N77-10428* National Aeronautics and Space Administration. Pasadena Office, Calif. THE de-TO-de CONVERTERS EMPLOYING STAGGEREDPHASE POWER SWITCHES WITH TWO-LOOP CONTROL Patent Gene W. Wester, inventor (to NASA) (JPL) Issued 5 Oct. 1976 7, p Filed 17 Dec. 1974 Published under the second Trial Voluntary Protest Program as B 533 734, 27 Jan. 1976 Sponsored by NASA (NASA-Case-NPO-13512-1; US-Patent-3,984,799; US-Patent-Appl-SN-533734; US-Patent-Class-321-2; US-Patent-Class-321-19; US-Patent-Class-323-17; US-Patent-Class-323-22T; US-Patent-Class-323-23; US-Patent-Class-323-DIG. 1) Avail: US Patent Office CSCL thereby protect electric circuits within the spacecraft. Official Gazette of the U.S. Patent Office 12 21 2118 N77-11296*# National Aeronautics and Space Administration. Hugh L. Dryden Flight Research Center, Edwards, Calif. WINDOW COMPARATOR Patent Application James M. Black, inventor (to NASA) Filed 2 Nov. 1976 16 p (NASA-Case-FRC-10090-1; US-Patent-Appl-SN-737974) Avail: NTIS HC A02/MF A01 CSCL 09C A comparator comprising two operational amplifiers is described. The first has two feedback circuits, each having a diode connected to the amplifier output and poled for forward current conduction of opposite polarity, such that one diode conducts and then switches off while the other is held off and then conducts when the sign of the algebraic difference switches. Differential input terminals of the second operational amplifier are connected to the separate feedback circuits of the first operational amplifier. A selected window-width voltage is connected through a coupling resistor to one of the input terminals of the second operational amplifier to determine when the algebraic difference of the input signal and the set-point voltage has exceeded a predetermined tolerance after that difference has changed signs. Author + Vrel Vsp 15 16 N77-10429* National Aeronautics and Space Administration. Goddard Space Flight Center, Greenbelt, Md. METHOD AND APPARATUS FOR NEUTRALIZING POTENTIALS INDUCED ON SPACECRAFT SURFACES Patent Robert E. Hunter, inventor (to NASA) Issued 5 Oct. 1976 6 p Filed 11 Jul. 1975 (NASA-Case-GSC-11963-1; US-Patent-3,984,730; US-Patent-Appl-SN-595197; US-Patent-Class-317-2D; US-Patent-Class-244-1A; ÚS-Patent-Class-244-42CG; US-Patent-Class-324-72) Avail: US Patent Office CSCL 09C A potential induced on the surface of an orbiting spacecraft is neutralized to the potential of a plasma through which the spacecraft is traveling by directing charged particles into the plasma from the spacecraft surface. The induced potential occurs in response to bombardment of the spacecraft surface by ambient charged particles which may be negative or positive. The charged particles directed into the plasma from the surface have the same polarity as the induced potential to provide the neutralization. The invention can be utilized to maintain different, electrically isolated segments of a spacecraft surface at the same potential to prevent electric discharges between the different parts and Frequency discriminator and phase detector circuits are disclosed, each having two flip-flops, one flip-flop for each of two signals to be compared. Means are provided for causing one flip-flop to be set the majority of the time in proportion to the extent to which one signal differs from the other in frequency or phase. A method is also provided for integrating the difference between output waveforms of the flip-flops to obtain an output signal which can be used to adjust the frequency of phase of a variable signal with respect to a reference signal. NASA 27 A method is described for circuit protection from abnormal surge voltages induced in a shielded cable. The cable system carries one or more insulated conductors completely enclosed within a shield having one end connected to ground. A lightningprotector network connects the other end of the shield to ground. The protector network is normally open circuited and becomes short circuited only in response to a momentary abnormal surge voltage induced in the shield. The protector network's open-toshort impedance change completes a conductive circuit path between the shield and the two grounded ends for conducting a shield current which has the desired effect of protecting the signal carrying conductors in the cable from the large surge voltage. Author (NASA-Case-MSC-14916-1; US-Patent-Appl-SN-739914) Avail: NTIS HC A03/MF A01 CSCL 09C A system for detecting malfunctions in electrical signal processing circuits is presented. Malfunctions of a hearing aid are detectable in the form of frequency distortion and/or inadequate amplification by the hearing aid amplifier, as well as weakening of the hearing