Tachyon, Inc.

M/a-Com Government Systems, Inc.

Tachyon Networks Incorporated

Future Wei Technologies, Inc.

Cable/home Communication Corp.

M/a-Com Linkabit, Inc.

Titan Linkabit Corporation

Torrey Science Corporation

Huawei Technologies Co., Limited

Karl E Moerder

Bruce L Carneal

Steven H Bradshaw

Michael J Theiss-Aird

Min Zhu

Gordon Kent Walker

Li Zhang

Paul Moroney

Klein S Gilhousen

Xiaolong Zhang

Liming Fang

Donald Wesley Becker

Jim Chen

John L Moran, Iii

Ron D Katznelson

Marc L Morrissette

Sean Yang

Charles F Newby, Jr

John Leo Iii Moran

A coaxial cable tap comprises a housing, and a faceplate coupled to the housing. The faceplate comprises a first directional tap port, and a diagnostic reverse (DR) port configured to receive a first upstream signal originating downstream from the coaxial cable tap, and inject a downstream test signal in a downstream direction. A hybrid fiber-coaxial (HFC) network comprises a headend, a first amplifier coupled to the headend, and a tap coupled to the first amplifier, configured to couple to a plurality of cable modems (CMs), and comprising a diagnostic forward (DF) port configured to receive a downstream signal originating from the first amplifier, and inject an upstream test signal in an upstream direction for reception at the headend.

Reverse-direction tap (RDT), remote diagnostic management tool (RDMT), and analyses using the RDT and the RDMT

A communication system comprising three communication resources: a contention-type access block, a non-contention access block and a second non-contention access block called a reserved block. Each time that a remote unit has a block of data to transfer to a hub station, it sends the block of data over the contention-type access block. It also sends a corresponding notification message over the reserved block. If the hub station receives the notification message but not the block of data, it sends a response message to the remote unit which designates a resource within the non-contention access block. The remote unit then sends the block of data to the hub station over the designated resource.

Method and apparatus for multiple access in a communication system

In a system in which multiple remote units compete for limited communication resources, a remote unit accesses the system by randomly selecting a first sequence from a set of predetermined sequences. The remote unit transmits a data bit stream modulated with the first sequence beginning at one of a set of recurring admission boundaries. If the remote unit determines that the data bit stream has not been successfully received at a hub station, it randomly selects a second sequence from the set of predetermined sequences. The remote unit transmits the data bit stream modulated with the second sequence beginning at one of the set of recurring admission boundaries.

Method and apparatus for a CDMA random access communication system

A communication system extracts a received modulation frequency from baseband modulation. This frequency is used as a reference to control the output of a variable oscillator. The output of the variable oscillator may be used to generate a transmit upconversion frequency, and may also be used to perform a downconversion from IF to baseband during receive operations.

Frequency generation in a wireless communication system

Time alignment of a signal from a remote unit at a hub station of a multiple access system is achieved based upon an initial time indication received from the hub station at the remote unit via a satellite. The remote unit transmits a signal to the satellite, monitors for a retransmission of the signal from the satellite and measures the time difference between the outgoing and incoming signals. The remote unit, then, uses the time difference to more finely adjust the time alignment. Alternatively, the remote unit transmits a first signal advanced with respect to an on-time estimate to the hub station and receives a responsive energy indication from the hub station. The remote unit transmits a second signal delayed with respect to the on-time estimate to the hub station and receives a responsive energy indication from the hub station. The remote unit compares the two energy indications and adjusts the on-time estimate. In another embodiment, the remote unit receives a compensated time indication from the hub station. The remote unit compares the time indication with the time at which the indication was actually received based upon a local, accurate time reference. The remote unit sets a transmission timer equal to the current time indicated by the local reference advanced by the difference between the time indication and the time which the time indication was received.

Method of and apparatus for time synchronization in a communication system

Transmission of TCP/IP data over a satellite link from a hub station to a plurality of remote units. The data, transmitted over the satellite link, uses the digital video broadcast (DVB) protocol. A field in the DVB header is used to indicate the location of the start of a new TCP/IP data packet within the DVB data. Use of a field in the DVB header to indicate the location of the start of a new TCP/IP data packet supports variable location of TCP/IP data within a DVB frame, and therefore more efficient use of the DVB bandwidth.

