Abstract: A combination of two phase-lock loops, and a cancellation circuit are used to remove a dominant FM signal from within a signal environment. The two phase-lock loops together produce a replica of the highest power (i.e. dominant) FM signal. The cancellation circuit uses this replica in a demodulation, notch-filtering, and remodulation process to excise the dominant FM signal, leaving the other signal(s) undisturbed. Potential applications include co-channel FM signal/interference cancellation and optimizing utilization of RF spectrum.

Abstract: A ball bearing/freewheel clutch is provided with an inner race member defining an inner race surface; an outer race member defining an outer race surface concentric with said inner race member; and a raceway between said inner and outer races. The inner and outer race members each have a series of short radially oriented sawtooth inclines on their respective inner and outer race surfaces at right angles to said raceway. A plurality of modified ball bearings are disposed in said raceway between said inner and outer race members, such that said modified ball bearings serve to prevent relative rotation of said inner and outer race members in one direction, and to transmit a torque between said inner and outer races. In the preferred embodiment of the invention, said modified ball bearings have flattened poles which engage said sawtooth inclines in one direction of rotation.

Abstract: A method and apparatus for detecting and measuring the code phase offset in bits and fractional bits, or the time delay in master clock cycles, between a reference binary pseudo-noise (PN) code sequence and a similar sequence of unknown delay. Rapid detection and measurement is achieved by utilizing parallel feed-forward logic and eliminating all feedback and variable delay circuitry. At the start of a new detection and measurement cycle, the current state of the A input sequence is stored and correlated with new B input stakes. Likewise the state of the B input sequence is stored and correlated with a new A input code states. After a time equal to the delay between the two input sequences, one of the correlators will produce an output. A time delay counter runs from the start of a new detection and measurement cycle and stops on the occurrence of a correlator output.

Abstract: In a cellular system configuration, the location of a mobile station is determined from the acquisition of cellular network data pertaining to the mobile station, and the translation of such network data into a corresponding geographical position profile. The cellular system includes a mobile station locator entity for receiving from a mobile switching center the network data such as cell and/or sector ID and trunk group member number. The mobile station locator translates the network data into position information such as geographic coordinates (latitude and longitude), resolution (radius), and angle values for sectorized cells.

Abstract: A video coding scheme based on wavelet representation performs motion compensation in the wavelet domain rather than spatial domain. This inter-frame wavelet transform coding scheme preferably uses a variable-size multi-resolution motion compensation (MRMC) prediction scheme. The MRMC scheme produces displaced residual wavelets (DRWs). An optimal bit allocation algorithm produces a bit map for each DRW, and each DRW is then adaptively quantized with its respective bit map. Each quantized DRW is then coded into a bit stream.

Abstract: A network interface module operably connected to a subscriber's television receiver and to a switched broadband digital network includes a fiber-compatible digital transceiver. A downlink receiver in the transceiver detects video/audio/data information that is time-multiplexed within a serially transmitted digital signal optically transmitted by the switched digital network as a broadband digital downlink channel. The detected information is decoded into a parallel format of video/data samples, audio samples, and recovered sample clock that are applied to a digital switch in the television receiver.

Abstract: A novel variable-size block multi-resolution motion estimation (MRME) scheme is presented. The motion estimation scheme can be used to estimate motion vectors in subband coding, wavelet coding and other pyramid coding systems for video compression. In the MRME scheme, the motion vectors in the highest layer of the pyramid are first estimated, then these motion vectors are used as the initial estimate for the next layer and gradually refined. A variable block size is used to adapt to its level in the pyramid. This scheme not only considerably reduces the searching and matching time but also provides a meaningful characterization of the intrinsic motion structure. In addition, the variable-MRME approach avoids the drawback of the constant-size MRME in describing small object motion activities. The proposed variable-block size MRME scheme can be used in estimating motion vectors for different video source formats and resolutions including video telephone, NTSC/PAL/SECAM, and HDTV applications.

