Editing Chart recorder (section)

== Light beam oscillograph ==
Another type of paper chart recorder was the ''light beam oscillograph''. It had a bandwidth of ~5 kHz full scale (approximately 100 times higher than the typical pen recorders of the day). The original models used a small mirror attached to a [[galvanometer]] to aim a high-intensity beam of light at photosensitive paper. The combination of the mirror's tiny mass combined with a chart drive that could move the paper up to {{convert|120|in|mm}} per second provided high bandwidth and impressive time axis resolution. Later models replaced the mirror with a stationary fiber-optic cathode ray tube that was in direct contact with the paper.

These recorders had several flaws. The photo-sensitive paper was very expensive, and would quickly fade when exposed to ambient light. High chart speeds meant that test durations were extremely short. These instruments were intended to capture short-duration events such as [[NASA]] rocket launches in the 1960s and a broad range of ballistic events.