DATA EXTRACTING CIRCUIT AND DATA MULTIPLYING FORMAT CONVERTING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To make a circuit scale small by temporarily holding status information in two random access memories and status information or alarm information on a specific frame in another random access memory, and repeating subsequent extracting operation and writing and reading operation for the status information cyclically among the three random access memories. SOLUTION: A random access memory 1-3 and a random access memory 1-4 have planes switched with the write control signal of the alarm information. The random access memory 1-3 enters a write enable state when the logical level of a write enable signal is '0', so the random access memory 1-4 enters a write enable state when the logical level of the write control signal of the alarm information is '1'. The status information or alarm information S/A multiplied in an Nth frame among 1st multiple frames are written to the memory 1-3 when the logical level of the write control signal of the alarm information is '0'.