SQUID multiplexers for transition-edge sensors

We review the superconducting quantum interface device (SQUID) multiplexer schemes that are being developed to instrument large-format arrays of superconducting transition-edge sensors. We discuss the choice of an orthogonal basis set to represent the multiplexed signal (such as time or frequency) and the practical issues of implementation, including bandwidth-limiting filters, SQUID noise, and power dissipation.