| 摘要 |
PROBLEM TO BE SOLVED: To improve the safety by obtaining a 1st cyclic redundancy check value(CRC) from a data signal by a CRC circuit and comparing it with a 1st CRC reference value by a 1st comparing circuit, and generating and latching a blanking signal at its output terminal when the values are not equal to each other. SOLUTION: Video pixel data 30' are processed by the CRC circuit 60, which generates the 1st CRC value. With a 32×16×2 pattern, a 15-bit CRC value can be generated and a security device 100 is enabled to use one 24-bit register as a 1st memory 62 of CRC standards. The comparing circuit 64 compares the 1st CRC value with the 1st CRC reference value. When the 1st CRC value and 1st CRC reference value are not equal to each other, the comparing circuit 64 generates an unequal signal. In response to the unequal singal, a control circuit 66 generates a D/A blanking signal 32 and latches it. |
