Automatic stabilization of the oscillating circuit

A circuit in which an oscillation circuit can generate an oscillation current is called an oscillation circuit. Generally composed of components such as resistors, inductors, capacitors, and electronic devices. The lc circuit connected by the inductor 1 and the capacitor c is the simplest type of oscillation circuit, and its natural frequency is f=[sx(]1[]2πlc. § A kind of AC signal output can be generated without external excitation. Circuit. It is widely used in the field of electronic science and technology, such as the carrier oscillator of the transmitter in the communication system, the local oscillator in the receiver, the medical instrument and the signal source in the measuring instrument.
There are many types of oscillators, which are divided into sine wave oscillators and non-sinusoidal oscillators according to the waveform of the signal. The waveform generated by the sine wave oscillator is very close to a sine wave or a cosine wave, and the oscillation frequency is relatively stable; the waveform generated by the non-sinusoidal oscillator is a non-sinusoidal pulse waveform, such as a square wave, a rectangular wave, a sawtooth wave, and the like. The frequency stability of a non-sinusoidal oscillator is not high.
Among the sine wave oscillators, there are mainly LC oscillation circuits, quartz crystal oscillation circuits, and RC oscillation circuits. These circuits have the most stable frequency of the quartz crystal oscillator, the second is the LC circuit, and the RC circuit is the worst. The RC oscillator has a low operating frequency and low frequency stability, but the circuit is simple, the frequency varies widely, and is often used in low frequency bands. In communication, broadcasting, television and other equipment, the oscillator is gradually integrated. The working principle, circuit analysis and design method of these integrated sine wave oscillators are in principle consistent with the discrete component oscillation circuit. As the integration of integrated circuits is getting higher and higher, and the function of the system is developing, the internal circuits are becoming more and more complicated. If you do not start from the two aspects of system composition and unit circuit principle, it is difficult to clarify the integration of an integrated chip. The oscillator is no exception.