Tuning of Kilopixel Transition Edge Sensor Bolometer Arrays with a
  Digital Frequency Multiplexed Readout System
  A digital frequency multiplexing (DfMUX) system has been developed and used
to tune large arrays of transition edge sensor (TES) bolometers read out with
SQUID arrays for mm-wavelength cosmology telescopes. The DfMUX system
multiplexes the input bias voltages and output currents for several bolometers
on a single set of cryogenic wires. Multiplexing reduces the heat load on the
camera's sub-Kelvin cryogenic detector stage. In this paper we describe the
algorithms and software used to set up and optimize the operation of the
bolometric camera. The algorithms are implemented on soft processors embedded
within FPGA devices operating on each backend readout board. The result is a
fully parallelized implementation for which the setup time is independent of
the array size.
