DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Response to Arguments
Applicant's arguments filed on 6 July 2026 have been fully considered but they are not persuasive. Applicant argues that the combination of Goldberg et al. ("Goldberg") and Staub et al. ("Staub") does not teach or suggest the use of a single measuring circuit to measure the sum of cathode currents M∑Ik to determine corrected anode voltages for a plurality of TWTs. Applicant further asserts that Staub is directed to over-current protection and not automatic regulation, and thus provides no motivation for the claimed invention. These arguments are not persuasive.
Applicant contends that the skilled artisan would not be motivated to combine Staub with Goldberg because Staub addresses TWT deterioration through protection rather than regulation. This is unpersuasive. Goldberg teaches the fundamental concept of an automated feedback loop utilizing a current sense circuit to adjust anode voltage for cathode current stabilization. Staub teaches the fundamental concept of shared sensing for multiple TWTs to reduce mass and volume. The modification of Goldberg’s system to utilize a shared sensing circuit—a concept explicitly motivated by the common goal in both references to increase satellite payload efficiency and reduce hardware—would be readily apparent to one of ordinary skill in the art. The implementation of feedback regulation based on a summed measurement, once the measurement architecture is established through the combination of the teachings, follows standard control theory and does not require inventive ingenuity.
Applicant’s argument regarding Staub’s focus on over-current protection misses the functional synergy taught by the combination. The core mechanism—using a single circuit to measure a shared or aggregate parameter—is exactly what is proposed. Once a POSITA establishes that a single circuit can provide the aggregate current data, using that data as a basis for the feedback control loop already taught by Goldberg (which adjusts anode voltage based on current feedback) is a straightforward implementation. The rejections under 35 U.S.C. § 103 are therefore maintained.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-2, 5-10, and 14-15 are rejected under 35 U.S.C. 103 as unpatentable over Goldberg et al., (US 7,358,803 B2) in view of Staub et al. (US 6,586,883 B1).
Claim 1, recites a satellite system comprising: (a) a control and supply module; (b) a plurality N of travelling wave tubes; (c) the module applying anode voltage operating value VaOn to at least one tube; (d) the tube generating cathode current Ik; (e) the module measuring at least one sum of cathode currents M∑Ik associated with the plurality N of TWTs, said measurement implemented on the basis of a single measuring circuit; (f) determining at least one corrected anode voltage on the basis of that sum measurement; and (g) applying the corrected anode voltage to the tube.
Element-by-element mapping against Goldberg:
Claim 1 Limitation
Goldberg Disclosure
Satellite system
Satellite communication system 14 (Figs. 1–2, Col. 3)
Radio frequency signal amplifier device
High Power Amplifier Circuits 28 with TWT amplifier systems 19 (Figs. 2–3)
Control and supply module
Electronic Power Conditioner 56 with Telemetry and Command Interface 62, programmable circuit 76, and look-up table 72; also Spacecraft Control Processor 42 (Fig. 3, Col. 4)
Plurality N of travelling wave tubes
Figure 2 explicitly shows N high power amplifier circuits 28 (1 through N), each containing a TWT amplifier system 19 with an anode-controlled TWT 90 (Figs. 2–3)
Applying anode voltage operating value VaOn
Electronic power conditioner 56 adjusts anode voltage of TWT 46/90 via current sense circuit 60 and anode control 104 (Fig. 3, Col. 4: "adjusts anode voltage…to maintain a constant cathode current")
Tube generating cathode current Ik in response to anode voltage
TWT 90 generates electron beam modulated by anode control 104; current sense circuit 60 monitors resulting cathode current (Figs. 3–4, Col. 4)
Measuring sum of cathode currents M∑Ik associated with plurality N of TWTs, implemented on the basis of a single measuring circuit
PARTIAL DISCLOSURE. Current sense circuit 60 is disclosed as monitoring cathode current of a single high power amplifier 46 per conditioner 56. Figure 2 shows each of the N amplifier circuits 28 has its own individual power conditioner 56 with its own current sense circuit 60. Goldberg does NOT disclose a single measuring circuit measuring the aggregate sum of cathode currents across all N TWTs simultaneously.
