Abstract: A method of controlling sampling frequency and sampling phase of a sampling device from a value generated by an equalizer coupled to the sampling device includes the steps of generating a complex representation of the value developed by the equalizer and generating a representation of a decision from an output of the equalizer. The complex representation and the decision representation are correlated to obtain a sampling error estimate. The sampling error estimate is used to adjust the sampling frequency and sampling phase of the sampling device.

Abstract: A digital receiver for processing a signal received from a channel includes a digital demodulator and an equalizer coupled to the digital demodulator. The equalizer includes a feedforward filter and a decision feedback equalizer (DFE), wherein the feedforward filter includes a plurality of feedforward filter taps. Coefficients are associated with the plurality of feedforward filter taps and the values of all of the coefficients associated with the plurality of feedforward filter taps are dynamically determined.

Abstract: A method of controlling a feedforward filter of an equalizer includes the steps of generating a complex representation of an output of the feedforward filter and generating a representation of a decision from an output of the equalizer. The complex representation and the decision representation are correlated to obtain a phase error estimate. A phase correction value is generated based on the phase error estimate and used to adjust the phase of the output of the feedforward filter.

Abstract: A digital receiver for processing a signal received from a channel includes a digital demodulator and an equalizer coupled to the digital demodulator. The equalizer includes a feedforward filter and a decision feedback equalizer (DFE), wherein the feedforward filter includes a plurality of feedforward filter taps. Coefficients are associated with the plurality of feedforward filter taps and the values of all of the coefficients associated with the plurality of feedforward filter taps are dynamically determined.

Abstract: A method of controlling sampling frequency and sampling phase of a sampling device from a value generated by an equalizer coupled to the sampling device includes the steps of generating a complex representation of the value developed by the equalizer and generating a representation of a decision from an output of the equalizer. The complex representation and the decision representation are correlated to obtain a sampling error estimate. The sampling error estimate is used to adjust the sampling frequency and sampling phase of the sampling device.

Abstract: A method of controlling a feedforward filter of an equalizer includes the steps of generating a complex representation of an output of the feedforward filter and generating a representation of a decision from an output of the equalizer. The complex representation and the decision representation are correlated to obtain a phase error estimate. A phase correction value is generated based on the phase error estimate and used to adjust the phase of the output of the feedforward filter.

Abstract: A system and methods for automatic digital certificate installation on network devices in a data-over-cable network are developed. One of the methods includes sending a digital certificate request from a cable modem to a predetermined network server upon determining on the cable modem that there is no digital certificate already installed on the cable modem. The method further includes generating at least one digital certificate on the network server and providing the at least one digital certificate to the cable modem.

Abstract: Methods for reducing interference from initializing network devices in a data-over-cable system. The method includes aligning Initial Maintenance intervals for multiple upstream channels of the data-over-cable system. A cable modem termination system determines if usage intervals for the upstream channels may accommodate Initial Maintenance intervals that start at a common time. If so, the cable modem termination system constructs Bandwidth Allocation MAP messages for the usage intervals that contain Initial Maintenance intervals timed to start at the common time. In response to the MAP messages, initializing network devices range when there are no scheduled data transmissions on any upstream channel. The method may shorten a cable modem's time for ranging and may decrease collisions with data transmissions on the upstream paths when cable modems try to initialize.

Abstract: Methods for reducing interference from initializing network devices in a data-over-cable system. The method includes aligning Initial Maintenance intervals for multiple upstream channels of the data-over-cable system. A cable modem termination system determines if usage intervals for the upstream channels may accommodate Initial Maintenance intervals that start at a common time. If so, the cable modem termination system constructs Bandwidth Allocation MAP messages for the usage intervals that contain Initial Maintenance intervals timed to start at the common time. In response to the MAP messages, initializing network devices range when there are no scheduled data transmissions on any upstream channel. The method may shorten a cable modem's time for ranging and may decrease collisions with data transmissions on the upstream paths when cable modems try to initialize.

Abstract: In a synchronous code division multiple access (SCDMA) system, a set of substantially orthogonal code words is selected such that each code word in the set of substantially orthogonal code words is minimally correlated with a channel characteristic such as noise. When a station transmits a data signal, it multiplies the data signal by its assigned code word in order to produce a spread data signal. The spread data signal is transmitted over the channel of the SCDMA system.

Abstract: A data transposition system reorders successive input groups of N data elements received in column order into corresponding output groups of data elements arranged in row order. The system includes a memory having N data element storage locations and a transposition address generator for repetitively generating a series of different sequences of address signals. The address signals of each sequence are sequentially applied to the memory for reading the data elements stored at the addressed storage locations for providing the output groups of data elements. Each read data element is replaced with the data element of the next input group corresponding in order to the order of the respective address signal within its associated sequence.

Abstract: The disclosed data processor develops a data signal which has a plurality of multi-level symbols. The data processor, in response to each of the symbols, determines the lowest path metric characterizing the data signal, and selects one of a plurality of sets of slice values in response to the lowest path metric. A slicer responds to the selected set of slice values by slicing the multi-level symbols. There may be only two sets of slice values in the plurality of sets of slice values, wherein each of the only two sets has three slice levels. Alternatively, there may be only five sets of slice values in the plurality of sets of slice values, wherein each of the only five sets has five slice levels. As a still further alternative, there may be only two sets of slice values in the plurality of sets of slice values, wherein each of the only two sets has a minimum of six slice levels.

