Design And Research Of 16-bit 12GSPS D/A Converter Digital Up-conversion

The function of digital up-conversion is to shift the spectrum of the baseband signal.The design of digital upconverter in this paper mainly includes two parts: interpolation filtering and quadrature modulation.In order to make the data rate meet the needs of the carrier signal,we perform interpolation filtering on the input low-frequency signal to achieve the purpose of up-sampling.A digitally controlled oscillator based on CORDIC algorithm is designed to generate quadrature modulated carrier signal.The CORDIC algorithm can achieve a higher-precision sine function without increasing resource requirements on a large scale.Complete the spectrum shift and modulate the signal to a higher frequency.This article mainly researches and designs the digital upconverter of the 16-bit 12 GSPS D/A converter,and realizes the matching between the interface data receiving rate and the conversion rate of the high-speed DAC core for the 16-bit 12 GSPS D/A converter to ensure the 12 GSPS D/A converter performance and reliability.After studying the theories of sampling theorem,sampling rate multi-level conversion,interpolation filtering,quadrature modulation and other theories,the overall design scheme of the digital up-conversion system is determined,and the design tasks of each module are decomposed.In order to realize programmable interpolation filtering and compensate with the DAC,a half-band filter and a FIR filter are selected.The realization algorithm of the digitally controlled oscillator is improved,the realization speed and accuracy are improved,and the influence of spurs is reduced.In terms of implementation,the design of the digital up-conversion module is combined with the design of the D/A converter,and multiple modules are designed for each module of the circuit to reduce the working frequency of the digital module.At the same time,an optimized design has been added to the circuit module to reduce hardware overhead.