MRI: Acquisition of High Speed Mixed Signal Test Equipment

EIA 02-15753柯林斯，奥利弗圣母大学核磁共振成像：高速混合信号测试设备的采购这项提案研究了正交和Sigma Delta调制/解调，支持使用模拟器进行实验验证的通信/信号处理研究。将探索在Sigma Delta数模和模数转换中的新思想的实验验证。Sigma Delta调制允许本质上线性的两级量化器通过将量化噪声从信号频带移开以通过滤波去除来再现高分辨率信号。Sigma Delta调制器试图找到1‘S和-1’S的最佳序列，使得在滤波之后，该1‘S和-1’S序列与给定的相同滤波、离散时间、单位限幅序列滤波之间的欧几里德距离的平方最小。这项研究旨在表明，Sigma Delta调制是一种粗略的优化算法，实用的技术足以很好地解决这一优化问题，从而提高动态范围，超出目前的最先进水平。PI声称，实质性的改进几乎肯定会暴露即使是单位量化器固有的非理想性。由于其输出端不完美的阻抗匹配反射产生的位对位的相互作用，即使是单个位D到A也会产生噪声和杂散信号。所需的设备包括三个高速混合信号测试：数据生成器、网络分析器和信号分析器，它们将允许研究这些影响，并允许设计更好的单比特和多比特量化器。数据发生器将被用作波分复用项目中的刺激源；网络分析仪的优越量程将为微波遥感项目做出贡献。预计模拟到数字和数字到模拟的带宽和动态范围都会有所改善。每当数字计算必须连接到物理世界(例如，通过天线辐射模拟信号)时，这些设备都很重要。由于数字革命依赖于这些转换，因此接口对于发送和存储信息至关重要。在依赖这些转换的制造系统中，如个人CD播放机、蜂窝电话、高清晰度电视、计算机调制解调器、深度通信系统，提高性能和降低复杂性将使我们所有人都受益。此外，除了支持研究，这些设备还将支持三个本科课程的增强项目，并有助于使学生在雇用和指导所需设计项目方面对行业具有吸引力。

EIA 02-15753Collins, OliverUniversity of Notre DameMRI: Acquisition of High Speed Mixed Signal Test Equipment This proposal, studying quadrature and Sigma Delta modulation/demodulation, supports communications/signal processing research for experimental validation using simulators. Experimental verification of new ideas in Sigma Delta digital-to-analog and analog-to-digital conversion will be explored. Sigma Delta modulation allows an intrinsically linear two level quantizer to reproduce a high resolution signal by shifting the quantization noise away from the signal band for removal by filtering. The Sigma Delta modulator tries to find the optimal sequence of +1's and -1's such that, after filtering, the squared Euclidean distance between this sequence of +1's and -1's and a given, identically filtered, discrete-time, unity-amplitude-limited sequence filtering is minimized. The research aims to show that Sigma Delta modulation constitutes a crude optimization algorithm and that practicable techniques solve this optimization problem well enough to improve dynamic range beyond the current state-of-the-art. The PI claims that the substantial improvement will almost certainly expose the inherent nonidealities of even single bit quantizers. Because of the bit-to-bit interactions produced by reflections from imperfect impedance matches at its output, even single bit D to A generates noise and spurious signals. The equipment requested, three pieces of high speed, mixed signal test: a data generator, a network analyzer, and a signal analyzer, will allow investigation of these effects and permit the design of better single- and multiple-bit quantizers. The data generator will be used as a stimulus source in a wavelength division multiplexing project; the superior range of the network analyzer will contribute to a microwave remote sensing project. Improvement in analog-to-digital and digital-to-analog bandwidth and dynamic range is expected. The devices are important whenever digital computation must be interfaced to physical world (e.g., getting the analog signal radiated by an antenna). Since the digital revolution depends on these conversions, the interface is critical to send and store information. Improved performance and reduced complexity in manufacturing systems that depend on these conversions, such as personal CD players, cellular telephones, high definition TV, computer modems, deep communication systems would benefit us all. Moreover, in addition to supporting research, the equipment will support enhanced projects in three undergraduate courses and contribute to make the students attractive to industry for both hiring and mentoring the required design projects.