aid power supply. A test signal is generated and a timed switching circuit periodically applies the test signal to the input of the hearing aid amplifier in place of the input signal from the microphone. The resulting amplifier output is compared with the input test signal used as a reference signal. The hearing aid battery voltage is also periodically compared to a reference voltage. A warning is triggered if the power supply voltage falls below the reference voltage. Author (NASA-Case-GSC-11789-1; US-Patent-3,996,506; US-Patent-Appl-SN-538982; US-Patent-Class-321-13; US-Patent-Class-317-31) Avail: US Patent Office CSCL 09C A circuit arrangement for limiting turn-on current inrush and current rate of rise in dc-to-dc power converters is considered. A transistor control circuit is disposed between the input dc power source and the transistor oscillator circuit of the converter to provide a ramp of current thereto. The transistor control circuit functions as a time-variable current limiter initially while in the active region and as a saturated switch in the steady-state region. A feedback arrangement allows the saturation drive current to be provided from the converter at a lower voltage level than that which may be required from the dc power source to reduce dissipation and increase efficiency. Official Gazette of the U.S. Patent Office N77-14334* National Aeronautics and Space Administration. Goddard Space Flight Center, Greenbelt, Md. UNEAR PHASE DEMODULATOR INCLUDING A PHASE LOCKED LOOP WITH AUXILIARY FEEDBACK LOOP Patent Ronnie R. Rippy, inventor (to NASA) Issued 14 Dec. 1976 8 p Filed 26 Nov. 1975 (NASA-Case-GSC-12018-1; US-Patent-3,997,848; A phase modulated wave that may have no carrier power is demodulated by a phase locked loop including a phase detector for deriving an A.C. data output signal having a magnitude and a phase indicative of the phase of the modulated wave. A feedback loop responsive to the data output signal restores power to the carrier frequency component to the loop. In one embodiment, the feedback loop includes a phase modulator responsive to the phase modulated wave and the data output signal. In a second embodiment, carrier frequency power is restored by differentiating the data output signal and supplying the differentiated signal to an input of a voltage controlled oscillator included in the phase locked loop. Official Gazette of the U.S. Patent Office N77-17351* National Aeronautics and Space Administration. Marshall Space Flight Center, Huntsville, Ala. FREQUENCY MODULATED OSCILLATOR Patent Martial A. Honnell, inventor (to NASA) (Auburn Univ., Ala.) Issued 11 Jan. 1977 5 p Filed 9 Apr. 1975 Sponsored by NASA (NASA-Case-MFS-23181-1; US-Patent-4,003,004; US-Patent-Appl-SN-566495; US-Patent-Class-332-30V; US-Patent-Class-331-114; US-Patent-Class-331-177V; US-Patent-Class-332-18) Avail: US Patent Office CSCL 09A A frequency modulated push-pull oscillator in which the non-linear characteristic of varactors producing frequency modulation is compensated for by an opposite non-linear characteristic of a field effect transistor providing modulating bias to the varactors is described. Official Gazette of the U.S. Patent Office (NASA-Case-MFS-22560-1; US-Patent-3,996,462; US-Patent-Appl-SN-589233; US-Patent-Class-250-214A; US-Patent-Class-330-14; US-Patent-Class-330-28; US-Patent-Class-330-59) Avail: US Patent Office CSCL 09C A signal transformation network which is uniquely characterized to exhibit a very low input impedance while maintaining a linear transfer characteristic when driven from a voltage source and when quiescently biased in the low microampere current range is described. In its simplest form, it consists of a tightly coupled two transistor network in which a common emitter input stage is interconnected directly with an emitter follower stage to provide virtually 100 percent negative feedback to the base input of the common emitter stage. Bias to the network is supplied via the common tie point of the common emitter stage collector terminal and the emitter follower base stage terminal by a regulated constant current source, and the output of the N77-17354* National Aeronautics and Space Administration. Lewis Research Center, Cleveland, Ohio. ELECTRONIC ANALOG DIVIDER Patent Arthur G. Birchenough, inventor (to NASA) Issued 4 Jan. 1977 4 p Filed 24 Jul. 1975 N77-17357*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, Ohio. METHOD OF ELECTRICALLY PRE-STRESSING INSULATION TO PROVIDE DIRECTIONAL INCREASE IN dc POTENTIAL BREAKDOWN Patent Application Irving G. Hansen, inventor (to NASA) Filed 31 Jan. 1977 7 p (NASA-Case-LEW-12273-1; US-Patent-Appl-SN-764253) Avail: NTIS HC A02/MF A01 CSCL 09C A