----The article introduced a few enough to show the technical index of discretion of function of oscillator of a crystal, understand the implication of these index, will conduce to communication designing an engineer to complete design project smoothly, also can decrease greatly at the same time overall of manufacturer home purchase cost.
----Total frequency difference: Inside formulary time, the job as a result of the regulation and the crystal oscillator frequency that are not the job to parameter is combined entirely and be caused and give nominal the biggest frequency difference of frequency.
----Explain: Total frequency difference includes stability of voltage of power source of rate of ageing of accuracy of temperature of frequency temperature stability, frequency, frequency, frequency and frequency the biggest frequency difference that laden stability creates jointly. Caring to short-term frequency stability only commonly, and the circumstance of not strict to index of other frequency stability requirement is used. For example: Radar of accurate control and guide.
----Frequency temperature stability: Be in nominal below power source and load, the job inside formulary temperature limits what do not take implicit and fiducial temperature or take implicit and fiducial temperature is the biggest allow frequency to slant.
----FT= ± (Fmax-fmin)/(fmax Fmin)
----｜ of MAX[of FTref ＝ ± (Fmax-fref)/fref ｜ , ｜ (Fmin-fref)/fref ｜ ] FT: Frequency temperature stability (not the belt is implicit and fiducial temperature)
----FTref: Frequency temperature stability (take implicit and fiducial temperature)
----Fmax: The highest frequency that measures inside formulary temperature limits
----Fmin: The lowermost frequency that measures inside formulary temperature limits
----Fref: The frequency that sets fiducial temperature to be measured
----Explain: Its produce the crystal oscillator that uses FTref index the crystal oscillator that difficulty wants prep above to use FT index, the crystal oscillator price of reason FTref index is higher.
----Index of frequency temperature stability sees the crystal oscillator model that system of a few kinds of electrons uses next watches:
----There is index of stability of temperature of one part frequency in the watch should be the index of frequency temperature stability that brings implicit and fiducial temperature, but did not express. (1ppm=1 × 10-6; 1ppb=1 × 10-9) .
----Frequency stabilizes warm-up time: With crystal oscillator stable output frequency is fiducial, from the time that increases report to output frequency to be less than formulary frequency allow to differ a need.
----Explain: In majority application, crystal oscillator appends report for a long time, switch on the mobile phone often in need of oscillator of the crystal in certain applying however and close machine, at this moment need of index of time of frequency stability warm-up is considered (the broadcasting station of communication of for military use that uses in harsh to be in environment especially, when stability of requirement frequency temperature 85 ℃ of ～ of ℃ of ≤ ± 0.3ppm(-45) , use OCXO to regard as this brace up, frequency stabilizes warm-up time will not less than 5 minutes, and use DTCXO to need) ten seconds only.
Previous12 Next