| Patent Number |
Title Of Patent |
Date Issued |
| RE33189 |
Security system for SSTV encryption |
March 27, 1990 |
| In a secure communications system, a key number which is changed periodically, e.g. monthly, and a random number from a random number generator are combined and used as a seed to reset a PN sequence generator, with the output of the generator being used to control encryption of trans |
| 5594742 |
Bidirectional trellis coding |
January 14, 1997 |
| A block code decoding method finds the highest path metric path in a forward direction of a trellis diagram from an initial state of the trellis diagram to a final state. Next, the highest path metric path is found in a backward direction from the final state back to the initial stat |
| 5293330 |
Pipeline processor for mixed-size FFTs |
March 8, 1994 |
| A method is described for performing fast Fourier transforms (FFTs) of various sizes simultaneously in one pipeline processor. The processor consists of several stages of butterfly computational elements alternated with delay-switch-delay (DSD) modules that reorder the data between the |
| 5262794 |
Monolithic gallium arsenide phased array using integrated gold post interconnects |
November 16, 1993 |
| A monolithic gallium arsenide (GaAs) phased array using integrated gold (Au) posts for interconnecting multiple substrate layers. The phased array includes a GaAs substrate having transmit/receive modules fabricated on one side and radiating elements etched on the backside of the same |
| 5100745 |
Method for rejuvenating Ni-H.sub.2 batteries |
March 31, 1992 |
| A method for rejuvenating Ni-H.sub.2 battery cells suffering a voltage anomaly providing an improved cell output voltage and capacity. After the battery containing the cells suffering the voltage anomaly is removed from service, the battery is discharged. Discharging the battery reduces |
| 5005019 |
Electromagnetically coupled printed-circuit antennas having patches or slots capacitively couple |
April 2, 1991 |
| A printed-circuit antenna array having broadband linear polarization, and circular polarization with high polarization purity, feedlines of the array being capacitively coupled to feeding elements at a single feedpoint or at multiple feedpoints, the feeding elements in turn being ele |
| 4987386 |
Coherent phase and frequency recovery method and circuit |
January 22, 1991 |
| A coherent phase and frequency recovery method capable of rapidly recovering the phase and frequency of bursts of received signals from plural sources. The received signal is applied to a first input of a mixer, the output of which is amplified and applied to two feedback paths, one |
| 4978932 |
Microwave digitally controlled solid-state attenuator having parallel switched paths |
December 18, 1990 |
| An attenuator element has a reference path and a relative attenuation path. The reference path is formed by a T-network of two FETs operated in the passive mode and a shunt path and the attenuation path is formed with a similar structure, with the FETs in the shunt path having a differen |
| 4970592 |
Horizontal synchronization, clock synchronization, D.C. restoration and gain control scheme for |
November 13, 1990 |
| An analog TV system includes a transmitter which produces a horizontal unique pulse sequence during each horizontal blanking interval. The pulse sequence is amplitude modulated between two levels to define a horizontal unique word for horizontal synchronization. The frequency of the puls |
| 4967272 |
Bandwidth reduction and multiplexing of multiple component TV signals |
October 30, 1990 |
| In a system for transmitting analog video signals, the luminance and chrominance components are each subjected to different bandwidth reduction processes. In addition, the high and low frequency portions of the luminance component are subjected to different bandwidth reduction signal |
| 4943809 |
Electromagnetically coupled microstrip antennas having feeding patches capacitively coupled to f |
July 24, 1990 |
| A microstrip antenna array having broadband linear polarization, and circular polarization with high polarization purity, feedlines of the array being capacitively coupled to feeding patches at a single feedpoint or at multiple feedpoints, the feeding patches in turn being electromag |
| 4929959 |
Dual-polarized printed circuit antenna having its elements capacitively coupled to feedlines |
May 29, 1990 |
| A printed-circuit antenna enabling two signals to be received simultaneously. Two layers of radiating elements and corresponding power dividers are provided, one set of power dividers being disposed orthogonally with respect to the other, so as to enable reception of two signals with |
| 4926189 |
