A variable rate modulator and signal generation method based on off-chip storage

Abstract

The embodiment of the invention provides a variable rate modulator based on off-chip storage, and a signal generation method. The signal modulator comprises a multichannel parallel DDS module based onan off-chip memory module, wherein the off-chip memory module is used for storing a baseband waveform of a processed signal; and the multichannel parallel DDS module is used for reading the basebandwaveform from the off-chip memory module according to the multichannel parallel DDS technology, modulating the baseband waveform to obtain a modulated signal of an arbitrary rate, and outputting the modulated signal. According to the variable rate modulator based on off-chip storage, and the signal generation method provided by the embodiment of the invention, under the condition of keeping an information sequence unchanged and keeping the precision of a hardware platform and a digital-to-analog converter unchanged, the baseband waveform generated by a larger interpolation coefficient N and aquantization bit number W is stored through the off-chip memory, so that the quality of a digital communication signal is significantly improved, the spurious noise is greatly inhibited, the phase noise is reduced, the EVM is improved, and the performance of the digital signal is improved.

Description

technical field [0001] The invention relates to the communication field, in particular to a variable rate modulator based on off-chip storage and a signal generating method. Background technique [0002] With the continuous development of communication technology, in order to meet the higher requirements for channel capacity and communication quality, more and more digital modulation methods are used in various communication systems to realize long-distance transmission of information. Digital modulation technology has many advantages such as strong anti-interference and disorder ability, easy to control errors, and easy to keep secret, so it is widely used in many fields. [0003] The system's requirements for the quality of digital communication signals are getting higher and higher with the development of technology. The parameters commonly used to measure the quality of digital communication signals include: Error Vector Magnitude (EVM), spurs, and phase noise. [0004]...

AI Technical Summary

Problems solved by technology

[0005] Digital communication signals can be generated by Direct Digital Synthesizer (hereinafter referred to as DDS). Due to the wide application of digital communication signals, the quality requirements for this technology are more stringent. The existing digital communication signals are in the error vector Unsatisfactory performance on amplitude, spurious and phase noise, so a high-performance signal modulator and signal generation method is urgently needed to solve this problem

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