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Brilliant brace up fundamental and character
From;  Author:Stand originally
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Brilliant brace up the electric capacity that uses the 1a that be like a graph commonly 3 end type (take an examination of Bi Ci) communicate equivalent oscillating circuit; Actual brilliant brace up communicate equivalent circuit to be like graph 1b, among them Cv is to be used adjust oscillation frequency, add those who differ to slant instead with transfiguration diode commonly voltage will come true, this also is to press the mechanism that controls function; Graph 1c is like after the equivalent circuit crystal replaces crystal. Among them Co, c1, l1, RR is the equivalent circuit of crystal.



The analysis is whole oscillation chamfer road is knowable, using Cv to change frequency is finite: Decide the C=Cbe of capacitance of whole chamfer road of oscillation frequency, cce, cv3 after capacitance establishs ties, mix again with Co paralell connection C1 series connection. Can see: C1 is smaller, co is bigger, the to capacitance of whole chamfer road effect when Cv changes is less. Consequently can " pressure accuse " frequency scope is less also. Actually, because C1 is very small (1E-15 measures class) , co cannot oversight (1E-12 measures level, a few PF) . So, when Cv greatens, the effect that reduces groovy road frequency is less and less, when Cv decrescent, the effect of frequency of elevatory chamfer road is bigger and bigger however. This is caused on one hand pressure those who accuse character is nonlinear, pressure accuse limits bigger, nonlinear fiercer; On the other hand, the feedback voltage of deal out oscillation (the voltage on Cbe) smaller and smaller however, bring about finally stop brace up.

Use overtone frequency to jump over tall brilliant brace up, c1 of its equivalent capacitance is smaller; The span of frequency is accordingly smaller also.

Brilliant brace up index

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 error of frequency.

Explain: The character of voltage of the deviation that total frequency difference includes rate of ageing of frequency temperature stability, frequency to cause, frequency and frequency load performance the biggest frequency difference that 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 stability: Any brilliant brace up, it is absolutely that frequency is not stabilized, level is different just. A brilliant brace up if the curve that output frequency changes along with time pursues 2. 3 kinds of elements with not stable frequency show in the graph: Ageing, drift and short firm.
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