Suitable techniques for reading out large arrays of metallic magnetic calorimeters are very challenging and demand optimal performance in each system stage to preserve intrinsic fast signal rise time, excellent energy resolution, large energy dynamic range, and highly linear detector response. A multiplexer based on superconducting quantum interference device is the key component in achieving this goal. Linearity of the response requires a technique called flux-ramp modulation, which generates a phase-modulated complex waveform according to the sensor signal. At the end-cap of the signal processing chain it is currently recovered by a demodulation process referred to as Fourier measurement. In this letter, we prove that the mentioned method is equivalent to a maximum likelihood estimation, build an analogy to the sensor array-based direction of arrival estimation, propose an alternative approach based on the eigenvalue decomposition of a correlation matrix, present the mathematical formulation, discuss the results, and compare both methods. Our method is robust against transients due to flux ramp returning point and allows proper estimation in large phase ranges.

中文翻译：

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在微波 SQUID 多路复用器上读取能量脉冲：一种基于传感器阵列的方法

读取大型金属磁性热量计阵列的合适技术非常具有挑战性，需要在每个系统阶段都具有最佳性能，以保持固有的快速信号上升时间、出色的能量分辨率、大能量动态范围和高度线性的探测器响应。基于超导量子干涉器件的多路复用器是实现这一目标的关键部件。响应的线性需要一种称为通量斜坡调制的技术，该技术根据传感器信号生成相位调制的复合波形。在信号处理链的末端，它当前通过称为傅立叶测量的解调过程恢复。在这封信中，我们证明了上述方法等价于最大似然估计，建立与基于传感器阵列的到达方向估计的类比，提出一种基于相关矩阵特征值分解的替代方法，提出数学公式，讨论结果，并比较两种方法。由于通量斜坡返回点，我们的方法对瞬变具有鲁棒性，并允许在大相位范围内进行正确估计。