High-gain single- and dual-polarized antennas employing gridded printed-circuit elements |
May 15, 1990 |
| A gridded radiating element for printed circuit antennas employing capacitive coupling of radiating elements to feedlines. The radiating element is formed of a grid wherein a metallization region is etched selectively to yield a plurality of metal strips disposed parallel to each oth |
| 4912765 |
Voice band data rate detector |
March 27, 1990 |
| An apparatus for detecting the modulation rate of voice-band data signals. The detector determines the level occupancy L.sub.p, the partial entropy E.sub.p, and the zero-crossing count N.sub.zc for the input signal and compares these values with threshold values to determine the data rat |
| 4901349 |
Time dispersal encryption of TV signals |
February 13, 1990 |
| In encrypting a video signal for communications security, the horizontal synchronization pulses are removed, the active signal portions of each line in a field are delayed according to psuedorandom sequence of delays, and the reference color burst is moved to a position in the horizontal |
| 4866451 |
Broadband circular polarization arrangement for microstrip array antenna |
September 12, 1989 |
| The invention relates to a circular polarization (CP) technique and a microstrip array antenna implementing this technique. Using four microstrip radiating elements with proper phasing of the excitation in a 2.times.2 array configuration, the technique averages out the cross-polarize |
| 4852023 |
Nonlinear random sequence generators |
July 25, 1989 |
| Linear and nonlinear bits are logically combined to form each of at least three sequences, one of which is selectively used to couple either one of the others to the output of the sequence generator. |
| 4849998 |
Rate synchronized symbol timing recovery for variable rate data transmission systems |
July 18, 1989 |
| A symbol timing recovery circuit with a clock synchronization loop for variable rate data signals utilizes a frequency synthesizer for setting the frequency of the recovered clock signal. The received data signal, representing the modulating waveform of a transmitted modulated wareform, |
| 4829377 |
Horizontal synchronization, clock synchronization, D. C. restoration and gain control scheme for |
May 9, 1989 |
| An analog TV system includes a transmitter which produces a horizontal unique pulse sequence during each horizontal blanking interval. The pulse sequence is amplitude modulated between two levels to define a horizontal unique word for horizontal synchronization. The frequency of the puls |
| 4815130 |
Stream cipher system with feedback |
March 21, 1989 |
| A cipher system in which a key is initially inserted into a shift register and the serial output of the shift register is added to the plain text message and the sum is fed back into the serial input of the shift register. Parallel outputs of the shift register are led to a logic fun |
| 4811394 |
Variable starting state scrambling circuit |
March 7, 1989 |
| PN sequence generators used in the scrambling and descrambling circuits at remote locations are periodically preset to the same value in order to maintain synchronism, with the preset value being also periodically changed. The preset value can be transmitted to the scrambling and des |
| 4809334 |
Method for detection and correction of errors in speech pitch period estimates |
February 28, 1989 |
| A method of detecting and correcting received values of a pitch period estimate of a speech signal for use in a speech coder or the like. An average is calculated of the nonzero values of received pitch period estimate since the previous reset. If a current pitch period estimate is w |
| 4797918 |
Subscription control for television programming |
January 10, 1989 |
| A method and apparatus for one-way subscription television service control which allows the subscribers to subscribe in advance to a variety of programming or to select programming oa a pay-per-view basis. |
| 4792963 |
Satellite clock system |
December 20, 1988 |
| A satellite clock system in which the frequency of the onboard satellite clock, which is implemented as a relatively high uncertainty voltage-controlled oscillator, is corrected in accordance with a high-stability, low-uncertainty terrestrial clock. Metering bursts are transmitted fr |
| 4776540 |
Method of orienting a synchronous satellite |
October 11, 1988 |
| The invention is a method of orienting a satellite in a geosynchronous orbit so as to direct a beam from an antenna mounted on the satellite to cover a desired target site, and pointing the beam axis at a desired bore site target. One embodiment of the method according to the invention |
| 4774705 |
