Author: Yang, J.
Paper Title Page
TUPOA40 Low Noise Digitizer Design for LCLS-II LLRF 364
 
  • G. Huang, L.R. Doolittle, Y.L. Xu, J. Yang
    LBNL, Berkeley, California, USA
  • Y.L. Xu, J. Yang
    TUB, Beijing, People's Republic of China
 
  Modern accelerators use a digital low level RF controller to stabilize the fields in accelerator cavities. The noise in the receiver chain and analog to digital conversion (ADC) for the cavity probe signal is critically important. Within the closed-loop bandwidth, it will eventually become part of the field noise seen by the beam in the accelerator. Above the open-loop cavity bandwidth, feedback processes transfer that noise to the high power drive amplifiers. The LCLS-II project is expected to use an undulator to provide soft X-rays based on a stable electron beam accelerated by a superconducting linac. Project success depends on a low noise, low crosstalk analog to digital conversion. We developed a digitizer board with 8 ADC channels and 2 DAC channels. The broadband phase noise of this board is measured at <-151\thinspace dBc/Hz, and the adjacent channel crosstalk is measured at <-80\thinspace dB. In this paper we describe the digitizer board design, performance test procedures, and bench-test results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA40  
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