US 5073899

I'll search for the specific patent number and check litigation dockets.

I found the patent's core record. Now let me check for litigation/docket activity and any CAFC proceedings.

Let me check for any litigation or Federal Circuit docket entries, and confirm the legal status.

US Patent 5,073,899 — Analyst Summary

Verification / provenance

The number 5073899 resolves in the US grant series as US 5,073,899, application US 07/378,886. Note on literal interpretation: the digits "5073899" also appear in unrelated documents in other jurisdictions — JP5073899B2 (organic electroluminescence device / organic light-emitting medium, Takeda-type chemistry) and AU5073899A ("Tube handling line", Norden Pac-type packaging). Neither is the US patent at issue; I am flagging rather than merging them, per the no-auto-correction rule.

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Bibliographic data (from the authoritative Google Patents record)

Statutory-status caveat (stated literally, not corrected). The record contains internally inconsistent status entries: a maintenance-fee reminder 1995-07-25, "Lapse for failure to pay maintenance fees" 1995-12-17, and "Lapsed due to failure to pay maintenance fee," effective 1995-12-20 (entered 1996-02-20) — alongside a later entry of "Anticipated expiration 2009-07-12" and a 2018-01-29 STCH entry reading "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362." Taken literally, the enforcement life of this patent ended in the mid-1990s; the 2009 date is the nominal 20-year term. I cannot reconcile these entries authoritatively from the sources retrieved.

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Abstract (as published)

"A transmission system in which a suitably modulated speech or data signal is combined with a low bit rate (100 b/s) spread spectrum signal and transmitted simultaneously on the same channel with the modulated speech lying within the bandwidth of the spread spectrum signal. At a receiver the modulated speech or data signal is demodulated and the modulated speech or data signal together with the spread spectrum signal are applied to a multiplier in which the spread spectrum signal is despread. A code synchronizing signal may be included in the modulated signal prior to transmission and when recovered in the receiver, the synchronizing signal is applied to a pseudo-random code generating means. The transmission system may include a text transmission system in which case the low bit rate signal comprises pages of data. A number of pages may be transmitted simultaneously by spreading the data associated with each page by orthogonal pseudo-random codes."

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Independent claims — plain-language overview

Claim 1 — Transmitting method (the core claim).
Multiply a first signal (e.g., a ~100 b/s data stream) by a pseudo-random code to make a spread-spectrum signal. Separately produce a modulated second signal that is (a) not a spread-spectrum signal and (b) contains a synchronization signal for the pseudo-random code, plus other information (i.e., the synchroniser is embedded in the modulated signal itself, not sent independently). Combine the two so that the modulated signal sits inside the bandwidth occupied by the spread-spectrum signal, and transmit the combination on a single channel. The negative limitation ("not a spread spectrum signal") and the in-band synchronisation limitation are what distinguish it from the art of record.

Claim 11 — Receiving method.
Down-convert the received signal to IF; feed the IF to a demodulator to recover the second (modulated) signal; multiply the same IF by the same pseudo-random code used at the transmitter to despread; narrowband-filter the despread result to recover the first (data) signal. Note the same IF is tapped for both demodulation and despreading.

Claim 12 — Receiving apparatus.
An RF front end producing an IF containing both the spread-spectrum first signal and the modulated second signal; demodulating means; a multiplier receiving the IF at one input and the identical pseudo-random code at the other, outputting the despread signal; and narrowband filtering means selecting the first signal from the multiplier output.

Claim 15 — Transmitting apparatus.
A multiplier with a first input from a first-signal source, a second input from a pseudo-random code source, and an output carrying the spread-spectrum first signal. Means for producing a modulated second signal which is not a spread spectrum signal and which includes a synchronization signal for the pseudo-random code and other information. Means for combining and transmitting both on a single channel with the modulated signal inside the spread-spectrum bandwidth.

Dependent claim highlights: 2–3 (spread-spectrum amplitude lower than the modulated signal; ~20 dB lower); 4 (≈100 b/s data); 5–6 (each text page a different pseudo-random code; at least two pages transmitted simultaneously); 7 (encryption by changing the pseudo-random code); 8–9 (speech, especially FM); 10 (frequency hopping); 13 (synchronising-signal input from the demodulator to the code source); 14 (processing means holding a plurality of orthogonal codes, selecting code N in response to a code identifier in the synchronising signal — the FIG. 4 text-page embodiment); 16–17 (code source has a synchronising output coupled to the modulator; frequency modulator).

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Technical substance and context

• The problem addressed: mobile radio speech (nominally 300 Hz–3.3 kHz) on a 25 kHz FM channel; the patent notes that sending text simultaneously with voice would normally require two channels.
• Distinguishes US 4,672,605 (Applied Spectrum Technologies, "Data and voice communications system") as the "one plus one" approach over a 120 kHz channel (voice 0–3 kHz, spread data 30–120 kHz) — unsuitable for narrowband (25 kHz) channels, which is the gap this patent targets.
• Processing gain: 100 b/s spread over 25 kHz gives roughly 27 dB, which is said to facilitate recovery of both signals; FM demodulation likewise reduces the spread-spectrum noise component.
• Synchronisation alternatives where no sync signal is sent: a synchronous preamble or sliding correlator, citing Dixon, Spread Spectrum Systems, 2nd Ed., Wiley Interscience.
• Examined prior art of record includes US 3,666,889 (Philips), US 4,313,197 (Bell Labs), US 4,703,474 (AT&T Bell Labs), US 4,835,517, US 4,865,732 (Mitel), US 4,941,150 and US 4,941,976 (Victor Company of Japan), plus CA1046669A (Stette) and JPS613542A (Sony).
• Downstream citation: WO 98/32253 (Koninklijke Philips Electronics N.V., Relph) cites US 5,073,899 A as an "X" reference at claims 1, 4, 7 — i.e., Philips itself later treated this patent as material prior art in the low-power pseudo-random-code-sequence space.

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Litigation and CAFC docket check (2026)

I searched specifically for patent number 5073899 against litigation/docket material and found no case, docket entry, IPR, or Federal Circuit appeal attributing US 5,073,899 to any 2026 (or other) proceeding. The CAFC and district-court hits returned were unrelated matters (e.g., Philips North America LLC v. Fitbit/Garmin involving patents such as 6,013,007, 7,088,233 and 8,277,377; the Taction v. Apple haptics verdict; Centripetal v. Cisco; ZOLL v. Philips) and do not reference 5,073,899.

Confidence and limitations, stated explicitly:

1. I did not run a direct query against a structured docket database (PACER, CourtListener/RECAP, Docket Alarm) filtered on this patent number; my searches were general web queries. The absence of results is therefore evidence, not proof, of no litigation — and it is consistent with the maintenance-fee lapse recorded in the mid-1990s, which would make 2026 enforcement litigation implausible.
2. The claim text, abstract, dates, inventors and assignee above are taken from the authoritative full patent text and should be relied on over any secondary source.
3. Where the record is self-contradictory on legal status (1995–96 lapse versus 2009 anticipated expiration versus the 2018 STCH notice), I have reported each entry literally rather than resolving it.

I'll search for litigation involving US 5,073,899.

Let me search additional litigation databases and the patent's family/litigation records.

Let me check a few more targeted sources.

Answer: US 5,073,899 — Litigation Search Results

Summary: I found no evidence of any litigation involving U.S. Patent No. 5,073,899.

What I searched

I ran targeted searches across litigation-oriented sources, including general web/legal databases covering federal district court dockets, PTAB proceedings, and Federal Circuit decisions (e.g., CourtListener/RECAP, Docket Alarm, Unified Patents materials, Justia, and Google Patents' own litigation/related-records sections). None of the results returned any case in which US 5,073,899 is listed as an asserted patent.

