The characteristic is similar to the initial factory aging characteristic, but high stability is achieved significantly more quickly because the crystal has been factory pre-aged. In most applications, oven-controlled crystal oscillators are continuously energized. When applications require frequent turn-off, an additional series of characteristics should be considered. This is called the retrace characteristic. This is called the restabilization, or warmup, characteristic.
Many factors affect retrace, restabilization and reaging characteristics.
These characteristics are of little consequence in oscillators which are energized continuously. While most high stability crystal oscillators use AT Cut Crystals, SC and IT Cut Crystals are often used in the highest stability models. Others in the family include the IT Cut and FC Cut. The SC Cut represents the optimum double rotated design as its particular angle provides maximum stress compensation, but similar performance is achieved with the IT Cut. Phase Noise .