Effect of Tape Longitudinal Dynamics on Timing Recovery and Channel Performance

The recording performance is compared for two barium ferrite magnetic recording tapes which differ by a factor of two in friction, but are otherwise very similar. The error rate of the tapes is similar at a tape speed of 4 m/s, but as the read or write speed decreases to 1.16 m/s, the error rate of the smoother, higher friction tape increases by a factor of 100. This effect arises from velocity variations in the tape, which prevent accurate timing recovery and uncertainty in the phase of the recorded waveform. The velocity variation is measured by recording a periodic waveform. Its power spectrum demonstrates the effect of the compressional sound wave resonating between rollers on either side of the recording head.