Digital tiggering using finite state machines

摘要

An apparatus that can be configured for various functions such as a digital oscilloscope, logic analyzer or frequency analyzer is disclosed. The apparatus includes a symbol generator, a multi-symbol FSM, and a controller. The symbol generator generates an ordered sequence of symbols from an ordered sequence of digital values. The symbol generator generates one symbol corresponding to each of the digital values. The digital values have a greater number of possible values than the symbols. The controller causes the multi-symbol FSM to search for a pattern in the sequence of symbols that identifies a corresponding pattern in the sequence of digital values. A portion of the digital sequence is then displayed based on the location of the pattern in the sequence of symbols.

主权项

1. An apparatus comprising:
an input port configured to receive an analog signal that varies as a function of time and to generate an ordered sequence of digital values therefrom; a symbol generator that generates an ordered sequence of symbols from said ordered sequence of digital values, said symbol generator generating one symbol corresponding to each of said digital values, wherein said digital values are characterized by a number of possible digital value states and said symbols are characterized by a number of possible symbol states, said number of possible symbol states being less than said number of possible digital value states; and an FSM characterized by an input word, and a plurality of FSM states, said FSM changing from a current one of said plurality of FSM states to another one of said plurality of FSM states that is determined by said input word and said current one of said plurality of FSM states in response to a cycle signal being received; a controller that causes said FSM to search for a pattern in said ordered sequence of symbols, said controller loading said input word with a plurality of said symbols, generating said cycle signal, and coupling said cycle signal to said FSM.