal frequency including the frequency deviations due to manufacturing process, temperature, power source variation and load variation
Tristate
The tristate function allows the oscillator to be isolated from the circuit
upon application of a command signal. When this feature is activated, the output
of the oscillator is in tristate mode. The tristate mode allows the customer
to remove the oscillator from their circuit without physically removing it.
Useful for tuning, testing or trouble shooting their board