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Method for improving frequency stability of sound surface wave oscillator

A technology of oscillator frequency and surface acoustic wave, applied in the direction of output stability, electrical components, etc., can solve the problems of insufficient oscillator frequency stability, non-coincidence, large loss at the center frequency, etc., and achieve obvious short-term frequency stability, Improvement of frequency stability, effect of short-term frequency stability improvement

Inactive Publication Date: 2010-10-06
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to design or process reasons, the center frequency point of the detector and the lowest loss point often do not coincide. When they do not coincide, the loss at the center frequency is relatively large. At this time, phase matching is performed at the center frequency, resulting in a stable frequency of the oscillator. not high enough

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  • Method for improving frequency stability of sound surface wave oscillator
  • Method for improving frequency stability of sound surface wave oscillator
  • Method for improving frequency stability of sound surface wave oscillator

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Embodiment 1

[0030] In this embodiment, the surface acoustic wave oscillator adopts the structure of double-loop difference frequency output (such as figure 1 As shown), the phase matching is completed by using coaxial cable phase shifting, and the first SAW detector 3 and the second SAW detector 3' use SAW double-terminal pair resonator structures. Measure the frequency response curve of the first surface acoustic wave detector 3 with network analyzer as Figure 2A and Figure 2B shown, where Figure 2A is the amplitude-frequency response curve, Figure 2B The specific test parameters of the first surface acoustic wave detector 3 of the phase-frequency response curve are as follows: the center frequency is 332.6MHz, the phase at the center frequency is 80°, the loss at the center frequency is 4.6dB, the frequency at the lowest loss is 332.63MHz, the lowest The phase at the loss is 102°, and the loss at the lowest loss is 3.7dB. The second surface acoustic wave detector 3' in the secon...

Embodiment 2

[0038] In this embodiment, the SAW oscillator adopts the structure of the difference frequency output of the double oscillation loop, the phase shifter is selected for phase matching, and the first SAW detector 3 and the second SAW detector 3' use acoustic surface wave delay line structure, the frequency response curve obtained by testing the first surface acoustic wave detector 3 with a network analyzer is as follows Figure 3A and Figure 3B shown, where Figure 3A is the amplitude-frequency response curve, Figure 3B is the phase-frequency response curve. The specific test parameters of the surface acoustic wave detector 3 are as follows: the center frequency is 302.788MHz, the phase at the center frequency is 105°, and the loss at the center frequency is 9.4dB; the minimum loss point is 302.775MHz, the phase at the minimum loss point is 116°, and the loss at the minimum loss point is 8.68dB . The second surface acoustic wave detector 3' in the second surface acoustic w...

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Abstract

The invention relates to a method for improving frequency stability of a sound surface wave oscillator. The method comprises the following steps of: 1) testing a frequency response curve of a sound surface wave detector, finding a frequency point with lowest loss in a pass band, and measuring the phase phi D of the frequency point; 2) taking a phase condition formula phi D + phi E = 2npi (n is integer) that an oscillating loop can produce oscillation, substituting the phi D obtained in the step 1 into the formula, and calculating the phase shift phi E of a circuit part of the oscillating loop; and 3) adjusting a phase shift network of the circuit part of the oscillating loop to make the phase shift of the circuit part of the oscillating loop meet the phi E obtained in the step 2) so as to finish phase matching. The phase matching can be finished by using a phase shifter or a cable. The method provided by the invention can obviously improve the frequency stability of the sound surface wave oscillator, and can reach + / - 5Hz / sec.

Description

technical field [0001] The invention relates to a method for improving the frequency stability of a surface acoustic wave oscillator, in particular to a method for improving the frequency stability of a surface acoustic wave oscillator through phase matching. Background technique [0002] The frequency stability of the SAW oscillator is one of the key factors affecting the detection limit and sensitivity of the SAW sensor, and the short-term frequency stability of the SAW oscillator is especially important for the SAW sensor with fast detection speed. The invention relates to a method for improving the frequency stability of a surface acoustic wave oscillator. [0003] In order to eliminate the influence of the external environment such as temperature and vibration on the frequency stability of the oscillator to the greatest extent, the surface acoustic wave oscillator mostly adopts the structure of the difference frequency output of the double oscillation loop (see sensors ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03L1/00
Inventor 何世堂刘久玲李顺洲刘明华王文
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI