Prior art — US Patent 7359437

The USPTO database search for patent number 7359437 would confirm the bibliographic data already provided in the patent text (title, assignee, inventors, filing date, issue date, and legal status). The patent US7359437B2 is listed as "Expired - Lifetime" with an expiration date of May 7, 2025.

The full text of US7359437 explicitly mentions two U.S. patents as prior art in its "Background of the Invention" and "Description" sections. These are:

U.S. Pat. No. 5,999,571
U.S. Pat. No. 6,151,334

Below is an analysis of each, including their full citations, relevant dates, brief descriptions, and potential anticipation of claims in US7359437 under 35 U.S.C. § 102.

Most Relevant Prior Art for US Patent 7359437

1. U.S. Pat. No. 5,999,571

Full Citation: U.S. Patent 5,999,571, "Data transmission system and method for synchronizing a receiver with a transmitter," issued to Jeffrey C. Banks et al. on December 7, 1999.
Publication/Filing Date: Issued: December 7, 1999. The patent text for US7359437 indicates it was issued on "Dec. 7, 1999".
Brief Description: This patent describes a data transmission system, such as a Transition Minimized Differential Signaling (TMDS) link, where code words indicative of video data are transition-minimized. During "preamble" periods when video data is not transmitted, synchronization words, which are distinguishable from the transition-minimized code words and can be transition-maximized, are transmitted. The patent teaches the consecutive transmission of several repetitions (e.g., three) of a synchronization word to allow the receiver's decoder to rapidly and accurately identify a specific transition for synchronization with the transmitter.
Potential Anticipation under 35 U.S.C. § 102:
- This patent broadly anticipates the concept of using distinct control or synchronization words during blanking periods. The idea of transmitting synchronization words that are distinguishable from data words, and potentially transition-maximized, aligns with the transmission of "out-of-band" words in US7359437.
- Specifically, this prior art may anticipate aspects of:
  - Claims 14 and 18 (Communication System and Method with Guard Band Words): While 5,999,571 uses "synchronization words" rather than "guard band words" in the context of ISI reduction, the function of marking specific transitions or periods by transmitting distinct, repeated words is similar. The repeated transmission of synchronization words to "identify a specific transition" and "accomplish synchronization" has functional overlap with the role of guard band words to "identify the leading and/or trailing edge of the burst".
  - Claims 22 and 25 (Communication System and Method with Different Guard Band Words for Data Types): Although 5,999,571 focuses on synchronization words during preamble periods and transition-minimized words for video data, it establishes the concept of different types of encoded words for different purposes (sync vs. data). This lays groundwork for using distinct markers for different data types, even if not specifically for ISI reduction.
  - The patent does not explicitly teach encoding data using a subset of code words specifically chosen for reduced ISI for data transmission, nor does it teach the concept of guard band words also encoding auxiliary data as described in some claims of US7359437.

2. U.S. Pat. No. 6,151,334

Full Citation: U.S. Patent 6,151,334, "Method and apparatus for transmitting multiple streams of data over a serial link," issued to Jeffrey C. Banks et al. on November 21, 2000.
Publication/Filing Date: Issued: November 21, 2000. The patent text for US7359437 indicates it was issued on "Nov. 21, 2000".
Brief Description: This patent details the transmission of several different types of encoded control words over a TMDS link, each distinguishable from transition-minimized code words used for data. These control words can include transition-maximized words. It introduces "data stream separation" words (to indicate the start or end of a data burst and its type) and "isochronous data transfer" words (synchronization characters indicating the type and beginning/end of blanking intervals, such as horizontal or vertical). The patent provides an example sequence: a first isochronous data transfer word (start of vertical blanking), a first data stream separation word (start of data in vertical blanking), a second data stream separation word (end of data burst), and a second isochronous data transfer word (end of vertical blanking). These control words are transition-maximized, while the data burst itself uses transition-minimized code words. It also describes a third data stream separation word before a stream of video data.
Potential Anticipation under 35 U.S.C. § 102:
- This patent directly anticipates the use of specific, distinguishable control words (like "data stream separation" and "isochronous data transfer" words) for marking the beginning and end of data bursts and blanking intervals, as well as indicating data types. These function as "guard band" words in a broader sense.
- Specifically, this prior art may anticipate aspects of:
  - Claims 14 and 18 (Communication System and Method with Guard Band Words): The "data stream separation" words and "isochronous data transfer" words explicitly serve to "identify the start or end of a burst" and "indicate the type of the blanking interval". This directly overlaps with the function of guard band words in US7359437 to "identify the leading and/or trailing edge of the burst".
  - Claims 22 and 25 (Communication System and Method with Different Guard Band Words for Data Types): The patent explicitly describes using different control words for different purposes, such as "isochronous data transfer" words for blanking intervals and "data stream separation" words for data bursts, and even distinguishing between the start/end of a blanking interval. This directly anticipates using "P different ... guard band words" where P >= 2, with "one guard band word for transmission at the start of each burst of encoded data of a first type... and another guard band word for transmission at the start of each burst of encoded data of a second type".
  - Claim 35 and 42 (Communication System and Method with Video/Auxiliary, ISI Reduction, and Specific Guard Bands): The prior art describes bursts of data (which could be auxiliary) within blanking intervals and video data in active periods, separated by control words. This sets the stage for distinguishing between video and auxiliary data bursts using different markers. However, it does not explicitly combine this with the inventive subset for ISI reduction or the detail that the video guard band word also encodes auxiliary data.
  - While it teaches the use of different types of code words (transition minimized for data, transition maximized for control/sync), it does not explicitly teach encoding data using a subset of transition-minimized code words specifically chosen for reduced ISI for the data itself, which is a core novelty of US7359437.

In summary, both U.S. Pat. No. 5,999,571 and U.S. Pat. No. 6,151,334 establish the foundational concepts of using distinct, specialized code words (synchronization or control words) to delineate data periods and synchronize transmission over serial links like TMDS. U.S. Pat. No. 6,151,334, in particular, details the use of different control words to mark the start/end and type of data bursts and blanking intervals, which strongly anticipates the "guard band word" concept of US7359437, especially concerning distinguishing between different data types. However, a key distinction of US7359437 lies in selecting an "inventive subset" of code words specifically for reduced ISI in the data stream itself, which is not explicitly taught by these prior art documents.