Abstract: An Asynchronous Transfer Mode (ATM) cell alignment assembly aligns an incoming ATM cell within an internal time slot of an ATM matrix by controllably time-delaying the cell before being switched by the matrix. The alignment assembly includes a 53-byte-wide shift register having a serial input receiving the incoming ATM cell, and fifty-three parallel outputs each coupled to a respective input of a 53.times.8 programmable crosspoint switching array. Each output of the array is coupled to an input of a shift register having eight parallel inputs and a serial output coupled to a respective input of the ATM matrix. The crosspoint switching array establishes only a single selected switching path through the array in accordance with the desired time delay, and is reconfigured upon the arrival of each incoming ATM cell.

Abstract: A satellite communication system in which a satellite receives a signal on a uplink carrier frequency, frequency translates it, and transmits the signal at a downlink carrier frequency. The downlink carrier frequency differs from the uplink carrier frequency by a standard frequency offset and a frequency offset error. A terminal earth station transmits to the satellite an inbound signal on the uplink carrier frequency. A hub earth station continually transmits to the satellite an outbound signal on an uplink carrier frequency and receives from the satellite the outbound signal at the downlink carrier frequency. The hub strips the outbound signal from the downlink carrier frequency and compares the stripped downlink carrier frequency to the reference carrier. A frequency offset error signal corresponding to the frequency offset error is generated.

Abstract: Circuit for recovery of a plurality of multipath direct sequence spread spectrum signal components received over a time span, wherein the multipath signal components are components of a signal generated from digital data comprised of data bits at a data bit rate modulated by a pseudo-noise code, consisting of a sequence of chips having a chip rate greater than the data bit rate, wherein the sequence of chips is a code repetition period equal or greater than the received time span of the multipath signal components. A plurality of correlators is provided. Each correlator has a first input for coupling to the multipath signal components, a second input, and an output. A pseudo-noise code generator generates a duplicate of the pseudo-noise code. A time delayer is coupled between the second inputs of a mulitiplicity of the correlators and the pseudo-noise code generator for delaying the duplicate of the pseudo-noise code by a multiple of a time delay equal to the time of a chip duration or less.

Abstract: A coupling network for coupling a signal at a frequency from a voltage source to a load. The voltage source has a source resistance. The load has a load resistance and a load reactance. The ratio of the load reactance to the load resistance greater than 100. The coupling network includes a reactive element and a delay circuit. The reactive element is arranged in series with the load to resonate with the load reactance at the frequency. The delay circuit is between the reactive element and the source, has a delay equivalent to a quarter wave length transmission line at the frequency and has a characteristic impedance equal to the square root of the product of the values of the load resistance and the source required resistance.

Abstract: Method of demodulating a signal including a plurality of time-dispersed signal components such as resulting from receiving in a multipath environment. A plurality of correlators are provided. The period of expected time uncertainty is scanned to identify the highest energy signal components. Each correlator is assigned to process one of the highest energy signal components. Each of the correlator outputs is pase corrected to compensate for carrier phase differences. The correlator outputs are coherently combined to provide a data output.

Abstract: Isochronous interface apparatus for transferring data from a source over a clocked channel to a destination. A channel input interface is interposed between the source and the channel. The channel input interface includes a data compressor adapted to compress the data with a compression ratio responsive to a signal. A first elastic buffer is coupled between the data compressor and the channel, having a first variable stack and providing a first signal representing the depth of the first variable stack. The first elastic buffer has an input coupled to the data compressor and has an output clocked by the channel and provides a signal representing the depth of the variable stack. The first signal is feedback to the data compressor for controlling the compression ratio of the data compressor. A channel output interface is interposed between the clocked channel and the destination. The channel output interface includes a data expander coupled to the channel.

Abstract: Method of transferring isochronous data from a source over a clocked channel to a sink. The data is compressed by a compression ratio responsive to a depth of a first variable stack. The compressed data is stored in the first stack and clocked by the channel. Compressed data on the channel is expanded and stored in a second variable stack. The variable stack is clocked to maintain the second variable stack at a constant depth.

