Calibration system for SLC 476 MHz to 2856 MHz multipliers

The two mile long Main Drive Line (MDL) distributes 476 MHz at each of the 31 sectors along its length. Each of the 31 sectors has a six times multiplier which drives the 2856 MHz phase reference system for that sector. This system is used to set and maintain phase of the accelerator structures over time. During previous runs significant down time resulted from sector phasing which was required after multiplier replacement. A system was designed to calibrate the phase of the 476 MHz input to the phase of the 2856 MHz output of the multiplier units. This enabled multipliers to be replaced without rephasing sectors.