Determining corrected anode voltage on the basis of said sum measurement
Current sense circuit 60 and look-up table 72 (parameters: anode voltage, cathode current, gain, offset) in programmable circuit 76 compute adjusted anode voltages (Fig. 3, Col. 4–5). However, this is done per-tube, not based on a summed multi-tube measurement.
Applying corrected anode voltage to the tube
Anode control 104 receives corrected anode voltage from high voltage amplifier 86 (Fig. 4, Col. 5–6)
Analysis and Reason for Obviousness:
Goldberg teaches all elements of Claim 1 except the specific architecture of using a single measuring circuit to measure the sum of cathode currents from the plurality N of TWTs collectively, and then using that aggregate sum to derive individual corrected anode voltages. In Goldberg, each TWT amplifier circuit 28 has its own dedicated power conditioner 56 with its own current sense circuit 60 (Fig. 2–3).
Staub teaches in Fig. 2, a method and apparatus to individually detect the cathode to helix current of multiple TWTs sharing a common cathode to helix voltage supplied by a single High Voltage Electronic Power Converter, which provides the capability to determine which tube has exceeded the limit and to adequately protect each helix structure from destruction due to excessive current. Such a single current measurement of multiple TWT or electron tube cathode currents using a single shared sensing circuit, is particularly useful for satellite applications for the purpose of shared feedback control. It provides well-understood advantages: (1) reduced circuit complexity and component count, (2) reduced cost and mass (important for satellite payloads), (3) simplified telemetry.
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Fig. 4 of Goldberg reproduced for ease of reference.
Therefore, a person of ordinary skill in satellite TWT amplifier design would recognize that measuring the aggregate sum of N cathode currents with a single shared measuring circuit provides several Replacing N individual current sense circuits with a single shared summing current measurement circuit following the teaching of Staub represents a straightforward hardware simplification — the kind of design optimization that persons of ordinary skill in satellite power electronics routinely pursue to reduce spacecraft mass and cost. The motivation is explicitly present in Goldberg itself: Col. 2 states that reducing power consumption and spacecraft component count is a key goal, and "additional transponders may be deployed on a satellite" by reducing component overhead.
Accordingly, claim 1 is rejected under 35 U.S.C. § 103 over Goldberg in view of Staub. A person of ordinary skill would have been motivated to replace the N individual current sense circuits of Goldberg with a single summing measurement circuit, arriving at the claimed architecture with a reasonable expectation of success.
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Fig. 2 of Staub reproduced for ease of reference.
Claim 2 additionally recites that each tube is associated with a given operating point PFn having a cathode current setpoint value CIkn and an anode voltage setpoint value CVaOn; the module applies CVaOn to each tube; the module activates a correction mode during which it: (i) performs a single measurement M∑Ik of the sum of cathode currents at operating points PFn; (ii) determines, for each tube, a corrected anode voltage DVaOn based on that single sum, the setpoint CIkn, and the setpoint CVaOn; and (iii) applies DVaOn to each tube.
The resultant combination of Goldberg in view of Staub teaches:
Operating points per tube: Look-up table 72 in programmable circuit 76 (Fig. 3) stores "gain, offset, set-point, anode voltage, cathode current, and phase and their respective relationship to each other for a plurality of complementary states of associated output saturated power" (Col. 4–5). This constitutes a stored operating point PFn with anode voltage setpoint CVaOn and cathode current setpoint CIkn.
Applying setpoint CVaOn: Power conditioner 56 applies the anode voltage from LUT 72 to each TWT (Fig. 3, Col. 4).
Correction mode: Goldberg's power conditioner 56 continuously monitors cathode current via current sense circuit 60 and adjusts anode voltage via a servo loop to maintain constant cathode current at a "predetermined level" (Col. 4). While Goldberg describes this as a continuous adjustment rather than a discrete "correction mode," the concept of activating a corrective adjustment based on a cathode current measurement is directly taught.
Determining corrected anode voltage DVaOn: Current sense circuit 60 uses cathode current feedback to compute anode voltage correction; LUT 72 provides the relationship between anode voltage and cathode current for adjustment (Col. 4–5).
Claim 5 depends on Claim 2 and recites that the control and supply module, during correction mode, further determines a drift ratio Q∑IK based on the single measured sum M∑Ik and a sum of the cathode current setpoint values CIkn of the N tubes.
The drift ratio Q∑IK = M∑Ik / ∑CIkn is simply the ratio of the measured aggregate cathode current to the nominal aggregate cathode current setpoint. This represents aggregate tube performance versus specification.