Abstract: A correlator for processing a direct sequence spread spectrum communication system signal, wherein digital data comprised of data bits at a data bit rate is modulated by a first pseudo-noise code comprised of a sequence of chips having a pseudo-noise chip rate greater than the data bit rate, each chip having a chip period, the sequence repeating at a code period, and the pseudo-noise modulated data modulates a carrier resulting in the signal. A sampler produces digital samples of the signal. A pseudo-noise code generator produces a second pseudo-noise code replicating the first pseudo-noise code. Circuity time syncronizes the second pseudo-noise code to maximize a combined value of correlated signal energy, thereby time locking the first pseudo-noise code and the second pseudo-noise code.

Abstract: Method of processing a direct sequence spread spectrum communication system signal wherein digital data comprised of data bits is modulated by a first pseudo-noise code comprised of a sequence of chips, the pseudo-noise chip rate greater than said date bit rate, each chip having a chip period, said sequence repeating at a code period, and the pseudo-noise modulated data modualates a carrier frequency resulting in the signal. Digital samples are made of the signal. A second pseudo-noise code replicates the first pseudo-noise code. A first correlation is made of the sampled signal and the second pseudo-noise code. A second correlation is made of the sampled signal and the second pseudo-noise code delayed by one chip period. A first correlated signal energy value represents the signal energy of the first correlation. A second correlated signal energy value represents the signal energy of the second correlation.

Abstract: Apparatus for indicating the end of an acquisition procedure between a transmitter and receiver in a direct sequence spread spectrum communications system. A transmitter generates a first acquisition code having a first acquisition code period and comprised of digital bits at a first bit rate. A circuit modulates the first digital acquisition code by a pseudo-noise code repeating at a pseudo-noise code period and consisting of a sequence of chips at a chip rate greater than the first bit rate. The first acquisition code period is an integer multiple of the pseudo-noise code period. A circuit modulates a carrier by the first digital acquisition code modulated by the pseudo-noise code. The carrier modulated by said first digital acquisition code modulated by said pseudo-noise code is transmitted for a first period of time. A circuit synchronizes a receiver to the chip rate and carrier frequency. A circuit synchronizes the receiver to the pseudo-noise code period.

Abstract: Method for indicating the end of an acquisition procedure between a transmitter and receiver in a direct sequence spread spectrum communications system. At a transmitter, a first acquisition code having a first acquisition code period and comprised of digital bits at a first bit rate is generated. The first digital acquisition code is modulated by a pseudo-noise code repeating at a pseudo-noise code period and consisting of a sequence of chips at a chip rate greater than the first bit rate, and wherein the first acquisition code period is an integer multiple of the pseudo-noise code period. A carrier frequency is modulated by the first digital acquisition code modulated by the pseudo-noise code. The carrier is modulated by the first digital acquisition code modulated by the pseudo-noise code is transmitted for a first period of time.

Abstract: A sonar system has at least two separated bottom-mounted acoustic modules, each module including a projector for generating horizontal sound beam, a vertical line receive array for monostatic and bistatic detection, and a high frequency, upward-directed transducer for providing a steerable vertical beam to ensure full water column coverage by the use of surface reflections to minimize shadowing caused by high relief bottom topography.

Abstract: Method for carrier frequency correction in a direct sequence code division multiple access communication system having a carrier frequency, consisting of an expected carrier frequency and a carrier frequency error, modulated by a pseudo-noise code. A local frequency is produced equal to the expected carrier frequency. Received signals are demodulated of the pseudo-noise and mixed with the local frequency. The demodulated signals consist of in-phase signal components and quadrature signal components and the carrier frequency error. Each of the demodulated signal are converted to digital samples. Each signal digital sample is multiplied by stored digitized samples of a plurality of sinusoidal tones to produce a product corresponding to each tone. Each product corresponding to each tone is squared. The resulting squared products are compared to determine which squared product has the maximum value.