Chirp Generator with Predistortion

Abstract

The invention provides a linear frequency-modulated signal generator with a predistortion function. The linear frequency-modulated signal generator comprises an FPGA unit, a digital-analog conversion unit and a filtering unit, wherein the FPGA unit is used for generating a phase position predistortion digital linear frequency-modulated signal and conducting amplitude predistortion processing on the phase position predistortion digital linear frequency-modulated signal to generate two orthogonal amplitude-phase predistortion digital linear frequency-modulated signals; the digital-analog conversion unit is connected with the output end of the FPGA unit and used for converting the two orthogonal digital linear frequency-modulated signals subjected to amplitude-phase predistortion into two orthogonal discrete analog linear frequency-modulated signals; the filtering unit is connected with the digital-analog conversion unit and used for filtering out frequency components beyond a preset frequency range of the two orthogonal discrete analog linear frequency-modulated signals to obtain two continuous orthogonal analog linear frequency-modulated signals. The linear frequency-modulated signal generator can compensate for non-linear influences of an analog circuit on the linear frequency-modulated signals by means of amplitude-phase predistortion processing, and guarantee that the high-quality linear frequency-modulated signals can be obtained finally.

Description

technical field [0001] The invention relates to the technical field of electronic components in the electronics industry, in particular to a chirp signal generator with a pre-distortion function. Background technique [0002] The linear frequency modulation signal refers to the linear relationship between the frequency and time of the signal. It uses phase modulation and pulse compression technology to reduce the peak power of the transmitter and increase the radar range. This advantage makes it widely used in the field of synthetic aperture radar, and how to generate chirp signals has become a hot spot in theoretical and engineering research. [0003] There are two traditional methods for generating chirp signals: digital waveform direct synthesizer and digital waveform storage direct reading method. Their advantages and disadvantages are as follows: [0004] 1) Digital Waveform Direct Synthesizer (Direct Digital Synthesis-DDS) can generate high-quality single-pulse chirp ...

AI Technical Summary

Problems solved by technology

The problems caused by the expansion of large-capacity and high-speed DRAMs are: (1) poor signal quality; (2) in order to meet the conversion speed requirements of high-speed DACs, a large number of DRAMs is required; (3) there are many connections with the FPGA, which takes up a lot of IO resources; (4) The control of DRAM is complex, especially the need to implement dual ports; (5) The structure is complex, the area and power consumption are relatively large, and the resulting cost is also high

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