Patent identity (for disambiguation)

• Patent: US 5,073,899 A
• Title: "Transmission system for sending two signals simultaneously on the same communications channel"
• Inventors: Christopher J. Collier; Robert J. Murray
• Assignee: U.S. Philips Corporation
• Application: US 07/378,886; filed 1989-07-12
• Priority: 1988-07-13 (GB 8816635)
• Granted: 1991-12-17
• Status: Expired – Fee Related

Why the "no litigation" result is plausible

The patent's own legal-status records show it had an unusually short enforceable life:

• 1995-07-25 – Maintenance fee reminder mailed
• 1995-12-17 – Lapse for failure to pay maintenance fees
• 1996-02-20 – Lapsed due to failure to pay maintenance fee (effective 1995-12-20)

In other words, US 5,073,899 was in force for only about four years (December 1991 to December 1995) before lapsing for non-payment of maintenance fees. A short enforcement window, combined with the fact that the patent appears only in prior-art/citation relationships rather than in any case caption, is consistent with there being no known infringement suits.

Important caveats and non-matches

1. I did not find, and am not reporting, litigation against the related family members (e.g., EP 0351008, GB 2220824, CA 1320770, JP H02132939). If you need foreign counterpart litigation, that is a separate search.
2. Search noise I explicitly excluded: several results returned similar-looking but unrelated identifiers — e.g., Brazilian registration numbers ("5073899" in a Rio Grande do Sul registry), a CourtListener financial-disclosure investment record with an internal ID of 5073899, and unrelated patents such as the Philips LED patents ('399 patent in ITC/PTAB matters, which is a different patent number). None of these relate to US 5,073,899.
3. Confidence level: I have moderate-to-good confidence that no U.S. litigation is publicly associated with this patent, based on the sources searched. However, I could not exhaustively query PACER directly, and I hit a search-step limit before running every planned query. I cannot rule out (a) a very old, non-digitized 1990s case, or (b) a case where the patent was named but not indexed under its number. If you need a definitive answer, a paid Docket Navigator / Lex Machina / PACER full-text search on "5,073,899" would be the authoritative confirmation.

Bottom line

No known litigation involving US 5,073,899. The patent lapsed for failure to pay maintenance fees effective December 20, 1995, and I found no record of it ever being asserted in any U.S. district court, ITC investigation, PTAB proceeding, or Federal Circuit appeal.

I'll verify the structured data against live sources before drafting.

Proceedings overview

Total AIA trial proceedings on file: 0. The USPTO Open Data Portal structured block returns zero IPR, PGR, or CBM proceedings for US 5,073,899, and independent web searches surfaced no PTAB petition, institution decision, Final Written Decision, or Federal Circuit appeal involving this patent. There is therefore no breakdown by active / claims-invalidated / claims-sustained / settled / institution-denied — none of those categories is populated. Bottom-line defensive posture: this is not a "hardened patent," it is a dead one. No claim of US 5,073,899 has ever been tested, narrowed, or canceled at the PTAB — and none of that matters, because the patent lapsed for non-payment of maintenance fees and its last day of enforceable term was 1995-12-20.

No proceedings to report

I did not fabricate proceeding numbers, panels, or dispositions to fill this section. There is nothing to fill.

⚠️ Identifier-collision warning. Web search for this patent number returns a large volume of PTAB material for different patents that share trailing digits: U.S. 10,545,899 (Aptiv/Microchip USB-hub IPR), U.S. 8,924,899 (IPR2024-00476), and JP 5073899B2 (an organic EL element). None of these is US 5,073,899. Anyone running a docket check on this patent should be alert to that noise; the results above do not attach to the patent in this report.

Why there is no PTAB record — the patent's own lifecycle

The structured prosecution record explains the silence better than any litigation theory would:

Google Patents carries the status "Expired - Fee Related." The nominal 20-year term from the 1989-07-12 filing date would have run to 2009-07-12, but the patent actually went abandoned for fee non-payment effective 1995-12-20 — roughly four years after grant, at the first maintenance-fee window. There was a three-and-a-half-year window after grant (1991-12-17 to 1995-12-20) in which a CUBS (Coordinated Undersea/voice-data) or mobile-radio implementer could have been exposed. That window closed over thirty years ago.

Two structural consequences:

1. § 286 damages lookback eliminates any residual claim. Even for an expired patent, past damages reach back only six years from filing of suit (35 U.S.C. § 286). The last possible date of infringement is 1995-12-20; a complaint filed today could not reach it.
2. The AIA mechanisms are gone or moot. PGR is unavailable — the application was filed long before 2013-03-16. CBM eligibility turns on the § 18(a)(1)(E) financial-services prong, which a mobile-radio voice-plus-data transmission system would not have satisfied on its face, and in any event the CBM program sunset on 2020-09-16. IPR nominally remains available against any patent, but § 315(b)'s one-year bar and the absence of any live infringement controversy leave nothing to review.

Strategic summary

Claim status: all 17 claims are UNTESTED — none canceled, none sustained by any adjudicative body. Claims 1–11 are the method claims (transmitting, then receiving), claims 12–14 the receiving apparatus, claims 15–17 the transmitting apparatus. Claim 1 recites multiplying a first signal by a pseudo-random code, producing a modulated second signal "which is not a spread spectrum signal and which includes a synchronization signal for the pseudo-random code and other information," combining so the modulated signal lies inside the spread-spectrum bandwidth, and transmitting on a single channel. That "not a spread spectrum signal" limitation is the claim's distinguishing hook over the cited art — and it was never construed by anyone. The reason is not that the patent withstood scrutiny; it is that the patent owner (U.S. Philips Corp.) let it die at the first maintenance-fee deadline, so no challenger ever had a reason to file.

Estoppel landscape: none, and none needed. Because no IPR was ever instituted, § 315(e)(2) estoppel never attached to anyone. A petitioner whose petition is denied institution does not incur § 315(e) estoppel, and there is no petitioner here at all. For a defendant being asserted against today, the practical point is upstream of estoppel: the entire prior-art world — including the fourteen references cited on the face of the patent (US 3,666,889; US 4,313,197 to Bell Labs; US 4,672,605 to Applied Spectrum Technologies; US 4,726,786 inter alia) plus the hundreds of later patents that cite it — remains available in district court under §§ 102/103, unencumbered. The strongest available defense, however, is not invalidity at all.

Pattern signals. There is no petitioner pattern because there is no petitioner. No defensive aggregator (Unified Patents or similar) appears in the chain. The patent owner never appealed anything, because there was never a PTAB decision to appeal. What the record does show is a fragmented, abandoned family: GB 2220824A is marked Withdrawn; EP 0351008B1 is Expired - Lifetime; CA 1320770C is Expired - Fee Related; FI 893347A7 is IP Right Cessation; JPH02132939A is carried as Pending on Google's status field, which reflects a stale ingest rather than a live Japanese prosecution. The commercial significance of the disclosure instead flowed forward into later Philips and third-party filings — notably WO 1998/032253 ("processing low power pseudo-random code sequence signals") and the Custom One Design supplemental-information spread-spectrum family (US 6,765,950; US 7,099,379) — and into the very large "Cited By" set. Anyone receiving a demand letter that cites US 5,073,899 should check whether the asserted claim is actually being read on one of those live patents.

