A Surface Acoustic Wave Oscillator Based on Multiple Couplers

Abstract

The invention discloses a surface acoustic wave oscillator based on a multi-strip coupler. The surface acoustic wave oscillator comprises a direct current power source and a direct current interference filtering circuit, and the output end of the direct current power source is connected with the direct current interference filtering circuit. The surface acoustic wave oscillator further comprises a common collector amplifying circuit and a capacitive feedback type circuit, the direct current interference filtering circuit is connected with a parallel circuit in series, the parallel circuit is formed by the common collector amplifying circuit and the capacitive feedback type circuit, the capacitive feedback type circuit is composed of a surface acoustic wave device and a matched circuit in series, and the output end of the common collector amplifying circuit is connected with the output end of the matched circuit. Due to the fact that the surface acoustic wave device in the oscillator is designed based on the multi-strip coupler, therefore, the bulk acoustic wave and sidelobe suppression capacity of the surface acoustic wave oscillator is improved compared with that of a common oscillator, and the output oscillation signals have the better periodicity and stability.

Description

technical field [0001] The invention relates to an oscillator, in particular to a surface acoustic wave oscillator based on multiple couplers. Background technique [0002] An oscillator is an electronic system that can convert the power supplied by a DC power supply into a signal output with a certain frequency and amplitude without an external excitation signal. Due to its high frequency stability and small access coefficient, surface acoustic wave oscillators are widely used in various signal sources such as sine waves and square waves, as well as high-frequency and very high-frequency fields such as carrier circuits and sensors. [0003] As the core component of the surface acoustic wave oscillator, the surface acoustic wave device's design parameters not only determine the frequency of the oscillation signal of the surface acoustic wave oscillator, but also its performance, especially the bulk acoustic wave suppression and sidelobe suppression in the frequency character...

AI Technical Summary

Problems solved by technology

At this time, for the traditionally used equal-interdigitated and dual-transducer SAW devices, the bulk acoustic wave signal will be coupled to the output transducer, which will affect the response characteristics of the SAW device, causing the SAW The spectral characteristic curve of the wave device has too much ripple in the band and the false response of the right band is higher than the synchronous frequency of the surface acoustic wave

At the same time, using the traditionally used equal-interdigitated, double-transducer SAW device, the first side lobe of the device's spectral characteristic curve is only 13.26dB lower than the peak value of the main lobe. If signal reflection, bulk acoustic wave Interference, false response and other problems, the difference between the side lobe and the main lobe peak will be much smaller than this value, therefore, it is difficult to separate the side lobe signal from the main lobe signal in the measurement, which will cause a lot of interference

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