Carrier Phase Optimization for Frequency Division Multiplexing of Low Temperature Detectors

A large number of low temperature detectors may be read out via few wires using frequency division multiplexing. In this scheme, each detector is biased by a sine wave with a unique carrier frequency. Numerous carriers can be combined in a single pair of wires. However, the combined signals occasionally result in large peak amplitudes in the bias or the readout. This stresses the capabilities of the electronics. We developed an efficient algorithm to optimize the phases and frequencies of the carriers in order to obtain a low crest factor. We also find that more regularly spaced carrier frequencies result in a lower crest factor, compared to irregularly spaced carriers.