Frequency division and multiplication

A crystal oscillator has only one fixed frequency and can be extended to different frequencies through frequency division or multiplication.
 
(1) Frequency division: N division means that the frequency is reduced to 1/N, while the period is multiplied by N. When a quartz crystal is electrically excited, it generates a piezoelectric response and vibrates at a fixed frequency, producing a pulse signal with a voltage that varies according to a fixed period. The high-frequency signal is fed into a frequency divider, which converts it into a low-frequency signal.
 
(2) Frequency multiplication: N multiplication means that the frequency is multiplied by N, while the period is divided by 1/N. In modern communications, people require higher and more stable output frequencies. Although LC oscillators can work at higher frequencies, their stability is not high, while crystal oscillators have higher stability and accuracy, but their fundamental frequency is lower. In modern wireless communications, frequency synthesis technology (such as phase-locked loop PLL) can obtain high-stable high-frequency signals from low-frequency crystal oscillators.