Basic knowledge of crystal oscillator

1. Concept
The electrical equivalent of a capacitor and a resistor in parallel in tandem with a capacitor two-terminal network, there are two resonant points, the lower frequency is series resonance, the higher the frequency is the parallel resonance.
These two frequencies close, and then very narrow frequency range, the crystal is equivalent to an inductor, as long as the two ends of the crystal oscillator in parallel to the appropriate capacitance can be composed of parallel resonant circuit.

2, choose the parallel capacitance with the load capacitance value, you can get the crystal oscillator nominal resonant frequency;

3. Classification: Passive crystal (crystal), active crystal oscillator (oscillator, oscillator);

4, Oscillation principle: piezoelectric effect;

5. Piezoelectric resonance: When the frequency of the alternating voltage is equal to the natural frequency of the wafer (determined by the size of the wafer), the amplitude of mechanical vibration increases sharply;

6, quartz crystal oscillator is the use of the piezoelectric effect of quartz crystals to start the vibration, quartz crystal resonator is the use of quartz crystals and built-in IC to work together;
The oscillator is used directly in the circuit, and the work of the resonator is generally required to provide a voltage of 3.3V to maintain the work.
The oscillator has an important technical parameter more than the resonator: the resonant resistor (RR);

7, Q value: The main parameters of the measurement of inductance, refers to the inductor and a certain frequency of AC work, the inductance and equivalent loss of resistance ratio.
The higher the Q value, the lower the loss and the higher the efficiency.

Address register (Adress Register,ar): Used to save the address of the memory unit accessed by the current CPU;

Basic knowledge of crystal oscillator