Generally speaking, whether it is a passive crystal oscillator or an active crystal oscillator, the distance between it and the chip needs to be as short as possible. The clock signal source is usually the most serious EMI (Electromagnetic Interference) radiation source in the system. If you connect a long wire, it is easy to cause the problem that the long wire becomes an antenna, which obviously will lead to prohibition in many applications, so the clock signal source must be as close as possible to the relevant components. When multiple clock signal sources are required, the method of shielding the clock connection by a multi-layer circuit board can be adopted. The output of the active crystal oscillator is generally the standard TTL specification, which can drive several chips according to the characteristics of the chip itself.