Absent a narrowing definition in the specification, the broadest reasonable interpretation of a “sub-signal” requires only slight differences between signal versions. Here, for example, given a broad description in the specification, the claimed “sub-signal” was correspondingly interpreted as reading on propagation-dependent versions of the same signal. It may therefore be best to include at least a dependent claim with a more specific definition of such terms if the specification is going to describe them broadly, especially when a narrowing definition has a particular (e.g., practical implementation) utility.
Background / Facts: The application on appeal here from rejection at the PTO is directed to variable bandwidth receivers having multiple antennas, in which different antennas are configured to selectively receive different “sub-signals” of a wideband signal. The specification broadly describes the potential relationship between the different sub-signals, which “may be spaced apart in the frequency domain, or may overlap,” “may be adjacent or non-adjacent,” and “may occupy different subchannels of a wideband channel.” The prior art discloses a multi-antenna receiver in which each receiver receives the same signal, but with slight variations due to natural changes in phase, power, and interference—that is, the received signals may differ from each other as a result of natural impairment during propagation.
Issue(s): Whether the broadest reasonable interpretation of a “sub-signal” in light of the specification here reads on propagation-dependent versions of the same signal.
Holding(s): Yes. “[W]hen received by the antennas, the versions of the signals [in the prior art] differed from each other due to natural impairment during propagation. Treating these differently impaired signals as sub-signals is consistent with the broadest reasonable interpretation of the term ‘sub-signals’ as used by [the applicant]. The specification nowhere expressly defines ‘sub-signal,’ and [the applicant] has failed to explain how the broadest reasonable interpretation of that term cannot include the wideband signal impaired during propagation. … Given such broad descriptions of sub-signal, the recognition of possible ‘overlap,’ and the lack of an express definition, [the applicant] cannot complain that the Board’s broadest reasonable interpretation includes two versions of a signal differently impaired during propagation.”