Appeal No. 2003-1663 Application 09/975,934 a logical "true" (conventionally represented as "1"), the output is a logical "true" ("1"), and when one or more inputs are a logical "false" (conventionally represented as "0"), the output is a logical "false" ("0"). An "AND" operation is, by definition, a "logical" operation, so "AND logical" to describe a circuit is redundant. An "AND" operation is also, by definition, a function, so "AND functional" to describe a circuit is redundant. The terms "AND circuit," "AND logical circuit," "AND functional circuit," and "AND logical functional circuit" all have the same meaning. An "AND" operation necessarily implies operation with digital signals, i.e., signals that represent either a "1" or a "0." An analog circuit which performs an AND function has to be operating using digital logic signals, i.e., with signals that the circuit interprets as "1" or "0"; it does not make sense to define an "AND" operation in terms of analog (continuous) signals. The statement in Digital Integrated Electronics that "[i]n logical gates all inputs and outputs are digital signals," only refers to the digital data representation and does not imply anything about the implementation of the logic circuits. Appellants may be confusing digital signals with the circuitry that implements the signals. While there are some logic implementations that could be considered pure digital (e.g., a switch which is either closed or open), there are many logic implementations that use analog devices to produce signals - 6 -Page: Previous 1 2 3 4 5 6 7 8 9 NextLast modified: November 3, 2007