Device for protecting the validity of time sensitive information
US5489095A · kind A · utility
48Cited by
6References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 23, 1993 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Jun 23, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2207/7219
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The clock circuit is formed by an oscillator (10-12) which is coupled to a counter/divider circuit (15) provided with read accesses (30). In order to prevent falsification of its data, the circuit is formed as a protected casing and includes a protected access circuit (50) which is connected between said accesses and the counter/divider circuit. Furthermore, a circuit for monitoring the frequency of the oscillator may be provided (100-50).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.