Goldberg's power conditioner 56 and current sense circuit 60 inherently perform a comparison between measured cathode current and a setpoint (the "predetermined level" of Col. 4). Goldberg's LUT 72 stores cathode current setpoints and their relationship to anode voltages (Col. 4–5). The controller 42 and spacecraft control processor monitor overall system performance via telemetry output 68 (Fig. 3).
Computing a ratio of measured to expected current (a normalized drift metric) is an elementary and universally standard performance monitoring technique in power electronics and satellite systems engineering. A person of ordinary skill would immediately arrive at such a drift ratio as a diagnostic metric when implementing the summed current monitoring architecture of Claim 1 of Goldberg modified in view of Staub.
Claim 6 depends on Claim 2 and recites that application of the corrected anode voltage dVaOn is performed in response to a detection of a performance drift of at least one tube.
Goldberg explicitly discloses condition-triggered anode voltage correction. Power conditioner 56 continuously monitors cathode current via current sense circuit 60 and "adjusts anode voltage of the high-power amplifier 46 to maintain a constant cathode current at a predetermined level" (Col. 4). The adjustment is triggered when the monitored cathode current deviates from the setpoint — i.e., when performance drift is detected. Furthermore, Goldberg Col. 1 states that "over time, as a cathode of the high power amplifier degrades, the power supply compensates for this change by adjusting anode voltage" — directly describing response to cathode performance drift.
The only difference is again the summed multi-tube architecture versus individual per-tube sensing. The conditional triggering upon drift detection is expressly taught by Goldberg's current sense circuit 60 feedback mechanism.
Claim 8 depends on claim 5 and recites that the control and supply module comprise a stored data set of operating points PFn, and the performance drift is determined based on comparison of the drift ratio Q∑IK with a drift threshold in that data set.
Goldberg's LUT 72 in programmable circuit 76 stores cathode current setpoints and performance parameters (Col. 4–5). Comparing a computed ratio to a stored threshold is a completely standard control engineering technique for triggering corrective action. Goldberg's current sense circuit 60 performs threshold-based current monitoring (maintaining current "at a predetermined level" implies a threshold comparison). The concept of a drift ratio threshold (Q∑IK vs. stored threshold) follows directly from Goldberg's performance monitoring architecture and the drift ratio concept of Claim 5.
Claim 9 depends on claim 6 and recites that performance drift is determined based on a comparison of the corrected anode voltage DVaOn with the associated anode voltage setpoint CVaOn.
Goldberg explicitly discloses this comparison mechanism. The power conditioner 56 monitors cathode current and adjusts anode voltage; the deviation of the corrected anode voltage from the stored setpoint value in LUT 72 is inherently the basis for detecting performance change. Goldberg Col. 1 states: "over time, as a cathode of the high-power amplifier degrades, the power supply compensates for this change by adjusting anode voltage" — meaning the deviation of the adjusted voltage from the nominal setpoint voltage directly signals cathode degradation (performance drift). The comparison of corrected versus setpoint anode voltage as a drift indicator is inherently taught by Goldberg's anode voltage adjustment feedback mechanism.
Claim 10 depends on claim 2 and recites that the control and supply module comprise an internal clock and the correction mode is activated in response to a detection of a predefined time stamp.
Goldberg's spacecraft control processor 42 is "preferably microprocessor based such as a computer having a central processing unit, memory (RAM and/or ROM), and associated input and output buses" (Col. 3). A microprocessor-based controller inherently includes an internal clock as a fundamental hardware component. Periodic execution of correction/compensation routines triggered by a timer or time stamp is a universally standard feature of embedded control systems, including satellite power management systems. Any person of ordinary skill implementing Goldberg's cathode current monitoring system in a microprocessor-based controller (42) would automatically implement time-triggered correction cycles. Time-stamp-triggered periodic correction using an internal microprocessor clock is an inherent and routine feature of the microprocessor-based controller 42 disclosed by Goldberg.
Claim 14 depends on claim 12 and recites that the calibration mode is activated in response to detection of a performance drift.