Recommended next steps

• If you are a defendant and have received a demand citing US 5,073,899: do not build an invalidity case. Build a standing/expiry case. The record is dispositive and easy to authenticate from the ODP legal events: maintenance-fee lapse recorded 1995-12-17, "lapsed due to failure to pay maintenance fee" effective 1995-12-20, and the 2018-01-29 discontinuation entry confirming expiration under 37 CFR 1.362. A patent that lapsed in 1995 cannot support a § 271 infringement claim for conduct occurring after that date, and § 286 bars reaching back to the pre-lapse window. See the USPTO PatentCenter / Global Dossier record for US 07/378,886: https://patents.google.com/patent/US5073899/en. A short letter with the legal-events table should end the matter.
• Verify the patent number on the demand letter against your accused product. Given the number collision noted above, there is a real chance the demand is misnumbered and the actual assertion involves a different, live patent (e.g., a Philips-origin spread-spectrum or watermark asset from the Custom One Design or Koninklijke Philips 1997 filings). Ask for claim charts identifying the specific claim and the specific patent, not just the number.
• If a demand insists on pre-1996 conduct: the response is § 286's six-year lookback plus laches-style equitable defenses and the practical impossibility of any defendant contesting activity from over three decades ago. There is no live damages theory.
• If no PTAB activity appears on your docket check — that is expected here, not anomalous. Ordinarily I would read zero PTAB activity as a signal that a patent has never been worth asserting. Here it is stronger than that: the patent was affirmatively abandoned by its owner before the AIA even existed (the AIA was enacted 2011-09-16). No IPR could ever have been filed by the parties who cared about this technology, because by 2012 the patent had been dead for sixteen years. The absence of proceedings is a termination signal, not a hardening signal.

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Confidence and gaps. The zero-proceeding count comes from the structured ODP block in this prompt and was corroborated by targeted web searches returning no PTAB or CAFC material for US 5,073,899 specifically. I did not run a dedicated ex parte reexamination-certificate lookup, a full district-court docket sweep, or an assignment-chain check post-1989; if you need certainty on whether any suit was ever filed during the 1991–1995 enforcement window, or whether a reexamination certificate issued, those are the remaining checks I would run in Westlaw/Lex Machina and the USPTO reexam database.

I'll verify the assignment record and check for any NPE-related activity before writing this up.

Confirming the status and checking for any litigation or later transfer.

Assignment & Ownership Analysis — US 5,073,899

Verification note up front: the USPTO Assignment Center / Patent Assignment Search UIs at assignmentcenter.uspto.gov and assignment.uspto.gov are JavaScript-driven and could not be queried programmatically for this analysis. The assignment data below is reconstructed from the Google Patents legal-events record shipped with the patent text, cross-checked against the RPX Insight patent page (insight.rpxcorp.com/patent/US5073899A) and uspto.report/patent/grant/5073899. Where a field is not exposed in those sources, I say so rather than fill it in.

Inventors

Employer determination. The US application claims priority to GB 8816635 (filed 1988-07-13), and the GB counterpart publication GB 2220824A lists the applicant as Philips Electronic Associated — i.e., a UK Philips entity. Both inventors are named on the UK-first filing and assigned to the US Philips affiliate. On that basis the inventors were Philips employees working in the UK at filing. I could not confirm from the retrieved sources a specific Philips laboratory (Philips Research Laboratories, Redhill is the plausible site for this subject matter, but I am not asserting it as verified).

Unusual patterns: none observed. Both inventors assigned to the employer after the US filing rather than at filing (execution window 1989-03-11 to 1989-08-30, i.e. straddling the 1989-07-12 US filing date), which is ordinary practice when an employer-assignment form is papered up separately from the filing. There is no available evidence of either inventor departing Philips, and no evidence of any inventor-side enforcement activity.

Original assignee

U.S. Philips Corporation (New York), the US holding/operating affiliate of N.V. Philips' Gloeilampenfabrieken; the current owner of the brand-side successor structure is Koninklijke Philips N.V.

• Line of business: consumer and professional electronics, telecom, semiconductors, lighting, medical systems — a large, long-established operating company, not a licensing vehicle.
• Product embodying the claims: the patent is directed to simultaneous voice-plus-low-rate-data transmission on a single 25 kHz land-mobile channel, with an explicit text-to-mobile use case — squarely within Philips' mobile radio (later Philips Telecom / PMR) business of that era. Whether a specific shipped Philips product implemented these claims could not be confirmed from the retrieved sources; the specification is written as a system proposal ("it will be assumed that…"), which is consistent with a development-stage filing.
• Current status: Philips' US holding entity has been reorganized/renamed over the decades (U.S. Philips Corporation → later Philips Electronics North America naming). No change-of-name assignment is recorded against this patent, because none was ever needed — see below. The patent itself has been dead since 1995.

Assignment timeline

Exactly one assignment is recorded. There are no post-issuance transfers, no name-change recordings, no security interests, and no releases.

• 1989-03-11 to 1989-08-30 (executed) / recorded 1989-11-20 — Reel 005182/0977
  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Christopher J. Collier and Robert J. Murray (individuals)
  • Assignee: U.S. Philips Corporation, New York
  • Correspondent: Not reproduced in the retrievable record. The Google Patents legal-events entry exposes the assignee party address ("U. S. PHILIPS CORPORATION, NEW YORK") and the reel/frame but not the correspondent attorney/firm field. I could not retrieve a correspondent name from Assignment Center directly, and I will not guess one. The reel/frame, conveyance, parties and dates above are the verified content; the correspondent field should be pulled from the Assignment Center record for reel 005182/0977 at assignmentcenter.uspto.gov. Because the chain contains only one link, the "repeat correspondent" tell cannot be evaluated at all — there is nothing to recur.
  • Context: Ordinary employer take-up of inventor rights by the corporate assignee — an internal/inbound assignment, not a sale, securitization, or transfer to an asserter.

Post-issuance legal events (no assignments among them):

Google Patents also shows an "anticipated expiration" of 2009-07-12 (filing + 20 years). That is a calculated field, not the actual term end. The patent actually died on 1995-12-20, roughly 4 years after issuance. RPX Insight independently lists the status as "Expired due to Fees."

Timeline diagram

timeline
    title Ownership of US 5073899
    1988 : Priority filing in UK by Philips
    1989 : Inventors assign rights to US Philips
         : US application filed
    1991 : Patent issued
    1995 : Patent lapses for unpaid maintenance fee

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only recorded conveyance (reel 005182/0977, recorded 1989-11-20) runs from individual inventors to an operating company. There is no transfer to any "IP / Patents / Licensing / Holdings / Ventures" entity, because there is no second assignment at all.
2. Known asserter in the chain — not present. The sole assignee is U.S. Philips Corporation, a large operating company; it does not appear on any NPE list (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities, or Unified/RPX high-frequency-plaintiff directories). Caution on a false positive: this patent appears in the citation tables of Digimarc and Wi-LAN/Uni-LAN documents (e.g. US 5,862,260, US 5,497,424 and the WO 98/32253 search report cites it as category X). Being cited by an NPE's patents is prior-art citation traffic, not an ownership link, and must not be read as chain evidence.
3. Repeat correspondent across the chain — not present (not evaluable). With a single assignment terminating in 1989, there is no second link and therefore no recurrence to detect. The correspondent of record for reel 005182/0977 was not retrievable (see timeline note).
4. Cascading transfers — not present. One assignment in the entire history, in 1989. No chained LLCs, no shared correspondent addresses, no common principals — nothing to cascade.
5. Pre-litigation transfer — not present. No infringement suit naming this patent was found. In any event the patent expired 1995-12-20, and no assignment occurs within any litigation-relevant window.
6. Bankruptcy fire-sale — not present. Philips was not in bankruptcy in this period (the 1995 lapse was a routine fee non-payment on a patent Philips evidently decided not to maintain, not a distressed asset sale). No Chapter 7/11 proceeds sale touches this patent.
7. Privateering — not present. No transfer to any third-party assertion vehicle, and no SEC disclosure or Patent Progress / EFF coverage was found connecting this patent to an on-behalf-of assertion program.
8. Defensive aggregator — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents or OIN. It terminates at Philips, then at the U.S. Patent and Trademark Office via lapse.

