Enhanced functionality and performance of the longitudinal damping system at the ALS using a new VXI based processing system

The ALS longitudinal feedback electronics, designed and developed at the Stanford Linear Accelerator center (SLAC), has been operating very reliably at the ALS for over four years. Recently a new VXI based implementation of the entire RF and timing electronics has been built, tested, and will soon replace an earlier prototype installation. The components designed are contained in three VXI packages along with a VXI controlled system oscillator chassis. The new system contains a number of functional enhancements that most notably include: enhanced timing control, internal temperature monitoring of all VXI modules, simulated beam signal generation, automatic locking of the phase detector servo loop, and the monitoring and alarm of critical RF signal levels. The details of the design and implementation of the VXI modules along with performance characteristics are presented below