CN203661009U - Circuit improving crystal oscillator resonance frequency - Google Patents

Abstract

The utility model discloses a circuit improving crystal oscillator resonance frequency. The circuit selects different resonance capacitors according to different distances between a crystal oscillator and a used module. The magnitude of a resonance capacitor C1 which is connected with a first pin of the crystal oscillator is C1=1/f<2>2pi<2>L1, wherein C1 is the magnitude of the resonance capacitor C1, f is the magnitude of the frequency of the crystal oscillator, and L1 is the distance from the first pin of the crystal oscillator X1 to the used module. The magnitude of a resonance capacitor C2 which is connected with a second pin of the crystal oscillator is C2=1/f<2>2pi<2>L2, wherein C2 is the magnitude of the resonance capacitor C2, f is the magnitude of the frequency of the crystal oscillator, and L2 is the distance from the second pin of the crystal oscillator X1 to the used module. According to the utility model, the capacitor values of two resonance capacitors are designed to different values; the problem that a crystal oscillator theoretical value and the actual use frequency are different is solved; and the true use frequency value is close to the theoretical value to the greatest extent.

Description

A kind of circuit that improves crystal oscillator resonance frequency

Technical field

The utility model discloses a kind of circuit, particularly a kind of circuit that improves crystal oscillator resonance frequency.

Background technology

Crystal oscillator is called again quartz oscillator, it is the oscillator of a kind of high accuracy and high stability, be widely used in all kinds of oscillating circuits such as colour TV, computer, remote controller, and in communication system for frequency generator, provide reference signal for data processing equipment clocking with for particular system.Please refer to accompanying drawing 1; at present; the connected mode of the connecting circuit of crystal oscillator is normally connected in series respectively a resonant capacitance between the two ends of crystal oscillator and ground; in traditional crystal oscillating circuit; the size of common two resonant capacitances is identical, and in actual applications, conventionally can cause the actual output frequency of crystal oscillator not identical with theoretical value; thereby can cause use error, affect the quality of whole system.

Summary of the invention

Different with actual frequency of utilization for the above-mentioned crystal oscillator theoretical value of the prior art of mentioning, affect the shortcoming of result of use, the utility model provides a kind of new circuit that improves crystal oscillator resonance frequency, and the capacitance of its two resonant capacitances is set to different value, addresses the above problem.

The technical scheme that the utility model solves its technical problem employing is: a kind of circuit that improves crystal oscillator resonance frequency, this circuit is different according to the different resonant capacitances of selecting of distance between crystal oscillator and use module.

The technical scheme that the utility model solves its technical problem employing further comprises:

The size of the resonant capacitance C1 connecting on described crystal oscillator the first pin is:

，

Wherein, C1 is the size of resonant capacitance C1, the frequency size that f is crystal oscillator, and L1 is that the first pin of crystal oscillator X1 arrives the distance using between module;

The size of the resonant capacitance C2 connecting on crystal oscillator the second pin is:

，

Wherein, C2 is the size of resonant capacitance C2, the frequency size that f is crystal oscillator, and L2 is that the second pin of crystal oscillator X1 arrives the distance using between module.

The beneficial effects of the utility model are: the utility model is by being designed to the capacitance of two resonant capacitances the way of different value, to solve the crystal oscillator theoretical value problem different with actual frequency of utilization, actual frequency value when it is used approaches theoretical value to the full extent.

Below in conjunction with the drawings and specific embodiments, the utility model is described further.

Accompanying drawing explanation

Fig. 1 is crystal oscillator connecting circuit figure.

Embodiment

The present embodiment is the utility model preferred implementation, and other all its principles are identical with the present embodiment or approximate with basic structure, all within the utility model protection range.

Please refer to accompanying drawing 1, crystal oscillator in the utility model is identical with connected mode of the prior art with the method for attachment of circuit, at crystal oscillator X1 two ends, cross-over connection has a resonant capacitance respectively and between ground, two resonant capacitances are respectively C1 and C2, the crystal oscillator X1 other end is connected in MCU, communication module or other modules that needs to use, in the utility model, the size of the polarization electric capacity of selecting and the pin of crystal oscillator X1 arrive the distance dependent system using between module, according to

principle, when crystal oscillator X1 to use between module distance L 1 ≠ L2 time,

The size of resonant capacitance C1 is

,

Wherein, C1 is the size of resonant capacitance C1, the frequency size that f is crystal oscillator, and L1 is that the first pin of crystal oscillator X1 arrives the distance (unit is rice) using between module;

The size of resonant capacitance C2 is ,

Wherein, C2 is the size of resonant capacitance C2, the frequency size that f is crystal oscillator, and L2 is that the second pin of crystal oscillator X1 arrives the distance using between module.

Calculate the size of the value of capacitor C 1 and capacitor C 2 according to above-mentioned formula, then, select the electric capacity of a suitable size according to nearby principle, thereby can solve the problem that crystal oscillator theoretical value is different with actual frequency of utilization.

The utility model is by the capacitance of two resonant capacitances being designed to the way of different value, and to solve the problem that crystal oscillator theoretical value is different with actual frequency of utilization, actual frequency value when it is used approaches theoretical value to the full extent.

Claims (1)

1. a circuit that improves crystal oscillator resonance frequency, is characterized in that: described circuit comprises crystal oscillator and the resonant capacitance C1 and the resonance capacitor C 2 that are connected to crystal oscillator two ends, and the size of the resonant capacitance C1 connecting on crystal oscillator the first pin is:

，

Wherein, C1 is the size of resonant capacitance C1, the frequency size that f is crystal oscillator, and L1 is that the first pin of crystal oscillator X1 arrives the distance using between module;

The size of the resonant capacitance C2 connecting on crystal oscillator the second pin is:

，

Wherein, C2 is the size of resonant capacitance C2, the frequency size that f is crystal oscillator, and L2 is that the second pin of crystal oscillator X1 arrives the distance using between module.