Broadband Chirp Microwave Signal Generator

Abstract

The invention provides a wideband linear frequency modulated microwave signal generator. A voltage controlled oscillator generates linear frequency modulated signals; the linear frequency modulated signals are divided into three paths through a power divider, wherein the A path of signals are outputted directly, the B path of signals are directly inputted into the first input port of a frequency mixer, and the C path of signals are subjected to time delay of a delay line and then are inputted into the second input port of the frequency mixer; the output signals of the frequency mixer are subjected to analog-to-digital conversion, so that digital signals can be generated; the digital signals are inputted into an FPGA signal processing module for analysis and processing, so that fine modulating signals in a digital form are generated; the fine modulating signals are subjected to digital-to-analog conversion, so that fine modulating signals in an analog form can be generated; and the fine modulating signals in the analog form are inputted into the voltage controlled oscillator so as to control the frequency of the output signals of the voltage controlled oscillator. According to the wideband linear frequency modulated microwave signal generator of the invention, the advantage of large bandwidth of an original analog technology is reserved, and by means of the powerful data processing ability of an FPGA, a feedback loop is built, and therefore, the defects of frequency instability and poor linearity of a traditional analog method can be eliminated.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a broadband linear frequency modulation microwave signal generator. Background technique [0002] The speed measurement accuracy and speed resolution of radar mainly depend on the time domain structure of the signal. In order to improve the speed measurement accuracy and speed resolution, the signal is required to have a large time width. Ranging accuracy and distance resolution mainly depend on the frequency domain structure of the signal. In order to improve ranging accuracy and distance resolution, the signal is required to have a large bandwidth. The range resolution can be improved by using a large broadband signal, which makes fine imaging of radar targets possible. In addition, the large broadband signal can provide more information about the frequency domain of the target, and provide a better basis for target identification. In recent years, with the in-de...

AI Technical Summary

Problems solved by technology

Among them, the analog method uses a sawtooth voltage to control a voltage-controlled oscillator (VCO) to generate a linear frequency modulation signal. The disadvantages of this method are: lack of flexibility; poor anti-interference of analog circuits leads to frequency instability and drift with temperature; linearity bad

The disadvantage of this method is that the bandwidth is small, and the subsequent spread spectrum method will damage the linearity and frequency resolution of the output signal to a certain extent, which greatly limits the ranging accuracy and distance resolution of the radar.

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