Abstract: Interference from other users in a CDMA Spread Spectrum system is cancelled by constructing a single reference sequence which is representative of the spreading sequences of all users in the system. Interference from the other users can be cancelled without each receiver employing a separate decorrelator for every other user in the system and having an accurate estimate of the received power level of every transmitted signal.

Abstract: An enhanced nonlinear signal processor for RFI suppression using either biased null zone amplifier or a biased inverting limiter. Two or more nonlinear interference processors are connected in cascade. As a result, a deliberate tracking error, selected to provide only a small amount of relative interference rejection, is introduced into each processor. The effect of each stage is cumulative until some limit to performance improvement, determined by the input/output characteristic of each stage, is reached. The benefits of this discovery are increased dynamic range capability (higher levels of interference-to-wanted signal ratio can be fully rejected), simplification of gain control, and increased flexibility in hardware implementation options resulting from reduced sensitivity to RFI tracking error.

Abstract: A dual polarized printed circuit antenna operating in dual frequency bands. A first array of radiating elements radiates at a first frequency, and a second array of radiating elements radiates at a second, different frequency. Separate power divider arrays are provided for each array of radiating elements, and the overall structure is provided in a stacked configuration.

Abstract: A codec uses a number of different signal processing techniques to improve audio compression. These techniques include (1) dynamically varying the size of the processing block to match the duration of the signal over which the audio signal can be considered to be substantially constant, (2) reducing the power gain of the LPC coefficients to reduce leakage of coding noise from one block into the following block, (3) allocating bits to the residual signal in accordance with both objective and subjective criteria, and (4) computing a modified residual signal to take into account the zero input response of the synthesis filters to the reconstruction noise of past blocks.

Abstract: Method for randomly detecting a unique word comprising M bits in a predetermined number of segments within a frame containing L bits of data, where M and L are integers greater than one and wherein M is less than L, includes steps for (a) randomly sampling the data to thereby obtain the segments, (b) comparing a first segment of the segments with the first portion of an actual unique word so as to permit determination of a match between the first segment and the first portion of the actual unique word, (c) when a match is found between the first segment and the respective portion of the actual unique word, comparing a next segment of the segments with the next portion of the actual unique word, (d) when a match is found between the next segment and the next portion of the actual unique word, repeating step (c) until all of the segments are matched with corresponding portions of the actual unique word, and (e) when the comparison of any segment does not result in an appropriate match, returning to step (a) to

Abstract: A facsimile communication system including a first processing circuit, connected to receive a facsimile signal from a first facsimile device, for converting the analog voiceband facsimile signal into a digital code signal representing information carried in the analog voiceband signal, and for transmitting the digital code signal; a second processing circuit, connected to receive the transmitted digital code signal from the first processing circuit, for converting the received digital code signal into an analog voiceband facsimile signal; and a second facsimile device, connected to receive the analog voiceband facsimile signal from the second processing circuit. The digital code signal includes a digital code which is repeated in the digital code signal an integral number of times. In another embodiment, the digital code signal contains another binary code which represents the position, within a data field, when information was first detected by the first processing circuit.

Abstract: A method for compressing a multi-spectral data stream corresponding to an image for a selected one of transmission, as a limited bandwidth transmission using a predetermined band, and data storage includes steps for dividing the image into pixel blocks P in each of N bands, where both P and N are integers greater than one, selecting one of pixel blocks in one of N bands as an anchor band and computing prediction coefficients for relating intensities of each pixel in each P pixel block in the remaining N-1 bands based on the anchor band. A codec apparatus is also described.

Abstract: A common pressure vessel type Ni-H.sub.2 battery having a thermally conductive rack disposed within the pressure vessel and having an outer wall conforming to and in thermal contact with the inner surface of a cylindrical center wall portion of the pressure vessel and a plurality of fins dividing the rack into a plurality of compartments. A Ni-H.sub.2 battery cell is disposed in each of the compartments in thermal contact with adjacent ones of the fins. A plurality of flexure springs extend between racks, providing a radial force on the racks so as to urge the outer walls of the racks into contact with respective portions of the wall of the pressure vessel. A stopper is formed internally of the pressure vessel and a wave spring is disposed between a weld ring provided at the end of the rack opposite the stopper for forcing the racks in the longitudinal direction of the pressure vessel into contact with the stopper.

Abstract: An apparatus for and a method of permitting the in-band negotiation of enhanced capabilities between two or more facsimile interface units (FIUs) by using FIU capabilities control packets containing a plurality of data cells carrying information of the capability negotiation information is disclosed. In operation, a called station identification signal is transmitted from a remodulating FIU together with a special capabilities packet following the end of a line control packet. The calling FIU may issue a response agreeing to or modifying the compatible enhancements by sending its own special capabilities control packet containing compatibility negotiation information. In another aspect of the present invention, an FIU adds a set of data cells to a line control packet to minimize the possibility of data cell alignment due to degraded channel conditions.

Abstract: Before transmitting signals to a receiver, the signals are subjected to adaptive prediction to generate a residual signal for transmission, and the residual signal is then transformed into frequency domain coefficients, the coefficients are grouped together to form vectors, and the vectors are then quantized.

