LTE230数字中频发送机的设计

摘要

Aiming at the problem of high speed data transmission unreachable directly due to discrete distribution and narrow bandwidth of frequency point on 230 MHz frequency band,a new type of low cost,high reliability and high performance all digital IF(Intermediate Frequency)transmitter is designed based on the analysis the spectrum feature of 230 MHz frequency band and LTE230 frame structure. The transmitter uses time division multiplexing design method and two-stage digital filtering, interpolating and mixing structure,and it can aggregate 40 discrete frequency points on 230MHz frequency band to obtain broad band transmission effect with small circuit area.After passing simulation and FPGA verification,the transmitter has been integrated into LTE230 wireless communication baseband chip and runs stably for a long time in pilot project,it fully indicates the design of digital IF transmitter is very successful.%针对230 MHz频段频点分布离散、带宽窄、无法直接进行高速数据传输的问题,在分析230 MHz频段频谱特点及LTE230帧结构的基础上,设计出一种新型的低成本、高可靠性、高性能的全数字中频发送机,该发送机采用时分复用的设计方法和两级数字滤波、插值、混频的结构,以较小的电路面积实现了对230 MHz频段40个离散频点的聚合,从而达到宽带传输的效果.经仿真及FPGA验证通过后,该发送机已集成到LTE230无线通信基带芯片并在试点项目中长时间稳定运行,充分表明数字中频发送机的设计是很成功的.