The Federal Circuit held that the Patent Trial and Appeal Board (PTAB) is not permitted to cancel claims on the grounds of indefiniteness in an inter partes review proceeding. However, even if certain claims are found to be indefinite, the PTAB may still rule on the patentability of the indefinite claims under 35 U.S.C. 102 and 103.
Also, the term "digital processing unit" is not a means-plus-function limitation subject to analysis under 35 U.S.C. 112, paragraph 6. The court stated that [as used in this patent] the term "digital processing unit" clearly serves as a stand-in for a "general purpose computer" or a "central processing unit," each of which would be understood as reference to structure in this case, not simply any device that can perform a particular function.
Read the case here.