Appeal Number: 2006-1385
Application Number: 10/452,753
variety of sources including vehicle ignition systems (col. 10, ll. 20-29). Shridhara
further explains that once the jamming signal is detected, one or more
“countermeasures” are applied to reduce the effects of the jamming signal
(col. 4, ll. 26-31). Although Shridhara’s countermeasures include disabling the
GPS receiver input/output, notifying the user of the jamming signal, or applying
alternative position determination methods (col. 4, ll. 58-67), we do not find any
suggestion for reducing the jamming signal with a blanking signal having a pattern
similar to and synchronized with the jamming signal.
Turning to Beesley, we find that the reference is directed to noise blanking in a
radio receiver (p. 1, ll. 1-6). Beesley discloses a blanking signal that controls a
blanking circuit—an attenuator—for reducing the effects of noise pulses due to a
vehicle’s ignition system (p. 1, ll. 7-10). Beesley explains that a pulse detector
detects the presence of a jamming (noise) signal in the received signal (p. 1, ll.
81-84). After detection, the pulse detector determines certain characteristics of the
jamming signal, including the amplitude (p. 2, ll. 51-53) and rate of arrival (p. 3, ll.
104-107). A blanking signal is then generated based on these characteristics (p. 1,
ll. 56-61). Beesley explains that the purpose of generating a blanking signal based
on the characteristics of the jamming signal is to produce an optimized blanking
signal that effectively reduces the jamming signal (page 2, lines 82-87).
From our review of Beesley, we agree with the Examiner that Beesley teaches
a blanking signal having a pattern similar to a jamming signal. The two signals are
similar because the amplitude of the blanking signal is adjusted depending upon
the amplitude of the detected jamming signal.
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