Distortions of magnetic recording, caused by magnetic tape deterioration

Magnetic recording is often used for signal registration in field observations. Measuring equipment and magnetic tape are subjected to hard usage and storage. At the same time some unique magnetic tapes are required to be kept long time. Typical distortions of magnetic recording caused by deterioration of magnetic tapes, and sources of distortions are considered in the paper. Such typical distortions are (1) transfer ratio decreasing for direct recording caused by wastage of magnetic layer, (2) amplitude and phase signal modulation caused by start-stop operations, (3) signal losses caused by adhesion disruption in tape. Some techniques for evaluation of archival magnetic tapes condition and recommendations on distortions decreasing are presented.