I am working with a pattern recognition problem, using 1-dimensional movement data, and some small movement patterns i'm looking at are characterized by looking like small sinuses (nice rounded curves), they appear sometimes here and there, with different duration (sometimes 1/2 period, sometimes 2 periods etc), and the amplitude and frequency is changing dynamically.

Can someone tip me of a "filter"/"pattern recognizer"/set of mathematic properties that will recognize this pattern from other types of signals? I have done some testing using neural networks (backprop) to discriminate the sinus-like patterns from everything else, but making the training set robust enough is a teedious job... Any input appreciated :)