Application of John P. Mahony

421 F.2d 742, 57 C.C.P.A. 939
CourtCourt of Customs and Patent Appeals
DecidedFebruary 26, 1970
DocketPatent Appeal 8216
StatusPublished
Cited by4 cases

This text of 421 F.2d 742 (Application of John P. Mahony) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of John P. Mahony, 421 F.2d 742, 57 C.C.P.A. 939 (ccpa 1970).

Opinion

*743 LANE, Judge.

This is an appeal from the decision of the Patent Office Board of Appeals which affirmed the rejection of method claims 19 and 20 in appellant’s application serial No. 243,203, for- “Synchronizing Circuit,” filed December 5, 1962. Apparatus claims have been allowed.

THE DISCLOSURE

Appellant’s application relates to data communication systems and more particularly to circuits and methods for automatically synchronizing a receiver of digital information, such as a digital computer. The smallest unit of information in binary form is conceptualized, in information theory, as a binary digit, or bit. Like numbers and letters, bits are pure abstractions. To transmit the information bits, however, they must be represented in some physical form, as we shall later discuss.

The application discloses a method of synchronizing a receiver with a bit stream containing digital information. The bit stream of appellant’s disclosure is in the form of a sequence of electrical signals, each signal having one of two possible values. These values are designated 1 and 0 for convenience. A certain predetermined number of bits in sequence constitute a digital “word” corresponding to one printed character. In order for the receiving device to “know” where to divide the stream into words, a system of framing is employed, wherein each word consists of a certain number of information bits and a pattern of framing bits. The pattern of framing bits is always of the same value and in the same position relative to the information bits of each word. For example, words might be predetermined to have six bits each, with the first and sixth bits being framing bits of value 1 and 0 respectively, and the second through fifth bits being information bits which may be either l’s or 0’s according to the information they contain. Synchronization is the physical state of the receiver wherein it is set to receive the next bit as the first information bit of a digital word if that bit truly is the first information bit of a word. The receiver is “in sync” when the receiver “knows” where the bit stream should be divided to make words. Let us consider another simple example of framing, where each word is predetermined to consist of four bits, the first bit being the framing bit and the other three being information bits, and the framing bit is always of the same value, such as 1, whereas the information bits may be either l’s or 0’s. While the human mind cannot perceive bits in the form of electrical signals, we may, for the purpose of understanding the invention and the position of the Patent Office, represent a segment of a typical bit stream in visual character . form, as follows: 011000101110. Appellant has disclosed that one way of determining which bits in this stream are framing bits is to perform, by means of digital circuitry, a logical process of elimination. He disclosed a circuit comprising a shift register and various AND and OR circuits arranged to sample sequences of bits, each sequence having a number of bits equal to the number of bits known to be in a word. Of course, for the process to be carried out as disclosed by appellant, the bit stream must be in the form of electrical signals. In our second example, where there are four bits to a word and the framing bit is represented as a 1 at the beginning of each word, the circuit would be designed to sample various groups of four bits in order to determine which positions in the stream could not be framing bits. Appellant’s circuit in such an example would have a four-stage shift register, with each stage initially set at 1. The bit stream is fed through the shift register. A gate circuit is connected between the fourth stage and the input to the first stage. The gate is enabled to receive the next incoming bit if the fourth stage contains a 1. With the gate enabled, the shift register is capable of receiving the next bit as a 1 if it is a 1, but once a 0 occurs in any bit position that position will continue to register a 0 in future se *744 quences. A counter circuit is also provided, which in this case would count 0’s. When three successive 0’s are counted, it logically follows that the next bit will be a 1 and will be the framing bit. When this occurs, a gate to the receiver is enabled and the receiver is set to receive the beginning of a digital word. The disclosure does not show any other means for carrying out the logical process on the bit stream, nor does it suggest that the process could be performed mentally.

THE INVENTION

Both claims on appeal are method claims. Claim 19 is illustrative:

19. The method of establishing which bits in a bit stream are data bits and which are framing bits, where the framing bits appear in predetermined positions and have a predetermined sequence of values, comprising the steps of

(1) comparing to one another the values of bits in respective bit positions in successive equal length groups of bits,

(2) registering which respective positions in said groups of bits have a sequence of bit values inconsistent with said predetermined framing sequence as ascertained by repetitions of the comparing step, and

(3) counting the number of successive bit positions in the bit stream wherein the sequence of bit values has been ascertained as inconsistent with the predetermined framing sequence, whereby the framing bit positions are established when the number of successive bit positions counted is equal to the total number between the framing bit positions.

THE EXAMINER

The examiner rejected the appealed claims under 35 U.S.C. §§ 100 and 101 as being drawn to nonstatutory subject matter. He considered purely mental processes to be nonstatutory and regarded the claims as defining a purely mental process. The examiner demonstrated how the claimed process could be performed mentally based upon his understanding of • the terms in the claims. His position may be demonstrated by returning to our above example where a portion of the bit stream was represented as 011000101110, it being known that there are four bits to a word and that the first bit is a framing 1. The examiner would perform the elimination process by breaking the representation of the stream arbitrarily into groups of four bits each: 0110 0010 1110. In each group the first position is examined; it is seen to be not always a 1 and hence cannot be the framing position. The same can be seen regarding the second and fourth positions. The conclusion is that the third position must be the framing position. It is therefore known that in the portion of the bit stream represented, a word begins with the third, seventh and eleventh bits. While this knowledge might not be usable to any practical advantage, it was the examiner’s view that the claimed process had been performed.

THE BOARD

The board agreed with the examiner’s reasons and affirmed the rejection of the appealed claim under 35 U.S.C. §§ 100, 101. In addition, the board mentioned section 112, saying:

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Bluebook (online)
421 F.2d 742, 57 C.C.P.A. 939, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-john-p-mahony-ccpa-1970.