Device for detecting abnormalities in tape travel

摘要

A detecting device for detecting abnormality in the tape travel, comprises detectors for detecting capstan rotation pulses which have a frequency in accordance with the rotational speed of a capstan which drives and causes a tape to travel, supply reel rotation pulses which have a frequency in accordance with the rotational speed of a supply reel which pays out the tape, and take-up reel rotation pulses which have a frequency in accordance with the rotational speed of a take- up reel which takes up the tape, and a detecting circuit supplied with the three kinds of rotation pulses, for detecting abnormality in the tape travel and for producing an abnormality detection signal which indicates that an abnormality has been detected in the tape travel. The abnormality detecting circuit comprises a microcomputer for carrying out steps of counting the received capstan rotation detection pulses until a counted value of the capstan rotation pulses reaches a predetermined counted value, discriminating whether a supply reel rotation pulse was received during the counting period of the capstan rotation pulses, discriminating whether a take-up reel rotation pulse was received during this counting period, discriminating whether a capstan rotation pulse was received within a predetermined time period, and generating the abnormality detection signal when any one of the three discriminated results is "NO".