Crystal resonator (DIP) is also called in-line passive crystal oscillator, which needs to use digital signal to process the oscillator in DSP chip; passive crystal oscillator has no voltage, and the signal level is variable, that is to say, it is based on the oscillation circuit. decided. The same crystal can be applied to a variety of voltages, and can be used for DSPs with different clock signal voltage requirements, and the price is usually lower. Passive crystal oscillators usually need to accurately match the peripheral circuits (capacitors, inductors, resistors, etc. for signal matching), and the peripheral configuration circuits need to be adjusted accordingly when replacing crystals with different frequencies.