Switch matrix with acoustic delay for TDMA signal storage on-board a satellite |
September 27, 1988 |
| A switch matrix with a delay feature for temporary storage of burst communications on-board a satellite. Additional input and output ports are added to a conventional switch matrix in such a manner that, if delay is desired, the additional output ports loop their output signals through |
| 4761654 |
Electromagnetically coupled microstrip antennas having feeding patches capacitively coupled to f |
August 2, 1988 |
| A microstrip antenna array having broadband linear polarization, and circular polarization with high polarization purity, feedlines of the array being capacitively coupled to feeding patches at a single feedpoint or at multiple feedpoints, the feeding patches in turn being electromag |
| 4751736 |
Variable bit rate speech codec with backward-type prediction and quantization |
June 14, 1988 |
| In an adaptive differential PCM (ADPCM) system transmitter, three quantizers provide, respectively, 3, 4, and 5-bit quantization at the signal sampling rate. Each quantizer produces, in response to an input signal sample, a coded signal I(n) in the form of a bit sequence the number o |
| 4645883 |
Double talk and line noise detector for a echo canceller |
February 24, 1987 |
| An echo canceller comprising an adaptive finite impulse response filter receiving a receive signal and having its output subtracted from a send signal, a non-linear device for attenuating low level signals of the send signal and a noise injector for injecting noise into the send signal |
| 4637017 |
Monitoring of input backoff in time division multiple access communication satellites |
January 13, 1987 |
| A method of measuring input-backoff to an amplifier in a time-division multiple access (TDMA) communication system having a carrier recovery segment and a clock recovery segment prior to a data segment in a traffic burst. A monitoring station transmits a CW pilot signal within the am |
| 4636753 |
General technique for the integration of MIC/MMIC'S with waveguides |
January 13, 1987 |
| A technique for packaging and integrating of a microwave integrated circuit (MIC) or monolithic microwave integrated circuit (MMIC) with a waveguide uses a printed conductive circuit pattern on a dielectric substrate to transform impedance and mode of propagation between the MIC/MMIC and |
| 4609787 |
Echo canceller with extended frequency range |
September 2, 1986 |
| An echo canceller with extended frequency range for acoustic echoes comprising an adaptive finite impulse response filter receiving the receive signal below a cross-over frequency and predicting the echo of this signal across the echo path, a subtractor for subtracting the predicted |
| 4602965 |
Method of making FETs in GaAs by dual species implantation of silicon and boron |
July 29, 1986 |
| A method of preparing an active surface layer on a semi-insulating GaAs substrate comprising the steps of ion implanting a surface layer with silicon to form an n-type active layer and ion implanting a buried diffusion layer beneath the active layer with boron to prevent defects in t |
| 4602375 |
Onboard clock correction by means of drift prediction |
July 22, 1986 |
| In an on-board satellite clock correction system of the type wherein phase errors between the satellite clock and a ground-based clock are determined and a clock correction value sent to the satellite, the clock correction value is determined by curve-fitting the determined phase errors |
| 4600815 |
Automatic gain control for echo cancellers and similar adaptive systems |
July 15, 1986 |
| An echo canceller for a teleconferencing device is herein disclosed in which a first attenuator limits the dynamic range of a composite speech-echo input signal. A second attenuator, having a gain equal to that of the first attenuator, alters the gain of the emulated echo signal prod |
| 4595929 |
Scheme for aberration correction in scanning or multiple beam confocal antenna system |
June 17, 1986 |
| A frequency conversion interface is disposed between the main and subreflectors in a multiple beam antenna system so that the antenna system amplification factor will be defined by m=(f.sub.1 /f.sub.2).multidot.(.omega..sub.1 /.omega..sub.2), to permit large main reflector to subrefl |
| 4591812 |
Coplanar waveguide quadrature hybrid having symmetrical coupling conductors for eliminating spur |
May 27, 1986 |
| A coplanar waveguide quadrature hybrid is herein disclosed which produces even E-field symmetry about the center line of transmission during both even-and odd-mode excitation. In a first embodiment of the present invention, a first coupling element of a generally elongated shape is b |
| 4585711 |
Hydrogen electrode for a fuel cell |