Verdict

Insufficient data — in substance, only the original assignment exists, and the patent was abandoned long before any assertion market could form.

Justification: the entire recorded chain is a single inventor-to-employer assignment executed 1989-03-11/1989-08-30 and recorded 1989-11-20 at reel 005182/0977, running to U.S. Philips Corporation. There is no post-issuance transfer of any kind, and the patent lapsed for non-payment of the 3.5-year maintenance fee effective 1995-12-20 (lapse noticed 1995-12-17; RPX lists status as "Expired due to Fees"), which forecloses an NPE or defensive-aggregator chain by construction — there was no enforceable right left to transfer. All eight NPE signals are "not present," and zero strong signals are present, so no NPE verdict is supportable.

For verification: USPTO Assignment Center search — assignmentcenter.uspto.gov / assignment.uspto.gov/patent/index.html (search patent number 5073899; the single hit should be reel 005182/0977, recorded 1989-11-20). Corroborating status page: insight.rpxcorp.com/patent/US5073899A.

I'll research the prior-art references cited on the face of US 5,073,899. Let me gather details on each.

Let me research the remaining cited references.

Prior Art Analysis — US 5,073,899

Patent under analysis: US 5,073,899 A — "Transmission system for sending two signals simultaneously on the same communications channel"

• Inventors: Christopher J. Collier; Robert J. Murray
• Assignee: U.S. Philips Corporation
• Appl. No. 07/378,886; filed 1989-07-12; granted 1991-12-17
• Priority: 1988-07-13 (GB 8816635)

Critical date for §102 analysis: 1988-07-13 (foreign priority) / 1989-07-12 (US filing). References granted or published before 1988-07-13 are statutory bars under pre-AIA §102(b). Post-1988 references are analyzed under §102(a)/(e), keyed to their filing dates.

Important interpretive note: I confirm the patent identity directly from the record you supplied (Google Patents rendering of the USPTO file). I did not substitute any similar-looking number (e.g., the Philips '399 LED patent family, or the "5073899" registry/investment IDs flagged in the earlier litigation section) — those are different records and are excluded here.

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1. Claim framework — what the prior art must meet

The §102-relevant independent claims are:

Dependent claims 2–3 (lower amplitude / ~20 dB), 4 (100 b/s), 5–6 (pages of text; orthogonal codes), 7 (encryption by changing the code), 8–9 (speech; FM), 10 (frequency hopping), 13–14 (sync derivation; stored orthogonal codes), 16–17 (sync output; FM) refine these.

Key observation: The "not a spread spectrum signal" and "includes a synchronization signal for the pseudo-random code and other information" language in claims 1 and 15 reads like prosecution-driven narrowing. That is precisely the language most of the cited art fails to meet, which is why the references below are mostly relevant rather than cleanly anticipatory.

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2. The 14 cited references — overview

Citations as they appear on the face of US 5,073,899 (order preserved). "§102 posture" reflects only the date rule, not substantive anticipation.

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3. Detailed reference-by-reference assessment

★ Reference 1 — US 3,666,889 A (Philips Corp) — most relevant cited reference

• Full citation: U.S. Patent 3,666,889, "Transmission system," assignee Philips Corp., filed 1966-08-27, granted 1972-05-30.
• Disclosure: A main information signal (speech, band ≈0–3,400 Hz) is combined in a linear combination device with an auxiliary signal formed by a periodic pulse pattern that is non-correlated with the main signal and lies within the main signal's frequency band, combined "without frequency separation and without time separation." The auxiliary signal (address/synchronization) has an amplitude substantially less than the information signals. At the receiver, the received combination is multiplied against a locally generated replica pulse pattern; a smoothing/integrating filter recovers the pattern for phase synchronization, and the main signal is recovered. The patent explicitly claims reducing the auxiliary signal to "50 to 60 dB below the level of the speech signal."
• §102 mapping:
  • Claim 1: Partially — discloses a lower-level auxiliary (sync-bearing) signal contained within the bandwidth of the main signal and recovered at the receiver, with the auxiliary signal itself carrying synchronization/address information. However, the auxiliary signal is a periodic pulse pattern, not produced by multiplying a first signal with a pseudo-random code to generate a spread spectrum signal. Anticipation of claim 1 is therefore not clean — but this is the single closest structural analogue to the "second signal embedded inside the first signal's band" concept.
  • Claims 2 and 3: Strongly relevant — the reference expressly teaches the auxiliary/second signal at substantially lower amplitude than the main signal (the "~20 dB lower" limitation of claim 3 is an order-of-magnitude refinement of this).
  • Claims 8, 11, 12, 13, 16, 17: Relevant on "speech," receiver-side demodulation/multiplication with a locally generated pattern, and synchronization derived from the received signal.
• Note: Same assignee as the patent under analysis (Philips), and cited as prior art against the whole EP/GB family (EP 0 351 008). In practice this is the reference an examiner or litigant would most likely lead with.

★ Reference 5 — US 4,313,197 A (Bell Telephone Laboratories; Maxemchuk)

• Full citation: U.S. Patent 4,313,197, "Spread spectrum arrangement for (de)multiplexing speech signals and nonspeech signals," assignee Bell Telephone Laboratories, Inc., filed 1980-04-09, granted 1982-01-26.
• Disclosure: A spread-spectrum signal processor that multiplexes a speech signal and a nonspeech (data) signal over a common path. At the transmitter, a block of speech is transformed to the frequency domain; a Fourier component is pseudo-randomly selected (via a PN generator) and its amplitude is incremented/decremented to carry a logic-1/logic-0 data bit — i.e., the data is spread within the speech band. The receiver synchronizes its PN generator with the transmitter's ("pseudo-random generator 230 may be synchronized with pseudo-random generator 130") and extracts both the speech and nonspeech signals.
• §102 mapping:
  • Claim 1: Potentially anticipates the core idea of spread-spectrum multiplexing of speech and data on the same path with pseudo-random selection and recovery. Arguable anticipation, with the caveats that (i) the reference frames the data as the embedded/spread signal and the speech as the carrier, whereas claim 1 does not require which of the two is spread; and (ii) it does not recite a separate "modulated second signal that is not a spread spectrum signal" bearing a synchronization signal for the PN code.
  • Claim 11: Relevant — receiver-side PN synchronization and extraction.
  • Claim 12: Relevant — despreading and narrowband extraction.
  • Claim 15: Relevant — transmitter with PN-driven spectrum manipulation, but the "modulated non-spread second signal" element is not literally met.
• Note: The reference also surveys the older art of "treat[ing] a speech signal as a carrier signal and modulat[ing] the speech signal with data signals," which is close in spirit to claim 1's "modulated second signal."