Abstract: A network of personal communications terminals communicating in a CDMA mode includes a reference station for transmitting a pilot tone that is pre-corrected at the reference station and is used at the remaining stations for frequency control, transmit power control and antenna acquisition and tracking. Voice activation is employed to permit the CDMA system to share the satellite transponder power and bandwidth in a fully Demand-Assignment-Multiple-Accessing (DAMA) manner. Burst-mode operation of a voice activated CDMA system is permitted by sending dummy data in the speech pausing period at a reduced (but not zero) power level, and the "near-far" problem inherent in a CDMA system is mitigated by the use of uplink power control.

Abstract: In a flat plate antenna, insertion loss is reduced significantly by providing an extensive waveguide structure at the back of the ground plane of the antenna. Depending on antenna size, the waveguide may feed the antenna at one or a plurality of points. According to a preferred embodiment, the transition from waveguide to stripline is made via a coaxial connection, with a quarter-wave transformation, including mode suppression walls to direct the energy more efficiently. Alternatively, a direct waveguide to stripline transition may be provided. The technique has wide applicability to a number of antenna designs, including single- and dual-polarization structures, and linear and circular polarization operation.

Abstract: Contactless coupling of a low-noise block down-converter (LNB) imbedded within a flat antenna is achieved by mounting the LNB on a power summing/combining network layer of the antenna, and coupling the transition capacitively to the power summing/combining network in a stripline-to-stripline transition. The contactless coupling facilitates antenna manufacture by allowing the rapid testing of the LNB and its final assembly into the antenna.

Abstract: Multifrequency signals are detected in a received signal by extracting filter coefficients from the received signal, generating line spectrum frequency (LSF) parameters from the filter coefficients, and processing the LSF parameters to identify multifrequency signals. The LSF parameters are first examined to see if the lowest frequency represented by the LSF parameters is below a predetermined frequency, e.g., 600 Hz, and if so it is determined that the signal is not a multifrequency signal. The parameters are next examined to see if there are exactly two sharp frequency spectrum peaks, with a sharp peak being defined by two consecutive LSF frequencies separated by less than some predetermined frequency range, e.g., 60 Hz. Assuming there are two peaks, the locations of the peaks are examined to see if they correspond to the possible tone pairs, thereby identifying a particular multifrequency tone.

Abstract: A video signal processor includes a motion vector estimation system having a first operating mode for performing frame-structure processing and a second operating mode for field-structure processing. The system includes N motion estimator units, each of the units receiving two respective time separated data blocks, wherein N units are operating during the first operating mode, wherein M of the N units are operating during the second operating mode and wherein (N-M) units provide motion estimating processing outside of an area of an image represented by the data blocks. According to one aspect of the present invention, N is an integer greater than 2 while M is an integer less than N.

Abstract: The steady state condition of a subject product is projected using transient data developed through actual or simulated tests or operations. The transient data represent the monotonic or cyclic property states of the product while subjected to environmental or operational conditions. A first and second property state value corresponding to the transient data for selected times within the test period are identified. A first and second rate-of-change value corresponding to the change in the property states at the selected times are then computed. A time constant value is next computed by applying the time interval and the first and the second rate-of-change values to a time constant function. A projected steady state condition value is next computed by applying the second rate-of-change value, the second state value and the time constant value to a projected steady state conditions function. The projected steady state condition value is compared with a previously computed projected steady state condition value.

Abstract: A communication system including: a first secure communication terminal for providing analog voiceband data; a first processing circuit connected to receive the secure data from the first secure communication terminal and for converting the received data into secure baseband data, the first processing circuit transmitting the baseband data; a second processing circuit connected to receive the transmitted baseband data from the first processing circuit, and for converting the received baseband data into analog voiceband data; and a second secure communication terminal for receiving the analog voiceband data from the second processing circuit. The communication system is especially applicable for handling secure data transmitted by a STU-III.

Abstract: A modem/codec is designed for a digital signal transmission system using a single satellite transponder. The system is capable of transmitting data of a rate of 155.52 Mbps, and is thus compatible with the BISDN rate. A codec of rate 13/15 is used, and an octal phase shift keying modem is also used. In this way, the digital signal transmission system is capable of receiving data at a rate of 155.52 Mbps over a single INTELSAT V/VA transponder with a usable bandwidth of 72 MHz.

Abstract: Improved automatic gain control for an amplifier is obtained by controlling the size of a null zone in a drive signal for the amplifier. The size of the null zone is controlled by estimating strength of an interference signal, and dynamically varying the size of the null zone based on the estimated strength of the interference signal. As a result, the amplifier rarely saturates, regardless of signal strength. The invention is useful to reduce the harmful effects of jamming or interference.

Abstract: A digital frequency upconversion and downconversion scheme for receivers and transmitters enables high resolution downconversion and upconversion, respectively, with low phase noise. A digital signal processor (DSP) receives temperature measurement information from a temperature transducer associated with a reference oscillator, and also receives channel tuning and other information. The DSP adjusts the signal samples accordingly, without adjusting the operation of the oscillator. Additionally, the inventive filtering scheme, preferably implemented in an application specific integrated circuit (ASIC), receives digital filtering coefficient information, digital symbol timing phase control signals, and, in some cases, other information from the DSP. As a result, the scheme enables operation at 1 Hz resolution, with phase noise which is at least 33.5 dB down at 10 Hz in the case of downconversion, and at least 42 dB down at 10 Hz in the case of upconversion.