A 16-bit ¦²-¡÷ Ad Converter Of The Digital Part Of The Design And Realization

In present design of complete systems on a single chip, there is an increasing demand for systematic, top down design. This enables the designer to choose the right parameters for the different building blocks of the system, starting from the system specifications. In this way, the systematic design will increase the chance of a first-time-right design and therefore a faster time-to-market.This paper presents a complete analog front end for low frequency measurement applications. The part can accept low level input signals directly from a transducer and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 16 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and output update rate. Corresponding to them, we have finished the following works:The first chapter gives a brief description of related knowledge for modulator and presents the methodologies and procedures based on the comprehensive planning for the project. In chapter 2, the basic specification and general measurement are discussed. In Chapter 3, the mechanism of oversampling converters with Sigma-delta modulator is discussed. In chapter 4, systematic design is carried out and presents the specific parameter indexes according to the characteristics, basic functions and the related requirements of the chip. Chapter 5 goes on with the design and realization of the digital circuits, selects related parameters for the SRAM, ROM, TIMER, digital filer, serial data interface, and the control logic part. System structure is designed and system test is made. Chapter 6 makes a conclusion for this project.