• Technical support
Crystal Oscillators

1, Frequency accuracy: the required conditions, the output frequency crystal relative to allow deviation from the nominal frequency value. Usually use the relative value to express.
2, Frequency stability:
2.1 [time domain characterization]
⑴ Specified conditions, the crystal internal components due to aging caused output frequency drift with time. Usually used within a certain time interval of the frequency difference aging relative value to measure (eg, months or years of aging rate, etc.).
⑵ Stability (or the fluctuations): Refers to the crystal output frequency within 24 hours of changes. Usually use greatest change of the relative value to express.
2.2 [frequency domain characterization]
 ⑴ unilateral phase noise power spectral density, crystal spectrum of the output signal with the frequency f Hz deviated from the set every Hz bandwidth in the unilateral power and phase noise signal power ratio of decibels (dB) volume, Writing
£ (f) units dB / Hz.
⑵ Spectrum purity: Crystal Oscillator is a measure of internal noise and spurious spectral standards. Usually use unilateral noise power spectral density to express.
3, Output waveforms: sine wave and a square wave two.
4, Output rate: access provisions rated load conditions, the root-mean-square value of crystal output voltage.
5, Frequency temperature characteristics: When the temperature in the environment according to the provisions of the way changes, the output frequency crystal relative changes in the characteristics.
6, Voltage-controlled linearity: that the output frequency and voltage-controlled crystal curve deviated from the linear voltage-controlled voltage level.

•Application Guide
According to the different crystal use requirements and characteristics, usually divided into the following categories: general crystal, crystal Warming, voltage - controlled crystal oscillator, temperature control, such as crystal. Installation crystal, should function under its logo pin should be connected with the application circuit to avoid power wire connecting with the output pin output.
When used in the testing and for DC power supply should not affect the accuracy of its ripple content, the exchange should be no transient voltage process. Testing equipment should provide sufficient accuracy and connectivity reasonable layout, testing and the external circuit indicator of crystal to minimize the impact.
1, Ordinary crystal (PXO): a temperature compensation measures did not take the crystal oscillator, in the whole temperature range, the crystal frequency stability depends on its internal crystal used in the performance, frequency stability in the order of 10-5, commonly used for ordinary places or as a Local Oscillator middle signal is the most inexpensive crystal products.
2, Prescription for warming crystal oscillators (TCXO): in the crystal is taken on the internal temperature of crystal frequency compensation to meet wide temperature range temperature range to meet the requirements of stability crystal oscillator. General analogue Warming crystal used thermal compensation network. Compensation frequency stability in the order of 10E7 to 10E6, due to its characteristics of a good boot, excellent cost performance and low power consumption, small size, strong environmental adaptability, and many advantages, which will be widely used.
3, Voltage-controlled crystal oscillator (VCXO): is an applied voltage can be adjusted so that crystal output frequency of the crystal oscillator changed, or mainly used for PLL frequency tuning. The voltage-controlled crystal oscillator frequency control range and linearity mainly determined by the circuit and used varactor diode combination of the two crystal parameters.
4, Thermostats crystal (OCXO): using precision temperature control so that the circuit elements working in the Crystal and Crystal zero temperature coefficient points on the temperature. Precision products in the frequency stability of 10E7 to 10E8, high-precision products frequency stability in the order of magnitude more than 10E9. Mainly used as a frequency source or standard letter

Copyright: Beijing Candor Electronics Co., Ltd.
Add:No.16, Yumin Street, Area B, Tianzhu Airport Industrial Zone,Beijing, P.R.China  Postcode: 101318  Fax: +86-10-80483125
Tel: +86-10-80483105 (Ext.104, 105,107,113,118) E-mail: sale@mail.candor-co.com