Diagnostic support within a digital tape recorder

One major problem in a digital tape recorder is that the oscillogram of a digital signal will not necessarily provide an indication of the type of fault involved; this means that conventional analog techniques are not sufficient for trouble shooting. Due to digital processing, the signals are more complex than with analog technology. Possibly the signals are embedded in additional error protection coding. Therefore it is not easy to construct the original source signal for error evaluation. Because of these problems and the high degree of complexity of a tape recorder, measurement methods and diagnostic techniques were integrated into the DCR100 tape recorder to support the maintenance personnel. From the point of view of maintenance a digital recording system can be divided into three parts. The head/tape system, the digital signal processor and the control system