Invalidity dossier
US 5870425
Differential receiver of direct sequence spread spectrum signals
Current assignee: Xantima LLC
Added 9/23/2026, 8:36:47 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,870,425
Title: Differential receiver of direct sequence spread spectrum signals
Patent number: US 5,870,425 (application US08/747,260)
Inventors: Bernard Piaget, Charles Fort, Patrick Le Masson
Original assignee: Commissariat à l'Energie Atomique (CEA). The source lists a current assignee of Xantima LLC, but the excerpt does not establish the transfer's terms.
Key dates (as listed): Priority date 1995-12-07; filing date 1996-11-12; publication/grant 1999-02-09; anticipated expiration 2016-11-12. Status: Expired – Lifetime. The source states legal status is an assumption and not a legal conclusion.
Purpose: The invention addresses a problem in conventional direct sequence spread spectrum (DSSS) receivers. The introductory text explains that a known receiver (radio frequency stage, frequency change stage, intermediate frequency "FI" stage, and baseband restoration stage, the latter using a correlator, delay line, multiplier, integrator and comparators) can suffer errors when the antenna intercepts jamming or interference whose spectrum falls within the pass band of the RF and FI amplifiers. The stated object is to obviate these disadvantages.
Plain-language scope: Rather than one conventional FI stage, the invention proposes an FI stage made up of several channels, each responsible for processing part of the spectrum. A summating stage collects the channel signals to recompose the signal with its normal spectrum. Each channel has a band filter, at least one adjustable-gain amplifier, and automatic gain control. The excerpt indicates that if the conventional FI stage delivers power P, each of N channels i supplies approximately a power pᵢ, but the governing equation is truncated in the supplied text.
What the excerpt does not establish: The full claims and their exact language; dependent-claim structure; the complete mathematical relations; the detailed description of channel summation; the FR-A-2 696 298 prior document's contents beyond citation; and any litigation, validity, or ownership-transfer details.
Generated 10/1/2026, 9:41:16 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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