method was provided for electrically pre-stressing an insulator to increase the dc breakdown strength of the insulator in a given direction. The method comprises placing an uncured, durable insulating material, such as an epoxy resin, in an electric field and curing the insulating material while maintaining the field so as to capture an electric field within the insulating material. The electric field biasses the breakdown potential in a given direction so that the insulation is able to withstand a substantially greater dc operating voltage of the appropriate polarity. NASA (NASA-Case-NPO-13872-1; US-Patent-Appl-SN-742034) Avail: NTIS HC A02/MF A01 CSCL 09C An overload protection system for a power inverter utilizes a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter when an overload condition is detected. At the same time a monitoring current inverter is turned on to deliver current to the load at a very low power level. A second circuit monitors current to the load from the monitoring current inverter to hold the power inverter off through the control circuit until the overload condition is cleared so the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely. NASA (NASA-Case-NPO-13909-1; US-Patent-Appl-SN-744477) Avail: NTIS HC A02/MF A01 CSCL 09C A method and apparatus for recording directly group delay measurement of a system under temperature and stress tests employing a modulated carrier frequency swept over an S or X band of interest is described and applied through a reference path and a test path to separate detectors for group delay measurement using a power divider, a directional coupler or a hybrid T junction. A phase comparator is initially balanced, and then the modulated carrier is swept in frequency over the band of interest for different conditions of temperature and/or mechanical stress to obtain a family of characteristics group delay curves for the system under test. NASA LOAD N77-17360*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, Ohio. TRAVELING WAVE TUBE CIRCUIT Patent Application Denis J. Connolly, inventor (to NASA) Filed 15 Feb. 197712 p (NASA-Case-LEW-12013-1; US-Patent-Appl-SN-768795) Avail: NTIS HC A02/MF A01 CSCL 09C The traveling wave tube (TWT) has a slow wave structure (SWS) which is severed into two or more sections. A signal path connects the end of an SWS section to the beginning of the following SWS section. The signal path comprises an impedance matching coupler (IMC), followed by an isolater, a phase correcting filter, a variable phase shifter, and a second IMC. The aggregate band pass characteristic of the components in the signal path is chosen to reject, or strongly attenuate, all frequencies outside the desired operating frequency range of the TWT and yet pass with minimal attenuation in the forward N77-19320*# National Aeronautics and Space Administration. (NASA-Case-MSC-14939-1; US-Patent-Appl-SN-765165) Avail: NTIS HC A04/MF A01 CSCL 09C The present invention provides several improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas. (PITCH PLANE) 20 Y AXIS Author FILTER 47 N77-19319*# National Aeronautics and Space Administration. Goddard Space Flight Center, Greenbelt, Md. LOGARITHMIC CIRCUIT WITH WIDE DYNAMIC RANGE Paris H. Wiley (Va. Polytechnic Inst. and State Univ.) and Eugene A circuit deriving an output voltage that is proportional to the logarithm of a dc input voltage, and is susceptible to wide variations in amplitude was fabricated. A constant current source which forward biases a diode so that the diode operates in the exponential portion of its voltage versus current characteristic, above its saturation current is included. The constant current source includes first and second, cascaded feedback, dc operational amplifiers connected in a negative feedback circuit. An input terminal of the first amplifier is responsive to the input voltage. A circuit shunting the first amplifier output terminal includes a resistor in series with the diode. The voltage across the resistor is sensed at the input of the second dc operational feedback amplifier. The feedback voltage derived from the output of the second amplifier is subtracted by the first amplifier from the input voltage so that the current flowing through the resistor is proportional to the input voltage. NASA 24. 16 1521 A 12 22 X AXIS (ROLL PLANE) 13 14 N77-20341*# National Aeronautics and Space Administration. DIRECT CURRENT TRANSFORMER Patent Application A direct current transformer was built in which the primary consists of an elongated strip of superconductive material, across the ends of which is applied a direct current potential. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material. NASA |