| 摘要 |
PURPOSE:To automatically detect a point where address data changes and to renumber addresses in full automation by sequentially reproducing recorded address data and comparing the sizes of pieces of data around the reproduced data. CONSTITUTION:In the quick forwarding mode of a VTR, a control head 4 sequentially reproduces control pulses on a tape. They are supplied as pulses (b) to a microcomputer 1 and a decoder 10 through a trigger circuit 9. The circuit 10 transmits demodulated data of 16 bits to the microcomputer 1 by eight bits according as the address data in a register 21 agrees with just before address data in a comparator 22. When the microcomputer 1 detects an address code, it compares a current address with a previous one in terms of magnification. When the current address is larger, the microcomputer 1 judges that the operation is normal; otherwise, it judges abnormal. At that time the microcomputer 1 stops the tape from traveling. After the VTR is set in a rewinding mode, the microcomputer 1 detects a header in the address code whose program searching reproduction starts, varies the duty of a control pulse in the order of the address data at the detection point, and reproduces and records data.
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