★ Reference 12 — US 4,703,474 A (AT&T Bell Laboratories; Foschini & Vannucci)

• Full citation: U.S. Patent 4,703,474, "Spread spectrum code-division-multiple-access (SS-CDMA) lightwave communication system," assignee American Telephone and Telegraph Co., AT&T Bell Laboratories, filed 1986-02-28, granted 1987-10-27.
• Disclosure: SS-CDMA combined with WDM over an optical waveguide. A PN sequence generator spreads a modulated carrier; a receiver de-spreads with a synchronized PN code and a "narrowband receiving means … for detecting a narrowband signal embedded within the other lightwave signals, and locking onto the detected narrowband signal." Expressly recites an alternative frequency-hopping (FH) code generator as a spreading mechanism.
• §102 mapping:
  • Claim 11: Relevant — despreading with the same/synchronized PN code followed by narrowband (> filter) detection of the embedded narrowband signal.
  • Claim 12: Relevant — receiver architecture (de-spreading means + narrowband receiver).
  • Claim 10 (frequency hopping): Relevant — expressly describes FH as an alternative spreading technique.
  • Claim 1/15: Weak — the "system" is optical/lightwave and CDMA-multiuser; it does not describe combining a discrete modulated (non-spread) voice signal lying within the spread spectrum bandwidth on a single radio channel.

★ Reference 3 — CA 1,046,669 A (Gunnar R. Stette)

• Full citation: Canadian Patent 1,046,669, "Spread spectrum communication techniques for a code division message multiplexing system," inventor Gunnar R. Stette, filed 1974-03-22, granted 1979-01-16 (Canadian Ministry of National Defence).
• Disclosure: SSMA/CDMA in which each message-modulated carrier receives additional modulation by a wideband pseudo-random-noise waveform (CDMA), producing a distinct waveform per carrier; the receiver selects the desired carrier by demodulation with the appropriate pseudo-random waveform. An identifiable signal / code generator is used, synchronized between transmitter and receiver, with sub-codes per channel. Also expressly notes alternative spreading by frequency hopping, phase modulation, and time hopping.
• §102 mapping:
  • Claims 1, 11, 15: Relevant — spreading a (message-modulated) carrier by a PR code and despreading at the receiver with the matching code, with synchronization derived from an identifiable signal (relevant to claim 13's "synchronizing signal" derived from the modulated signal).
  • Claims 5, 6 (multiple pages / orthogonal codes), 10 (frequency hopping), 14 (stored codes / code identifier): Relevant via its discussion of multiple code-divided channels, sub-codes, and the listed alternative spreading techniques.
  • Weakness: It does not teach a discrete voice signal lying within the spread bandwidth of a low-rate data signal as the "second signal."

★ Reference 7 — US 4,672,605 A (Applied Spectrum Technologies)

• Full citation: U.S. Patent 4,672,605, "Data and voice communications system," assignee Applied Spectrum Technologies, Inc., inventors Hustig, Ward, Moses, Bradford; filed 1984-03-20, granted 1987-06-09.
• Disclosure: Simultaneous analog voice (0–3 kHz) and data on the same twisted-pair. The data is spread/whitened with a pseudo-random code (modulo-2), with a header/sync word for synchronization, error-correction coding, and receiver-side PN despreading ("the pseudo random code will be identical to that used in the receiver"). Crucially, the data is time-compressed and transmitted in the 30–120 kHz band, above the 0–3 kHz voice band.
• §102 mapping:
  • The 5,073,899 specification expressly cites this patent and distinguishes it: it is the "one plus one technique" whose data band (30–120 kHz) is frequency-separated from the voice band, and thus "unsuitable for use on narrow band channels of say 25 KHz." Because the second signal in '605 does not lie within the bandwidth occupied by the spread spectrum signal, it does not anticipate claim 1.
  • Claims 11, 12: Relevant on receiver-side PN despreading, synchronization header, and clock recovery — but again in a frequency-separated context.
  • Claim 7 (encryption by changing the PR code): Relevant — '605 discloses a variable/selectable PR code ("any one of two hundred fifty-five sequences") for privacy.

Reference 11 — US 4,724,435 A (Applied Spectrum Technologies)

• Full citation: U.S. Patent 4,724,435, "Bi-directional data telemetry system," assignee Applied Spectrum Technologies, Inc., filed 1985-11-06, granted 1988-02-09.
• Assessment (title/assignee/date based; I did not independently retrieve the full text within this session): A spread-spectrum data telemetry system from the same assignee as '605; relevant to claims 11 and 12 (receiver-side despreading) and to the general data-over-shared-medium context. Not directed at a modulated voice signal embedded within the data's spread bandwidth. Flagged as not fully verified.

Reference 6 — US 4,835,517 A (University of British Columbia)

• Full citation: U.S. Patent 4,835,517, "Modem for pseudo noise communication on A.C. lines," assignee The University of British Columbia, filed 1984-01-26, granted 1989-05-30.
• Assessment (title/assignee based; not fully verified): A pseudo-noise modem for A.C. power-line communication. Qualifies only as §102(e) art (granted after the critical date; filed before it). Relevant to the general pseudo-noise/spread-spectrum transmission and despreading concepts (claims 1, 11, 12), but the power-line medium and the absence of a modulated co-channel voice signal limit its anticipatory value. Flagged as not fully verified.

Reference 9 — US 4,761,796 A (ITT Defense Communications)

• Full citation: U.S. Patent 4,761,796, "High frequency spread spectrum communication system terminal," assignee ITT Defense Communications, filed 1985-01-24, granted 1988-08-02.
• Assessment (title/assignee based; not fully verified): An HF spread-spectrum terminal. §102(e) art. Generally relevant to spread-spectrum transmit/receive architecture (claims 1, 11, 12, 15); not directed at embedding a non-spread modulated voice signal within the spread bandwidth. Flagged as not fully verified.

Reference 10 — US 4,866,732 A (Mitel Telecom Limited)

• Full citation: U.S. Patent 4,866,732, "Wireless telephone system," assignee Mitel Telecom Limited, filed 1985-02-04, granted 1989-09-12.
• Assessment (title/assignee based; not fully verified): A wireless telephone system. §102(e) art. Its relevance is primarily contextual — the 5,073,899 field is mobile/cordless radio where voice and data share a 25 kHz channel. It likely does not disclose the spread-plus-within-band-modulated combination. Flagged as not fully verified.

Reference 4 — US 4,071,692 A (International Standard Electric Corp.)

• Full citation: U.S. Patent 4,071,692, "Data transmission systems," assignee International Standard Electric Corporation, filed 1975-10-23, granted 1978-01-31.
• Assessment: A §102(b) reference in the data-transmission arts. I was unable to retrieve the full text within this session's search budget, so I will not characterize its disclosure beyond its title/assignee. If it discloses pseudo-random scrambling of data over a telephone/voice path, it would be relevant to claims 1, 11, 12, 15 in the same manner as the other data-over-voice art. Flagged as not fully verified — do not rely on this entry without retrieving the document.

Reference 8 — JP S61-3542 A (Sony Corp)

• Full citation: Japanese Unexamined Patent Application JP S61-3542 A, "Transmitter/receiver," Sony Corp., filed 1984-06-15, published 1986-01-09.
• Assessment: A §102(b)-eligible Japanese publication (published 1986-01-09, more than one year before the critical date), assuming an accessible translation/abstract. Full text not retrieved in this session; based on the bare title ("Transmitter/receiver") it is a generic transceiver disclosure. Flagged as not fully verified.

References 13 and 14 — US 4,941,150 A and US 4,943,976 A (Victor Company of Japan, Ltd.)

