The parameter space of an electronic three oscillator system is invest
igated and various codimension one and two bifurcations predicted by B
aesens, Guckenheimer, Kim and MacKay are identified. Sampled time-seri
es from the experimental systems are recorded and analysed for partial
mode-locking or resonance (one or two independent rational relations
between the average rates of change of the angles describing the syste
m) using knowledge of where the invariant torus lies and the torus unf
olding scheme of Ashwin and Swift. Examples of toroidal and annular ch
aos are investigated by finding bounds on the size and shape of the ro
tation set.