April 29, 1986 |
| A hydrogen electrode and the method of making the electrodes usable in a fuel cell comprising a perforated nickel foil current collector, the back side of which is sealed with a semi-permeable membrane of polytetrafluoroethylene (PTFE) with a thickness of 50 .mu.m and a pore diameter |
| 4583078 |
Serial Viterbi decoder |
April 15, 1986 |
| A serial Viterbi decoder in which a single set of circuits is sequentially used for all the encoder states to calculate the maximum probability path, as measured against received signals, of unencoded signal sequences to reach each encoder state. The path to any encoder state having the |
| 4581736 |
Multiple downlink data aggregator and system |
April 8, 1986 |
| In a TDMA satellite communications system with a plurality of transponders and a network of satellite communication controller (SCC) terminals, a data aggregator which may be attached to a local SCC. The data aggregator simultaneously receives TDMA frames from at least two transponders a |
| 4519080 |
Analog threshold decoder |
May 21, 1985 |
| A modified Type I decoder generates analog syndrome bits from a selected combination of analog signals representing bits yet to be decoded and digital signals representing already decoded information bits. A selected combination of analog syndrome bits is used to generate a weighted |
| 4501001 |
Variable slope delta coding processor using adaptive prediction |
February 19, 1985 |
| A variable slope delta coding processor using adaptive prediction in which a digitized signal is transmitted with approximately half the channel bandwidth required by previous techniques without any substantial sacrifice of received signal quality. An estimate of a digital sample is |
| 4500856 |
Simplified minimum shift keying modulator |
February 19, 1985 |
| An MSK modulator having a simple construction with only a single necessary adjustment. The digital bit stream to be modulated is fed directly to the control input of a 0,.pi. phase shifter in a single-sideband modulator. A phase shift circuit is used to couple an IF signal to the IF sign |
| 4500842 |
Adaptive gain variable bit rate NIC processor |
February 19, 1985 |
| An adaptive gain control is provided at the input of a Variable Rate Nearly Instantaneous Companding (VRNIC) processor to adjust the gain of low level speech signals so that the transmission bit rate and SNR will remain substantially the same for low signal levels as for high signal leve |
| 4484027 |
Security system for SSTV encryption |
November 20, 1984 |
| In a secure communications system, a key number which is changed periodically, e.g. monthly, and a random number from a random number generator are combined and used as a seed to reset a PN sequence generator, with the output of the generator being used to control encryption of trans |
| 4477785 |
Generalized dielectric resonator filter |
October 16, 1984 |
| A generalized dielectric resonator filter is disclosed for the realization of the most general transfer function characteristics of band-pass filters using cylindrical dielectric resonator discs in a microstrip transmission line configuration. The dielectric resonator filter of the inven |
| 4475211 |
Digitally controlled transversal equalizer |
October 2, 1984 |
| An adaptive equalizer performs equalization at IF, demodulates the input signal and then generates the equalization coefficients at baseband from the demodulated data. Coefficient updating can be done on a non-real time basis and coefficients for individual bursts stored in a coefficient |
| 4472817 |
Non-PLL concurrent carrier clock synchronization |
September 18, 1984 |
| Concurrent carrier and clock synchronization are derived from an input signal in interdependent loops without the use of phase look loop (PLL) circuitry in order to improve operation at higher bit rates. An acquisition detection signal is generated only in response to predetermined m |
| 4470148 |
Satellite-receiver time division multiple-access burst duration and guard space monitor |
September 4, 1984 |
| A burst duration and guard space monitor circuit which produces burst duration and guards space signals which are substantially unaffected by nulls or near nulls in a received QPSK signal. The received QPSK signal is compared with a fixed threshold voltage. The comparison output is sampl |
| 4470146 |
Adaptive quantizer with instantaneous error robustness |
September 4, 1984 |
| A robust ADPCM encoder with a modified leaky quantizer and a pair of parallel predictors is provided. A large leakage is initially inserted into the quantization scale adaptation by utilizing a number of most recent multipliers in a modified leaky Jayant quantizer. Using a dual predi |