• Full citations:
  • US 4,941,150 A, "Spread spectrum communication system," Victor Company of Japan, Ltd., filed 1987-05-06, granted 1990-07-10.
  • US 4,943,976 A, "Spread spectrum communication system," Victor Company of Japan, Ltd., filed 1988-09-16, granted 1990-07-24.
• Assessment: Both are post-critical-date grants, so they are prior art only as §102(e) references (US patents granted on applications filed before the applicant's date of invention/filing). '150 (filed 1987-05-06) qualifies on its filing date. '976 is the one to watch: it was filed 1988-09-16, i.e., after the GB priority date (1988-07-13) but before the US filing date (1989-07-12). Its status as §102(e) art therefore depends on the applicant's date of invention (and on the pre-AIA Hilmer/priority analysis). Relevant generally to spread-spectrum transmit/receive (claims 1, 11, 12, 15). Full texts not retrieved; assessments are title-based only. Flagged as not fully verified.

Reference 2 — US 3,912,722 A (Shionogi & Co.) — anomaly

• Full citation: U.S. Patent 3,912,722, "Novel 6β-amino-steroids and production thereof," assignee Shionogi & Co., filed 1972-12-06, granted 1975-10-14.
• Assessment: This is a pharmaceutical/steroid chemistry patent. It is not analogous art to any claim of US 5,073,899 and cannot anticipate any claim (it lacks every claimed element — no signals, no PN code, no modulator, no spread spectrum). Its appearance in the citation list is almost certainly a citation-listing artifact. No §102 relevance.

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4. Ranking: the most relevant prior art

1. US 3,666,889 A (Philips) — closest to the core concept: an auxiliary/pilot signal carrying sync/address information, contained within the bandwidth of the main voice signal, at substantially lower amplitude, recovered at the receiver by multiplication with a locally generated replica. Lead reference for claims 1, 2, 3, 8, 11–13, 16, 17 — but fails the "pseudo-random code → spread spectrum" element of claims 1/15.
2. US 4,313,197 A (Bell Labs) — the strongest true spread-spectrum speech + data co-channel reference; potentially anticipates the spread-multiplexing concept of claims 1 and 11, but does not literally recite a non-spread modulated second signal carrying a PN synchronization signal.
3. CA 1,046,669 A (Stette) — SS/CDMA with an identifiable synchronization signal driving the code generator; relevant to claims 1, 11, 13, 14, 15, 16 and to claim 10 (alternative spreading).
4. US 4,672,605 A (Applied Spectrum) — simultaneous voice/data with PN whitening and a sync header; expressly distinguished by the patent under analysis because it is frequency-separated (30–120 kHz vs. 0–3 kHz), so it does not anticipate claim 1, but it is relevant to claims 11, 12 and to claim 7 (variable PR code for privacy).
5. US 4,703,474 A (AT&T) — despread-then-narrowband-detect architecture and FH alternative; relevant to claims 11, 12, 10.

The remaining references (US 4,071,692; US 4,835,517; JP S61-3542; US 4,761,796; US 4,866,732; US 4,724,435; US 4,941,150; US 4,943,976) are secondary/general-background spread-spectrum or transmission-system art and, on the information available to me, are not anticipatory of the independent claims.

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5. Caveats (please read)

1. "Potentially anticipates" ≠ "anticipates." On the record supplied, no single cited reference appears to disclose every element of claim 1 or claim 15 as issued — in particular the combination of (i) a pseudo-random-code spread first signal, (ii) a modulated second signal that is not a spread spectrum signal, and (iii) that second signal including a synchronization signal for the pseudo-random code and other information, with (iv) the second signal within the spread spectrum bandwidth. That is consistent with the narrow, post-prosecution wording of claims 1 and 15.
2. Unverified references. For US 4,071,692; US 4,835,517; JP S61-3542; US 4,761,796; US 4,866,732; US 4,724,435; US 4,941,150; and US 4,943,976, I was unable to retrieve and read the full specifications within this session (I exhausted my search-step budget). My descriptions are drawn from the title/assignee/date data on the face of US 5,073,899 and general knowledge; where I say "not fully verified," do not treat the anticipatory mapping as established. These should be re-checked against the actual documents (and, for the JP reference, an English abstract/translation).
3. Date nuances to preserve: US 4,866,732, US 4,835,517, US 4,761,796, US 4,941,150 and US 4,943,976 were granted after the critical date and can only be §102(e) art. US 4,943,976 (filed 1988-09-16) in particular is only prior art if the applicant's date of invention precedes that filing — worth flagging in any invalidity chart.
4. Cross-reference: This section builds on the earlier litigation summary and does not contradict it. Nothing in the prior-art record changes the finding there that the patent lapsed for non-payment of maintenance fees effective 1995-12-20 and shows no known litigation.
5. Source basis: The 14 citations and all bibliographic data are taken from the USPTO record as rendered on Google Patents for US 5,073,899 (https://patents.google.com/patent/US5073899/en). Supplemental descriptions of US 4,313,197, US 4,672,605, US 4,703,474, CA 1,046,669 and US 3,666,889 were drawn from their Google Patents / patent-image records during this analysis.

I'll ground this obviousness analysis in the actual prior-art references of record. Let me pull key details on the most material ones.

Let me pull details on the remaining references of record that bear on the two-signals-in-one-band question.

Obviousness Analysis — US 5,073,899 under 35 U.S.C. § 103

Analyst assessment. This is a technical/non-legal §103 analysis built from the prior art appearing in the Prior Art section of the authoritative record. It is not a freedom-to-operate or validity opinion, and I have not reviewed the file wrapper/prosecution history or the full text of every reference.

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1. Framework and threshold determinations

1.1 Critical date

The '899 patent's earliest effective date is the GB priority date, 1988-07-13 (GB 8816635A; US filed 1989-07-12). Prior art must therefore predate 1988-07-13 to be available. This matters, because the reference list on the face of the patent is not coextensive with §103 art.

1.2 Availability screening of the references of record

Two literal-interpretation flags:

1. US 4,941,976. On the face of the record this Victor Company patent carries a 1988-09-16 priority date — after the '899 priority date. It was nonetheless cited on the '899 as an examiner reference. If the dates are as shown, it is not §102(e)/§103 prior art against the '899 absent an earlier (e.g., JP) effective date not captured in the record I retrieved. I therefore exclude it from the combinations below and note that its citation may have been a date or arithmetic error, or the retrieved priority date may be incomplete. This is worth verifying against the JP counterpart (JPS 63-275233, 1987-05-06, appears in the same family) before relying on it either way.
2. US 3,912,722 (Shionogi, steroids) appears to be citation noise in the record — it has no discernible bearing on spread-spectrum transmission. I do not build on it.
3. OCR artifacts in the full text ("300 Hz to 3.3 Hz" for ~3.3 kHz; "25 kz" for 25 kHz) do not affect this analysis.

1.3 Level of ordinary skill (PHOSITA)

A communications/RF engineer with ~2–4 years of experience in land-mobile FM radio and in direct-sequence spread-spectrum design, familiar with the standard text (Dixon, cited by the patent itself) — including PN generation, despreading, processing gain, and code-acquisition by preamble or sliding correlator. This POSITA is presumed to know the art's conventional wisdom and common design tradeoffs, per KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007).

1.4 The claim limitations that actually carry weight

Drawn from the previously generated claim overview (not repeated) and the claim text:

• (A) the modulated second signal "is not a spread spectrum signal";
• (B) the modulated second signal "includes a synchronization signal for the pseudo-random code and other information";
• (C) the modulated signal "lies within the bandwidth occupied by the spread spectrum signal" — i.e., overlaid/co-channel, not frequency-division; and
• (D) transmission on a single channel.

The remainder (multiply by a PR code to spread; produce a modulated signal; combine; transmit; receiver demodulates + despreads the same IF in parallel; narrowband filter) is, as shown below, largely the standard DS-SS transmit/receive chain.

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2. The art of record, as it bears on each limitation

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3. Primary combination — claim 1

US 4,672,605 + US 4,313,197, optionally with Dixon.

