In a nutshell, a passive crystal oscillator is a non-polar electronic component that cannot oscillate itself, and requires a clock circuit to generate an oscillating signal. But an active crystal ...

Inside the insulated enclosure there is of course the crystal oscillator itself, which has a heating coil wrapped around it.

Research from all publishers Recent investigations into low-power crystal oscillator design have demonstrated significant progress in both performance and integration.

The GPSDO takes the precision 1 Pulse-Per-Second (PPS) GPS signal and uses it to adjust the 10 MHz crystal oscillator until it repeatedly produces 10,000,000 cycles within one second.