Goldberg's power conditioner 56 and current sense circuit 60 are triggered by cathode current deviations from the setpoint (performance drift): "Over time, as a cathode of the high power amplifier degrades, the power supply compensates for this change by adjusting anode voltage" (Col. 1). Triggering a calibration procedure upon detection of such drift (rather than continuous reactive correction) is an obvious design choice within the ordinary skill of satellite TWT power system engineers. Goldberg's programmable circuit 76 and controller 42 provide the computational infrastructure to implement drift-triggered mode activation. Triggering calibration upon drift detection is a straightforward extension of Goldberg's drift-responsive current monitoring architecture.
Claim 15 is an independent method claim reciting:
Applying anode voltage VaOn to at least one of N TWTs
Measuring the sum of cathode currents M∑Ik using a single measuring circuit
Determining corrected anode voltage based on that sum measurement
Applying the corrected anode voltage
This method claim maps directly to the apparatus of Claim 1, and the same analysis applies. Goldberg teaches all method steps except the single-circuit aggregate sum measurement (steps 2–3), which is obvious for the same reasons stated for Claim 1.
Mapping against Goldberg's Figure 4 / Figure 3 process flow:
Step 1 (applying VaOn): Anode control 104 applies voltage to TWT 90 under direction of high voltage amplifier and impedance transformer 86 based on LUT 102 (Fig. 4)
Step 2 (measuring M∑Ik): Current sense circuit 60 in power conditioner 56 monitors cathode current per tube (Fig. 3); the aggregate sum from N tubes using a single circuit is the obvious simplification
Step 3 (determining corrected voltage): LUT 72 in programmable circuit 76 computes corrected anode voltage from current measurement and stored parameters (Fig. 3, Col. 4–5)
Step 4 (applying corrected voltage): Anode control 104 receives the corrected signal (Fig. 4)
Accordingly, claim 15 is rejected under 35 U.S.C. § 103 over Goldberg in view of Staub for the reasons stated for Claim 1.
Allowable Subject Matter
Claims 3-4, 7, and 11-13 are objected to as being dependent upon a rejected base claim 1 and 5 respectively but would be allowable if rewritten in independent form including all the limitations of the base claim 5 and any intervening claims.
Claim 3 specifies that the corrected anode voltage dVaOn is determined based on an estimated perveance value dGn and the cathode current setpoint CIkn, defined by the specific formula: dVaOn = (CIkn / dGn)^(2/3)
This formula derives directly from Child-Langmuir space charge limited emission theory (the "3/2 power law": Ik = G × Va^(3/2), hence Va = (Ik/G)^(2/3)), where G is the perveance of the tube. Goldberg does not disclose, teach, or suggest the concept of perveance (G or DGn) as a parameter in the anode voltage correction calculation, estimating perveance from sum measurements of cathode currents and the specific Child-Langmuir 3/2-power formula as the basis for anode voltage correction
Goldberg's current sense circuit 60 and LUT 72 operate on empirically stored look-up table relationships (Col. 4–5), not on the analytically derived perveance-based formula of Claim 3. The concept of modeling TWT cathode emission via perveance and using it in feedback control is a specialized and non-obvious application to the satellite multi-TWT context claimed.
Claim 4 specifies that the corrected anode voltage dVaOn is determined based on a derivative formula for the cathode current with respect to the anode voltage of the tube at operating point PFn. This recites a linearized differential correction approach — using the local slope ∂Ik/∂Va evaluated at the operating point PFn to compute a first-order correction to the anode voltage. Goldberg uses empirical LUT 72 for anode voltage adjustment (Col. 4–5), not a derivative-based analytical correction. There is no teaching or suggestion in Goldberg of computing ∂Ik/∂Va at an operating point and using it for voltage correction.
Claim 11 introduces predictive/prognostic capabilities — using historical time-stamped data to extrapolate future tube performance (e.g., predicting when a tube will degrade beyond acceptable limits). This is a fundamentally different concept from Goldberg's reactive feedback control.
With regards to claims 12-13, the specific two-step calibration protocol (applying two successive anode voltages to a single tube while monitoring the aggregate sum from all N tubes) is not disclosed. Goldberg calibrates from ground testing, not through in-orbit sequential voltage application with aggregate sum measurement comparison.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HAFIZUR RAHMAN whose telephone number is (571)270-0659. The examiner can normally be reached M-F: 10-6.
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/HAFIZUR RAHMAN/Primary Examiner, Art Unit 2843.
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