Appeal No. 2006-0406
Application 09/497,865
Chang, which shares one of the co-inventors of the present
application, is mentioned by appellants at page 11 of the
specification and is assigned to the real party in interest of
this application. Chang discloses a circuit in Fig. 2 which
corresponds to Figs. 4 and 5 of appellants, except that the
output of the DBF 130 is not sent to code generators 58 and a
multiplexer 60 and a digital receiver 64 as in Fig. 5; however,
these differences in circuitry are not claimed. The low noise
amplifier 142 in Chang have a low noise amplifier and a band pass
filter (BPF) corresponding to elements 38 and 40 in Fig. 4, and
the decoder 202 contains matched filters corresponding (col. 6,
lines 35-37) to the match filters 52 in Fig. 5, although band
pass filters and matched filters are not claimed. There appears
to be no dispute that Chang teaches the "multiplexer," "analog to
digital converter," "circuitry for forming multiple digital beams
corresponding to respective coded element signals from said
digital bit stream." Appellants do not dispute the examiner's
finding that the one or more output beams B inherently go to a
digital receiver. Appellants argue that Chang does not teach the
use of coding for retrodirectivity, i.e., the strongest signal is
not determined so that a transmitting beam may be transmitted
using the same element (Br5). Chang does not expressly disclose
selecting a strongest signal, but, given the teachings in Chiba,
we find that one of ordinary skill in the art would have known to
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