1. Introduction of quartz crystal oscillator
Quartz crystal oscillator is composed of quartz crystal resonator, oscillatory circuit, power-on is a frequency source device with frequency signal output. The crystal oscillator produced by our company is divided into four categories: one is the ordinary crystal oscillator (called clock oscillator), the other is the temperature compensated crystal oscillator, the third is the voltage controlled temperature compensated crystal oscillator, and the fourth is the constant temperature crystal oscillator.
Clock crystal oscillator is a crystal oscillator without constant temperature control or temperature compensation. Its frequency and temperature characteristics mainly depend on the frequency and temperature characteristics of the quartz crystal resonator itself. The frequency stability in the temperature range is generally 10.-5～10-6Its characteristics are small size, light weight, low power consumption, and the frequency range is 0.4MHz to 800MHz. It is widely used in various electronic instruments, equipment, aerospace, aviation, military and other fields.
Temperature compensated crystal oscillator is an oscillator which uses temperature compensation circuit to improve the temperature characteristics of crystal oscillator. It can work in a wide temperature range and has a high frequency and temperature stability. It has the advantages of wide operating temperature range, high frequency and temperature stability, low power consumption, small size, light weight, good start-up characteristics, etc. Aerospace, aviation, program-controlled switches, general instruments and other military electronic equipment are widely used.
Voltage controlled temperature compensated crystal oscillator (VTCO) is a kind of crystal oscillator whose operating frequency varies with the control voltage. It has the advantages of high frequency stability, low single sideband noise, wide frequency modulation range, good linearity and small distortion in a wide range of linear frequency modulation. It is usually used in satellite communication and digital transmission systems.
Constant temperature crystal oscillator is an oscillator which puts quartz crystal resonator in a constant temperature tank to improve the frequency and temperature characteristics. The temperature range is wide, and the frequency temperature stability is high (less than or equal to 10).-8It has been widely used in various electronic instruments, equipment and aerospace, aviation, military and other fields.
2. Common terms of crystal oscillator
1) Frequency accuracy: The maximum allowable deviation (f-f) of the frequency of a crystal oscillator from its specified nominal value, measured at a reference temperature, as required by the specified conditions.Zero）/fZero.
2) Frequency-temperature stability: The allowable frequency offset of the maximum variation of the output frequency of a crystal oscillator relative to the sum of the extremes of the output frequency within a specified temperature range, i.e. - (f)max-fmin(f) /max+fmin)。
3) output waveform: according to the specified conditions, the output waveform of the oscillator is sine wave or square wave.
4) Frequency aging: The variation of the output frequency of a crystal oscillator with time, usually measured by the frequency difference of a certain time interval. For example, the total change from 0 to 30 days or the total frequency change within 1 years.
5) phase noise: frequency domain measurement of short-term stability. The ratio of the power of each 1Hz bandwidth to the phase noise of carrier power is represented in the single sideband spectrum.