Design Of A Low Power Consumption And High Accuracy Delta-sigma Modulator

The idea of software radio emerged, which has a huge impact on the wireless communication Transceiver system in the development of full digitalization、 miniaturization and modularization, but also ensures the validity and accuracy of the transmission. And digital signal processing techniques has been extended to the microwave region. This permits the wireless transceiver system can deal with the radio-frequency signal. Analog-to-digital conversion is the key module of the receiver system, and it is becoming more and more important. The traditional analog-to-digital converter in integration and accuracy of the conversion has many flaws, hence there is an urgent need for A/D converter of high integration and high precision. Oversampling delta sigma (△-∑; delta sigma) A/D converter has the advantage of high precision, good linearity, anti-interference ability and easily digital integration, which is rapidly becoming the development trend and the mainstream technology of the high precision A/D converter. As the core of the delta-sigma analog-to-digital converter, the delta-sigma modulator directly determine the merits of the latter.This paper focus on the research and improvement of the delta-sigma modulator structure on the performance. To simplify its structure, improve performance as the goal, combined with advantages of delta-sigma modulation technology, according to three parameters (sampling rate、structure order and the number of quantization bits) on the modulator performance directly influence to determine the value, The ideal low-pass CIFB structure is selected from the four structure models, this structure adopts the technology of low distortion and noise coupling technology. To ensure the structure of the signal transmission function is equal to 1 and at the same time make the noise transfer function all zero point is located at dc, namely the z= 1; and noise coupling technology can effectively reduce power consumption. In order to better improve △-∑ modulator performance, reduce the noise power of the signal frequency band, in the introduction of zero CIFB structure optimization technology, through the negative feedback loop filter coefficient created a resonator, coefficient of structure optimization, I successfully design a three-order-15 bites single loop △-∑ modulator of low power loss and high precision. When the input signal is 10 kHz, and the rate of over sampling is 64, Simulation results indicate that the signal to noise ratio is 91.6 dB, the conversion accuracy is over 15.