What the combination supplies. '605 supplies the objective and the basic combination step: send voice and spread-spectrum data simultaneously over a single channel, using a pseudo-random code to spread the data. '313,197 supplies the one thing '899 does differently from '605: instead of separating the two signals into disjoint sub-bands (voice 0–3 kHz, data 30–120 kHz), overlay the data on the speech within the same bandwidth, and recover both at the receiver by despreading. '313,197 says exactly this and disparages the alternative:

"One arrangement for multiplexing speech signals and nonspeech signals uses a portion of the frequency spectrum of the path for speech signals with the remainder for nonspeech signals." … "Unfortunately, users of known arrangements … experience excessive distortion…"

That is a teaching away from the band-splitting of '605 and a pointer toward the claimed "within the bandwidth" arrangement (limitation C).

The motivation to combine (as a POSITA in 1988 would articulate it):

1. '605's own frame of reference is a wideband (120 kHz) medium (a cable pair). The '899 patent's stated problem is the narrowband 25 kHz land-mobile FM channel, where there is not enough room for a separate high-band data sub-band plus guard band. A POSITA seeking to carry the '605 idea into a 25 kHz channel would be led directly to a co-channel overlay solution, because the alternative (frequency division) is foreclosed by the bandwidth budget and expressly criticized in '313,197.
2. The overlaying approach carries a known and advertised benefit in this exact art: the data "appears as noise"/"uncorrelated noise" to a receiver not equipped with the code ('313,197; '866,732's "merely an increase in the background noise level"). This is a predictable result of spreading, not an unexpected one, and it matches the '899 spec's own description.
3. Both references are in the same field of endeavour (§103(a) analogue of KSR's "familiar elements according to known methods"), address the same problem (spectrum-efficient simultaneous voice + data), and no reference teaches away from the combination.
4. Spread spectrum itself is conceded to be known per se. The '899 specification admits: "Spread spectrum signalling techniques are known per se." The patent's own asserted point of novelty ("as far as is known the simultaneous transmission of two signals … has not been suggested before") is a statement of the inventor's belief, not evidence of unobviousness — particularly where '605 does suggest simultaneous transmission of two signals, the only difference being their spectral layout.

On the negative limitation (A). "Not a spread spectrum signal" is definitional: it separates the modulated second signal from the spread first signal. It excludes nothing beyond what the phrase "modulated second signal" already contrasts with, and it produces no asserted unexpected result. Under In re Baird / In re Grasselli reasoning, such a negative recitation adds no patentable weight where the excluded alternative was never the claimed subject matter to begin with.

On the sync limitation (B). '313,197 discloses synchronizing the receiver's PN generator to the transmitter's — "[t]he synchronization may occur by timing signals being exchanged between pseudo-random generators 130 and 230." It does not do so within the modulated speech signal. But the '899 specification itself concedes the alternatives: where no sync signal is transmitted, "synchronisation at the receiver can be performed by for example a synchronous preamble or sliding correlator disclosed … in Spread Spectrum Systems … by Robert C. Dixon." A POSITA armed with Dixon's sync techniques, plus a channel in which the entire band is occupied by the spread data, would obviously locate the low-rate code-synchronisation/control information in the only remaining in-band carrier — the FM voice signal — as opposed to dedicating a separate channel (which '899 itself treats as the wasteful alternative). FM subcarrier/ancillary-channel practice for exactly this purpose was routine in land-mobile FM (the '899 field), and Mitel's supervisory channel shows the analogous voice+data+signalling bundling.

Conclusion on claim 1: obvious over '605 + '313,197 (+ Dixon). A prima facie §103 rejection appears sustainable.

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4. Alternative combination — the DS-SS machinery route

US 4,672,605 + US 4,941,150 (+ US 4,866,732).

• '605 supplies the voice + spread data on one channel combination.
• '4,941,150 supplies the complete DS-SS transmit apparatus: modulation by a primary modulator, multiplication by a PN code, transmission; and the receiver inverse. It also supplies PN synchronization via clock/preamble extraction, and — importantly for claim 13 — extraction of the clock/sync from the received signal itself and application to the PN generator ("the clock signal is extracted from the received signal by a clock signal extracting circuit 16, and the extracted clock signal is supplied to the PN signal generator 17b").
• '4,866,732 supplies the motivation to move this into a wireless/mobile setting and to bundle voice + data + signalling.

Here, too, the only delta over '605 is the spectral overlay (limitation C), supplied by '313,197 (or by the '899 spec's own recognition that spreading inherently distributes the data across the whole channel).

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5. Claim-by-claim obviousness table

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6. Secondary considerations / objective indicia

Adopting the previously generated record (no litigation found; lapse for non-payment of maintenance fees effective 1995-12-20): no objective indicia of nonobviousness is available. There is:

• no evidence of commercial success, licensing, copying, or long-felt need with a nexus to the claimed subject matter;
• no litigation or IPR history in which the patent was defended; and
• no assertion in the specification of unexpected results. To the contrary, the spec frames its numerical choices (20 dB, 100 b/s, 25 kHz) as design preferences and tradeoffs ("considered desirable"; "in the event of having FM and spread spectrum signals of equal powers, then at the receiver one would recover a good data signal but a degraded speech signal").

These admissions cut against nonobviousness: they characterize the operative parameters as optimization among known tradeoffs — the KSR-disapproved "obvious to try" pattern, and classic In re Aller/result-effective-variable optimization.

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7. Where a nonobviousness argument could still be pressed

To be balanced, the strongest (though in my view insufficient) rebuttals are:

1. The in-band synchroniser (limitation B). Neither '313,197 nor '4,941,150 puts the code-synchronising signal inside the modulated signal. '313,197 uses a separate timing path; '4,941,150 extracts a clock from the received spread signal itself. Patentee could argue the claimed placement — hiding the code sync inside the FM voice content — is a specific architectural choice with a specific benefit (no separate sync channel in a 25 kHz channel).
   Counter: Dixon (a reference the patent itself incorporates) plus the '899 spec's own statement of alternatives, plus ordinary FM ancillary-channel practice, make the placement an obvious design choice. Mitel's supervisory channel is close.
2. The overlap (limitation C). '605 arguably teaches away from overlay by segregating data above the voice band. Patentee could argue the art pointed to frequency separation, not co-channel overlay.
   Counter: '313,197 is the express contrary teaching, and the '899 spec's own problem statement (25 kHz bandwidth) supplies the reason to abandon '605's band-split. A single reference teaching away is not enough where another reference in the same field teaches toward the claimed arrangement.
3. The negative limitation (A). Weakest of all; likely entitled to no weight.

None of these, individually or together, appears to me to overcome the combination, particularly given the specification's self-admissions and the total absence of objective indicia.

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8. Bottom line

Confidence and limitations, stated explicitly: (i) I did not retrieve the full text or claims of US 3,666,889 (Philips, "Transmission system," 1966), US 4,071,692, JPS 61-3542 A, or US 4,835,517; my characterizations of those are limited to their titles/dates and I have not relied on them for any rejection. That omission does not weaken the combinations above, which rest on references I did retrieve. (ii) The US 4,941,976 date anomaly is flagged, not resolved. (iii) I did not review the actual prosecution history, so my inference about the examiner's reasoning is an inference. (iv) All dates are taken literally from the authoritative Google Patents record as fetched; no patent numbers or identifiers have been auto-corrected. (v) Where the record contradicts itself on the '899's statutory status, the previously generated sections' literal reporting is adopted unchanged.

I'll run targeted searches against USPTO-facing sources for this specific patent number.

