Design And Verification Of A16Bits Sigma Delta Dac Interpolation Filters

MEMS micro-machined gyroscope has been widely used in the field ofaerospace, automotive, military equipment and electronic products for itsadvantages of integration, miniaturization, intelligent, low power consumption, highreliability, etc. Technologically advanced human societies require specialized toolsand equipment to enable their diverse and mobile activities, which means theincreasingly high requirements for the performance, size and portable degrees ofgyro. Therefore, further digitization of silicon micro-machined gyroscope becomesextremely important，which can significantly improve its performance. In silicongyroscope interface circuit, the precision of the digital to analog converter level hasa significant influence on system performance. This topic mainly aimed at theresearch of silicon gyroscope DAC interface circuit, three important module ofinterpolation filter, the sigma delta modulator, low DAC analog reconstruction filterwere deep analyzed and implemented.In the design of interpolation filter, working principle is firstly analyzed, thenhardware cost and performance are considered carefully. Three-stage cascadestructure is chosen to reduce the frequency by128times and filter noise out of band,which is made up of CIC filter, compensation filter and halfband filter. After theconduct of interpolation filter. Firstly, three filters are designed in MATLABrespectively; and then RTL-level design of filters are made suing Verilog HDL,consisting of filter codes, testbench and clock, simulation of them is also made. Atlast, DC synthesize of decimator is made using Synopsys DC with standard unitlibrary developed by MEMS center and layout of decimator filter is made usingEncounter.Using Matlab simulates digital filter circuit system, and using modelsimsimulates the circuit system. Then using verilog code validates the function of thecircuit. The digital filter circuit satisfies16bit solution Sigma Delta converter.