Device and method for measuring doppler frequency shift based on dual parallel Mach-Zehnder modulator

Abstract

The invention discloses a device and a method for measuring the doppler frequency shift based on a dual parallel Mach-Zehnder modulator, and relates to the technical field of the microwave technology and the optical communication technology. The device is shown in the figure and includes a laser diode (LD), a dual parallel Mach-Zehnder modulator (DPMZM), an erbium doped fiber amplifier (EDFA), a dense wavelength division multiplexing (DWDM) and a photodetector (LD). According to the technical scheme of the invention, echo signals and sending signals are subjected to carrier-suppressed double sideband modulation by the dual parallel Mach-Zehnder modulator (DPMZM). Meanwhile, the powers of upper and lower sidebands, and the phase difference between upper and lower sidebands are fully utilized for the measurement of the magnitude and the positive / negative attribute of the doppler frequency shift. Therefore, the measurement error is small. The range of the carrier frequency can be freely regulated within a large range, while the deterioration of the measurement error is avoided. In addition, the device has fewer parts, and is simple in structure and easy in operation. The device and the method have a good application prospect in the fields of radar, reconnaissance systems and the like.

Description

technical field [0001] The invention relates to the technical field of optical communication and microwave technology, and mainly relates to the realization of Doppler frequency shift measurement of microwave signals based on dual parallel Mach-Zehnder modulators. Background technique [0002] The Doppler frequency shift (DFS) phenomenon caused by the Doppler effect is widely used in mobile communication, microwave / millimeter wave measurement, electronic warfare and radar systems. Therefore, it is of great significance to accurately measure the Doppler frequency shift. Traditional electronic measurement methods are generally based on coherent oscillators and narrow-band mixers. Fourier analysis, time-frequency analysis, quadrature mixing and other methods are used to measure DFS, and the measurement devices work in a narrow specific frequency band. As the frequency of radio signals continues to increase, people have higher and higher requirements for the multifunctional int...

AI Technical Summary

Problems solved by technology

In order to measure the positive and negative of DFS, a frequency reference module is generally added, but at the same time, the complexity of the system and the source of error factors are increased; the method of combining quadrature frequency mixing and balanced detection can also be used to compare the quadrature two signals Phase difference to determine positive and negative

The second way of thinking is accurate in measurement, but the current reported method uses more modulators and discrete devices, the system is too complex, and there are many sources of error, which needs further improvement

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