MRI: Acquisition of High Speed Mixed Signal Test Equipment

该提案研究正交和σ δ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Sigma Delta数模转换和模数转换的新想法的实验验证。σ δ调制允许本质线性二电平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。σ δ调制器试图找到+1和-1的最优序列，这样，在滤波后，+1和-1序列与给定的、相同滤波的、离散时间的、单位幅度限制的序列滤波之间的平方欧氏距离最小。该研究旨在表明，Sigma Delta调制构成了一种粗糙的优化算法，可行的技术可以很好地解决这一优化问题，从而提高动态范围，超过目前的水平。PI声称，实质性的改进几乎肯定会暴露出即使是单比特量化器的固有非理想性。由于输出端不完美阻抗匹配反射产生的位对位相互作用，即使是单位D到A也会产生噪声和杂散信号。所要求的设备，三件高速混合信号测试：数据发生器，网络分析仪和信号分析仪，将允许调查这些影响，并允许设计更好的单比特和多比特量化器。所述数据发生器将用作波分复用项目中的刺激源；网络分析仪优越的测量范围将有助于微波遥感工程。期望模数转换和数模转换带宽和动态范围的改进。每当数字计算必须与物理世界相连接时（例如，通过天线获得模拟信号），这些设备就很重要。由于数字革命依赖于这些转换，接口对于发送和存储信息至关重要。依赖于这些转换的制造系统，如个人CD播放机、蜂窝电话、高清电视、计算机调制解调器、深度通信系统，其性能的提高和复杂性的降低将使我们所有人受益。此外，除了支持研究之外，这些设备还将支持三个本科课程的增强项目，并有助于使学生在招聘和指导所需的设计项目方面对工业界具有吸引力。

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.