Control systems for magnetic recording tapes

Abstract

Methods and apparatus for recording information with a magnetic recording head advance magnetic recording tape from a first rotating tape coil into a second rotating tape coil and assure constant head-to-tape contact with constant tape tension independently of variations in coil diameter and in tape velocity. There is determined or stored, for a series of diameter ratios between the first and second tape coils, a series of corresponding values of the first and second tape drive control signals for effecting advancement of the magnetic recording tape relative to the magnetic recording head with the first and second tape drives at constant head-to-tape contact with constant tape tension for all diameter ratios of that series. An electric third signal indicative of instantaneous diameter ratio between the first and second tape coils is provided in response to first and second tape coil tachometer signals. For each diameter ratio of that series, those of the corresponding values of the first and second control signals which effect advancement of the magnetic recording tape at constant head-to-tape contact with constant tape tension at the particular diameter ratio, are selected in response to the electric third signal, and the tape drives are continually controlled accordingly.