Abstract: A first station encodes data as data symbols, rotates the data symbols so that data symbols corresponding to one another across sync portions of data segments of a frame are arranged to be processed together, and inserts the rotated data symbols into data portions of the data segments of the frame such that the frame has a plurality of data segments, wherein each data segment has a segment sync portion and a data portion. A second station processes the data symbols so that corresponding data symbols in a first set of data symbols are processed with a twelve data symbol delay and corresponding data symbols in a second set of data symbols are processed with a twenty-four data symbol delay depending upon the position of the data symbols in relation to the sync portions.

Abstract: A receiver for decoding encoded data transmitted by a transmitting station includes (i) sum and difference filters for filtering the encoded data and for providing corresponding sum and difference filtered outputs, (ii) first and second variable gain amplifiers for respectively controlling the sum and difference filtered outputs so as to provide corresponding sum and difference controlled filtered outputs that vary along a continuum in order to suppress co-channel interference and white Gaussian noise in the encoded data, and (iii) a Viterbi decoder for decoding the sum and difference controlled filtered outputs to recover uncoded data.

Abstract: A data receiver comprises a demodulator for recovering a received data signal comprising a stream of interleaved regularly spaced one-dimensional symbols of a phase invariant symbol constellation, each of the received symbols representing 3 bits, Z.sub.0, Z.sub.1, Z.sub.2 produced by convolutionally coding a first data bit X.sub.1 to derive bits Z.sub.0, Z.sub.1 and precoding a second data bit X.sub.2 to derive bit Z.sub.2. The received symbols are applied to a first decoder for estimating data bit X.sub.1 and a bit Y.sub.2, Y.sub.2 being applied to a postcoder for conversion to an estimate of data bit X.sub.2. The first decoder may comprise a Viterbi decoder or a 4-level slicer. In a preferred embodiment of the invention the received signal includes a plurality of regularly spaced synchronization intervals, each comprising a number of received symbols, and the second decoder is prevented from changing state during the synchronization intervals.

Abstract: A television signal is formatted for transmission by arranging a plurality of encoded data symbols, representing a plurality of source data bytes, into successive data frames each comprising 313 data segments. One of the data segments of each frame comprises a frame sync segment of which the last 12 symbols comprise a copy of the last 12 encoded data symbols of the preceding data segment. The remaining segments of each frame comprise 12 interleaved subsegments A-L, each subsegment comprising a plurality of encoded data symbols representing a contiguous group of sources data bytes, with the first symbol of each of the first 4 subsegments A-D comprising a predetermined segment sync symbol. The received signal is decoded by independently processing the symbols of each respective subsegment to derive estimations of the source data bytes.

Abstract: A trellis coded modulation system comprises a first coder for convolutionally coding a first input data bit X.sub.1 for deriving first and second output bits Z.sub.0 and Z.sub.1. A second coder precodes a second input data bit X.sub.2 for deriving an output bit Z.sub.2. The output bits Z.sub.0, Z.sub.1 and Z.sub.2 are mapped into corresponding one-dimensional multi-value symbols, wherein the output bits Z.sub.0, Z.sub.1 identify respective subsets of the symbols, each of the subsets comprising two equally spaced symbol values, and the output bits Z.sub.1, Z.sub.2 identify respective pairs of the symbols, each of the pairs comprising two adjacent symbol values.

Abstract: A trellis coded modulation system comprises a source of successive 2-bit data symbols X.sub.1, X.sub.2 arranged in a frame format wherein each frame comprises a plurality of data segments each including a plurality of groups of interleaved data symbols. Each group of interleaved data symbols is separately coded by a precoder and convolution encoder to derive coded output symbols Z.sub.0, Z.sub.1, Z.sub.2, which are mapped to respective 8-level symbols for transmission together with periodically generated frame and segment sync symbols. The received signal may be filtered by a linear filter, e.g. a comb filter, to reduce co-channel interference and each group of filtered symbols is applied to a respective first Viterbi decoder for estimating data bits X.sub.1 X.sub.2. Each first decoder preferably comprises a reduced complexity Viterbi decoder responsive to a partial representation of the state of the linear filter.

Abstract: A technique for enhancing the robustness of an ATV transmission system in the presence of NTSC or ATV co-channel interference comprises positioning the ATV signal relative to the co-channel NTSC/ATV signal to reduce interference into the ATV receiver. In a preferred embodiment, the ATV signal is positioned relative to a co-channel NTSC signal such that the demodulated difference f.sub.v -f.sub.p in the ATV receiver is equal to 70.5 f.sub.seg, where f.sub.v is the NTSC visual carrier frequency, f.sub.p is the ATV pilot carrier frequency and f.sub.seg is the ATV segment repetition rate, and relative to a co-channel ATV signal such that their respective pilot frequencies differ by an amount equal to 1.5 f.sub.seg.