J. Takeuchi et al., A STUDY ON THE INTERCHANGEABILITY OF THE CENTER-ROTATING DRUM VCR, IEEE transactions on consumer electronics, 41(4), 1995, pp. 979-985
A new method to measure tape motion on the helix guide of the drum was
developed. As a result, real-time and high precise observations were
accomplished, accordingly, the optimum mechanical conditions were deci
ded and good track straightness was achieved.