Transmission and reception of TCP/IP data over a wireless communication channel

When an installed wireless remote unit is operating in the field, routine operation is interrupted to enter a calibration mode. In calibration mode, the compression point of a circuit element is determined by applying a series of different drive levels to the circuit element. Based upon the determination of the compression point, a maximum transmission point is selected for the remote unit. Upon resumption of normal operation, the remote unit uses the maximum transmission point to limit the signal power level transmitted over the wireless link. As time passes or operating conditions change, the calibration process is re-executed.

Method and apparatus for calibration of a wireless transmitter

In systems for reading pixel data from an array of horizontal m-bit rows of CCD image detectors, pixel data loaded in parallel from a row of the array into an m-bit shift register is transferred in parallel from the m-bit shift register into other data storage device(s) having a plurality of output ports and sensed by a plurality of output amplifiers respectively connected in parallel to the output ports of the other data storage device(s). In a parallel-output-serial-register system in which the m-bit serial shift register has n cells at one end of the m-bit shift register that respectively have n output ports and an output register having n cells respectively connected in parallel to the n output ports of the m-bit shift register, with a plurality of different cells of the output register respectively having output ports, the loaded pixel data is shifted through the shift register toward the n output ports thereof and the shifted pixel data is transferred in parallel from the n output ports of the shift register into the n cells of the output register for sensing by output amplifiers respectively connected to the output ports of the output register.

Readout of pixel data from array of CCD image detectors

A phase accumulator for accumulating digital frequency words, which, as accumulated, represent the phase of a cyclic waveform of a predetermined frequency. The phase accumulator includes a coarse-component accumulator for accumulating coarse phase components of the digital frequency words; a fine-component accumulator for accumulating fine phase components of the digital frequency words; and means for incrementing the coarse-component accumulator in response to accumulation of the fine phase components. The incrementing means include means for providing a variable randomly generated value for each fine-component accumulation cycle; means for periodically sampling the accumulation of the fine phase components in relation to the randomly generated value; and means for incrementing the coarse component register for each fine-component accumulation cycle, with the phase of said incrementing being dithered in accordance with the number of times the accumulated fine phase components exceed the randomly generated values during the sampling period.

Phase accumulator with dithered incrementing of accumulation due to fine

A system for companding digital audio signal samples processes the digital audio signal samples to correct errors induced by the compression and expansion processes. These errors are calculated prior to compressing the samples. Such errors are calculated in accordance with a predetermined compression process and a predetermined expansion process; and the digital audio signal samples are corrected in accordance with such calculations prior to compression. The compression process includes providing a 3-bit gain word for a block of 70 samples. The gain word is computed in accordance with the position of the most significant '1' bit in the sample(s) having the peak magnitude. Each individual sample is processed in accordance with the block gain word to compress the sample by reducing the number of magnitude bits. The error calculation process includes calculating an error signal by subtracting a calculated reproduced digital audio signal sample from the digital audio signal sample to be compressed, filtering the error signal by noise-spectral filtering and adding the filtered error signal to the next-providing digital audio signal sample to provide a corrected digital audio signal sample for compression. The error calculation process also includes calculating an error value based upon the effect of using a single gain word for compressing a block of samples. The error value is subtracted from the corrected digital audio signal sample prior to compression. The gain word is forward error corrected by (5,1) encoding to enable detection and correction of both single-bit and double-bit errors in transfer by majority voting. The sign bit and the most significant magnitude bits of the compressed samples are forward error corrected to enable detection and correction of single-bit errors in transfer and to enable detection and concealment of double-bit errors in transfer.

Digital audio companding and error conditioning

A system for reproducing in a descrambler of a subscriber communication network a subscriber key signal that is unique to the descrambler and was used in encrypting a key signal that must be decrypted for use in descrambling a signal received by the descrambler. The scrambled signal is received by the descrambler together with the encrypted key signal and a key generation number containing an address for accessing a predetermined area in a memory contained in the descrambler. The system includes a circuit for providing a subscriber key generation signal that is unique to the descrambler; a subscriber key generator for reproducing the unique subscriber key signal by processing the subscriber key generation signal in accordance with a predetermined encryption algorithm upon the algorithm being keyed by a prescribed subscriber key seed signal that is unique to the descrambler; a secure memory storing a plurality of different subscriber key seed signals, and for providing the prescribed seed signal to key the algorithm when the area of the memory containing the prescribed seed signal is accessed by the address contained in the received key generation number; and a circuit for accessing the first memory with the address contained in the received key generation number. The subscriber key generation signal is formed by combining the received key generation number with a unique subscriber address signal that is stored in a second memory of the descrambler.

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Poway, CA, United States of America

Karl E Moerder