Key Technologies Research And Verification Of Waveform Optimization For All Digital Transmitter

After digital pulse mapping and digital carrier modulation,the transmitted signal is quantized into a band limited digital radio frequency signal,and then amplified by a digital amplifier(DPA)and finally transmitted through an antenna.This transmitter architecture is called all digital transmitter architecture.The all digital transmitter has the advantages of digital communication and avoids the limitation of D/A devices' performance,at the same time,the transmitter has the advantages of high integration,miniaturization and low power consumption,so it is very valuable.In this paper,the present all digital transmitter is analyzed briefly,and the design architecture of the existing all digital transmitter is studied and improved.A new design scheme of all digital transmitter algorithm is put forward,and the quantization modulator and the optimization of the engineering parameters are studied in this scheme,which is carried out.Simulation and implementation verification and test in hardware environment are carried out,and the following research results are obtained:Firstly,in this paper,the structure of the traditional two order Sigma-Delta modulator is improved.The noise shaping of the traditional two order modulator is low-pass and the noise low point is fixed.For the variable frequency signal,the noise shaping is not good.The improved modulator noise shaping is band-pass and can be based on the variable signal.Frequency adjusts the noise low point and optimizes the performance of quantizer.Secondly,In this paper,the engineering parameters such as Lane rate,pre accentuation and aggravation and output swing of GTY in FPGA are studied,and the influence of these engineering parameters on the performance of output waveform is discussed,and a large number of tests have been made to get the conclusions of the influence of various engineering parameters on the output waveform,and the reasons for this conclusion are analyzed.The conditions of optimal engineering parameters under the hardware condition are determined.Thirdly,This paper designs the baseband hardware platform of all digital transmitters,debugs the hardware platform and tests the hardware index of the platform,and completes the verification of the full digital transmitter algorithm scheme on the hardware platform,and carries out the all digital transmitter performance test under the hardware environment of the optimal engineering parameters.The performance test mainly includes the waveform performance of the all digital transmitter in the wide carrier frequency range,and the waveform performance under the dual channel operation mode.According to the research results,the feasibility of the algorithm design scheme of the transmitter is verified.It provides a reliable hardware platform and optimal engineering parameter conditions for the FPGA realization of the later full digital transmitter.The performance index of the test is provided for the index test of the later FPGA implementation of the algorithm.