Signature analysis (digital technology)
In digital technology , signature analysis is a test procedure to check circuits for their correct function. Signals from circuit parts are collected over a longer period of time and a short bit vector (the signature ) is determined from them.
The correct functioning of the overall circuit is deduced from the comparison of this character string with a nominal value . In a test sequence, all single errors are recognized longer than the shift register length. For longer sequences, the error detection rate F becomes a function of the shift register length and results in F = 1 - 2 −n
Example: n = 16 → F = 1 - 2 −16 is round → 0.999985
Shift registers (LFSR) with linear feedback are often used to determine the signature .
Signature analysis includes the following variants:
- Multiple Input Signature Register (MISR): Parallel observation of several signals
- Build In Logic Block Observation (BILBO): Realization of different operating modes via additional multiplexers on the memory elements, whereby these can also be expanded using LSSD techniques, which results in a state-sensitive observation instead of an observation based on the edge steepness.
literature
- Christian Siemers, Axel Sikora: Taschenbuch der Digitaltechnik, ISBN 3-446-21862-9