| 摘要 |
<p>PURPOSE:To obtain a trigger circuit having a long random cycle length by providing the 1st and 2nd ROMs as read only memories to which a uniform random value is written and an operation device operating contents of the two ROMs and obtaining a uniform random output value. CONSTITUTION:The titled device is provided with an adder 8 inputting content of outputs of the 1st ROM5 and the 2nd ROM7 and a discriminating circuit 9 checking whether or not the content of bits except carry is within a specified range among outputs of the adder. The input of the discrimination circuit 9 is (1110) and a ''false'' signal is outputted with the relation of 1110>=1100. Since a register 10 does not fetch this data but hold the preceding trigger period data, the generated trigger period the same as the preceding period is unchanged. The content of the 3rd counter 4 becomes (0000 0010). Then the discriminating circuit 9 generates a ''true'' signal, which is fetched by the register 10 and becomes a preset data of the 2nd counter 3. Thus, the trigger pattern of a long period is obtained.</p> |
