  The Birmingham Solar Oscillations Network (BiSON) observes acoustic
oscillations of the Sun. The dominant noise source is caused by fluctuations of
Earth's atmosphere, and BiSON seeks to mitigate this effect by combining
multiple rapid observations in alternating polarisation states. Current
instrumentation uses bespoke Pockels-effect cells to select the polarisation
state. Here, we investigate an alternative off-the-shelf solution, a liquid
crystal retarder, and discuss the potential impact of differences in
performance. We show through electrical simulation of the photodiode-based
detectors, and assessment of both types of polarisation device, that although
the switching rate is slower the off-the-shelf LCD retarder is a viable
replacement for a bespoke Pockels-effect cell. The simplifications arising from
the use of off-the-shelf components allows easier and quicker instrumentation
deployment.
