Question

What are the two requirements for oscillation?

Answer 1

Let us first know about oscillators. An oscillator is an electrical device that generates the voltage of an AC signal. From very low frequencies to very high frequencies, oscillators generate sinusoidal or non-sinusoidal waveforms. Most modern broadcast band AM superheterodyne have a local oscillator that covers a frequency range of $1000{\text{ }}to{\text{ }}2100{\text{ }}KHz$(approximately).

Complete step-by-step solution:
An oscillator circuit is just an amplifier that provides itself with an input signal (through feedback). It is a nonrotating device that produces alternating current, with the output frequency defined by the device's properties. An Oscillator's primary function is to generate a waveform with a consistent peak amplitude and precise frequency and to keep it within predefined amplitude and frequency constraints.

Two Oscillation Requirements:
1. To produce the signal with the required gain, the oscillator requires amplification.
2. The oscillator needs enough regeneration feedback to keep oscillations going.
The following two types of electronic oscillators can be generally classified.
The oscillators that produce a sine wave output are known as sinusoidal or harmonic oscillators. The output frequency of such oscillators can range from $20$ Hz to GHz.
Non-sinusoidal or relaxation oscillators are oscillators that produce a square, rectangular, or saw tooth waveform as an output. Oscillators of this type can provide output at frequencies ranging from $0{\text{ }}to{\text{ }}20$Mhz.

Note: An oscillator's frequency stability is a measure of its ability to keep a consistent frequency over a lengthy period of time. However, it has been discovered that if an oscillator is tuned to a specific frequency, it does not retain that frequency for a long time.