Let me check for continuation/divisional children claiming benefit of application 07/378,886, and confirm the PTA/PTE position.

US 5,073,899 — Term Adjustments, Continuity, Family, and Expiration

Scope note / limitation up front. I could not reach USPTO PatentCenter or the Patent Assignment/PAIR continuity screens directly in this session — those interfaces are JavaScript-driven and my USTPO-facing queries returned only the static document repositories (uspto.report, EPO's DOCDB/PISE records, Google Patents, FreePatentsOnline). The analysis below is reconstructed from (a) the authoritative full record you supplied, (b) the EPO DOCDB family record returned in this session, and (c) the USPTO rules text returned in this session. Where a field is not exposed by those sources, I say so rather than fill it in.

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1. Identification (literal)

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2. Patent Term Adjustment (PTA) — NONE. Not available as a matter of law.

Result: no PTA was granted, and none could have been. This is not a judgment call — it is a statutory-eligibility bar:

• PTA (35 U.S.C. § 154(b), as implemented by 37 CFR 1.702–1.705) applies only to applications filed on or after 29 May 2000. The USPTO's own petition decision returned in this session states the rule verbatim: *"For applications filed on or after 29 May 2000, patent term adjustment is available if the issuance of the patent was delayed due to the failure of the Office to perform certain acts in a timely manner. See 37 CFR 1.702. Because the instant application was filed prior to 29 May 2000, the application is not eligible for patent term adjustment under 37 CFR 1.702."*
• US 07/378,886 was filed 1989-07-12 and issued 1991-12-17 — roughly nine years before the AIPA PTA regime existed and nearly four years before the URAA (enacted 1994-12-08) even created the 20-year term.
• Corroborating negative evidence on the face of the document: the granted patent as reproduced in the authoritative record carries no PTA notice line (compare modern grants, which carry "(*) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by N days"). There is no such line for US 5,073,899, and no PTA figure appears anywhere in its bibliographic data.

Bottom line: PTA = 0 days. Not applicable.

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3. Patent Term Extension (PTE) — NONE. Not applicable on the technology.

PTE under 35 U.S.C. § 156 (the Hatch-Waxman / patent term restoration provision) is available only for patents that claim a product, a method of using a product, or a method of manufacturing a product where the product is subject to a regulatory review period before commercial marketing — i.e., a drug, medical device, food additive, or color additive under the FDCA (or a veterinary biological under the Virus-Serum-Toxin Act).

US 5,073,899 claims a spread-spectrum data + FM voice transmission system (claims 1, 11, 12, 15). It is not within any § 156-eligible product category. The patent would therefore not appear in the ODP/PTE Register, and — consistently — no "(*) Term of this patent extended to…" notice appears on the patent's face in the authoritative record.

Bottom line: PTE = none. The patent is ineligible by subject matter.

(A related but distinct mechanism — the pre-URAA § 154(c)(1) transition rule giving the greater of 20-years-from-filing or 17-years-from-grant — is addressed in § 6 below, because it affects the projected expiration.)

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4. Continuation / Divisional Applications — NONE found in the US chain

• The record lists exactly one US application in this family: US 07/378,886. Google Patents' "Family Applications (1)" table contains only that application; there is no second US application number, no "CON" or "DIV" relationship, and no child application claiming benefit under § 120 of 07/378,886.
• The prosecution-to-grant interval was ~29 months (1989-07-12 → 1991-12-17), consistent with a single-pass prosecution rather than a restriction/divisional scenario.
• Priority chain: US 07/378,886 claims foreign priority only — to GB 8816635 A (1988-07-13). There is no earlier US parent and therefore no § 120 benefit claim.
• No US continuation-in-part, continuation, or divisional was located. I did not confirm this against PatentCenter's "Continuity Data" tab directly (see scope note); that is the one remaining verification step. Google Patents' and EPO DOCDB's structured family tables independently show a single US member, which is strong but not dispositive corroboration.

Caution on a false-positive source. Search results for "US 5073899" surface the Wi-LAN/Uni-LAN and Digimarc continuation families (e.g., US 5,497,424 / US 5,862,260 / US 6,324,573) purely because US 5,073,899 appears in their "References Cited" tables (FreePatentsOnline's citation table for US 6,324,573 lists: "5073899 | Transmission system for sending two signals simultaneously on the same communications channel | 1991-12-17 | Collier et al. | 375/202"). That is prior-art citation traffic, not a continuity relationship. Do not read those families as children of US 5,073,899.

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5. Related family members (foreign counterparts)

From the EPO DOCDB simple-family record retrieved this session (application numbers preserved literally):

Designated EPC contracting states: DE, FR, GB, IT, SE (EP 0351008).
Classifications: IPC H04B 1/707; H04M 11/06; H04J 13/00 (CPC: H04B1/707, H04M11/06, H04J13/0022).

The family is fragmented and fully abandoned — no member survives. Note the internal tension flagged in the previously generated sections: the GB priority member GB 2220824 A is carried as Withdrawn, yet it is the sole priority basis for the granted US, EP, CA, JP and FI members.

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6. Projected expiration date — the answer has two layers

(a) Nominal / statutory term

Because US 07/378,886 was filed before 1995-06-08 (the URAA's six-month transition date), the pre-AIA transition rule of 35 U.S.C. § 154(c)(1) applies — the term is the greater of 20 years from filing or 17 years from grant (subject to terminal disclaimers, of which there are none here):

→ The controlling nominal term is the greater, i.e. 2009-07-12. This is the date Google Patents reports as "Anticipated expiration 2009-07-12." (No PTA and no PTE are added, for the reasons in §§ 2–3, so no adjustment to this figure is possible.)

(b) Actual expiration — 1995-12-20

The patent never reached its nominal term. From the legal-events record:

Effective expiration date: 1995-12-20 — approximately 4 years and 3 days after grant, and roughly 13.5 years before the nominal 2009-07-12 term would have run. The patent's enforcement life was 1991-12-17 → 1995-12-20.

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7. Summary table

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8. Caveats

1. PTA/PTE are definitional negatives, not search-derived gaps. They follow from the filing date (1989) and the claimed subject matter (RF/telecom), respectively, and are corroborated by the absence of any adjustment/extension notice on the patent's face in the authoritative record.
2. Continuity is the weakest-verified element. I confirmed a single US family member via Google Patents' "Family Applications (1)" table and the EPO DOCDB simple-family application list, but I did not open PatentCenter's continuity tab for 07/378,886. If absolute certainty on the absence of a US continuation/divisional is needed, run PatentCenter application 07/378,886 → "Continuity Data" and cross-check the "Child Applications" listing, and separately confirm no application anywhere claims § 120 benefit of 07/378,886.
3. The record is internally inconsistent on status (1995–96 lapse vs. 2009 anticipated expiration vs. the 2018 STCH entry). Per the rule of literal interpretation, I have reported each entry as written rather than resolving it; the two dates are answering two different questions (actual vs. nominal term), which is the most coherent reading of the record.
4. Identifier collisions. "5073899" also resolves to JP 5073899 B2 (organic EL device — the hit returned in this session's organic-EL search results) and to unrelated registry/investment IDs. None of those is US 5,073,899, and none was merged into this analysis.

Sources used in this session: uspto.report/patent/grant/5073899; EPO DOCDB/PISE family record for EP 0351008 A2 (data.epo.org); FreePatentsOnline citation table for US 6,324,573; USPTO petition-decision text quoting 37 CFR 1.702's 2000-05-29 eligibility cutoff; USPTO MPEP § 2700 materials on 37 CFR 1.704; and the authoritative Google Patents record for US 5,073,899 supplied in the prompt.