The Research On Sigma-delta Modulator And Its Applications In Mixed-signal System

With digital system scales increase and integrated technology development, the powerful system-on-chip (SOC) has come into our life. When they are created to have high performaces, the SOCs are required the abiltity to process the analog signal directly, that is, the mixed-signal SOC ( MSSOC).Realizing the analog integrated circuits with the CMOS digital technology is the hot spot and difficulty in the investigation of the modern large scale SOC. The paper studied deeply the operational principle of Sigma-Delta modulator and its design method, the processing algorithm of bit stream signal, and the structure and test of mixed SOC. The paper proposes a novel mixed SOC based on Sigma-Delta modulator, a new bit-stream signal processing structure and algorithm, and the structure and algorithm to test high precision A/D convertors.The significant investigation results of the paper are as follow:(1) The behavior simulation model of switched-capacitor Sigma-Delta modulator circuits is investigated deeply and created in simulink. The Sigma-Delta modulator simulation has high precision and fast performance for the nonideal factors being added into the model.(2) We study the realizing structure and method of three high performance Sigma-Delta modulators and propose the corresponding measures and method to compensate their realizing lack in circuits. We investigate deeply the variable structure theory to analyze the high-order Sigma-Delta modulator and the stability condition and propose the condition on the discrete varibal structure system being the Sigma-Delta modulator and the theory to test stability.(3) We designed a 16-bit Sigma-Delta A/D convertor in 0.18um technology and implemented the circuit design, the circuit structure selecting and the layout design, and the chip test.(4) We study deeply the bit-stream processing directly algorithm, its structure and circuits realizaiotn. A novel bit stream adder is proposed in the paper and used to compose other modules such as the multiplier, and its application.(5) We introduce the ADC performance parameters and the usual test method. The method of combining FFT spectrum analysis and ADC model is proposed to test the high precision ADC with the low precision stimulus. A novel built-in-self-test SOC circuit is proposed in chapter VI and a high built-in precision stimulus is generated using the Sigma-Delta technology.We have obtained the anticipated goal in the paper and implemented the Sigma-Delta Modulator mixed signal SOC in the standard digital CMOS technology. The studied results achieved in the paper are of significance in theory and design method to apply the high precision mixed signal SOC.