| 摘要 |
<p>PURPOSE:To flexibly cope with various modifications of specifications by calculating the difference between a new and an old counting data fetched in accordance with an instruction from a microcomputer, discriminating the recording speed of the magnetic tape based on the result of this calculation and a running speed command value for magnetic tape. CONSTITUTION:An instruction execution circuit PLA 1400 controlling the operation of a 16-bit arithmetic unit ALU 1300 that executes a logical operation, checks whether the leading edge of a reproduced control signal has reached or not, and if reached, the circuit PLA makes the ALU 1300 calculate the difference between the counting data tn-1 fetched precedently in a specific address of a RAM 1200 and that tn newly fetched, and records the result in an accumulator ACC that is remained in a register 1100 as a calculated value for interval. Then, the PLA 1400 checks which one of the three modes the running time mode at present point of time held in the RAM 1200 is; depending on the result, advance the processing to varied sequences, and thus controls the running phase of the magnetic tape. As a result, various modifications of specifications can cope with flexibly.</p> |
