Keysight Technologies, Inc.
Real time trigger using a finite state machine having a counting state

Abstract:

An apparatus that searches for a pattern in a signal is disclosed. The apparatus can be used to implement a real time trigger in an instrument such as a high speed oscilloscope. The apparatus includes a symbol generator and a finite state machine (FSM). The symbol generator receives an ordered sequence of signal values and converts the ordered sequence of signal values into an ordered sequence of symbols, each symbol having a plurality of states. The FSM receives the ordered sequence of symbols and generates a match signal if the ordered sequence of symbols includes a target sequence specified by a regular expression that includes a counting limitation on one of the symbol states. The FSM includes a counting state that includes a counter that counts instances of the one of the symbol states.