Abstract: Upon reception of the group ID and sound volume control signal, a selecting means refers to a control group ID management memory to determined whether the part being supplied belongs to the received group ID or not. When it is determined that the part being supplied belongs to the received group ID, the selecting means transmits the sound volume control signal supplied to the control means. The control means receives this sound volume control signal received from the selecting means and executes the process corresponding to the sound volume control signal for the supplied signal (MIDI signal or audio signal) and then outputs such sound volume control signal. As explained above, the control manipulation in the receiving side can be simplified.

Abstract: During the synchronization, a first, analog carrier signal (bs) exhibits a predetermined phase position at least temporarily. A further reference carrier signal (rs) is modulated with the same prescribable phase position, the phase difference between the two modulated carrier signals (bs, ts) is identified and, subsequently, the phase position of the reference carrier signal (rs) is corrected by the identified phase difference. As a result thereof, the phase difference is identified and corrected very fast. The inventive method is advantageously utilized in the demodulation of high bit rate carrier signals (bs) particularly carrier signals (bs) transmitted burst-like.

Abstract: An adaptive trellis adaptable to read a signal having signal amplitude dropouts includes a standard partial response maximum likelihood (PRML) trellis and an estimating PRML trellisd. The standard trellis is associated with a standard state diagram having standard branches between states. The estimating trellis is associated with an estimating state diagram having estimating branches between states. Each branch has an associated error metric. Each state of the standard state diagram has two estimating branches feeding into that state and each state of the estimating state diagram has two standard branches feeding into that state. The states are connected by paths formed by branches between the states. A path error metric is the sum of all branch error metrics for all of the branches that form the path. The path arriving at one state having the lowest error metric is the expected path to the next state for reading the signal.

Abstract: A channelized filter design for partial band reconstruction having high dynamic range requirements. The analysis filter and synthesis filter constraints permit high performance signal detection with an alias free signal recombination capability for signals that span multiple frequency bins. The filter bank allows the use of a single wideband asset to provide for data channelized for detection processing with the ability to recombine one or more adjacent frequency bins into a wider bandwidth baseband time domain data stream suitable for exploitation processing. Use of an efficient partial band reconstruction mechanism allows signal reconstruction using only the frequency subchannels that pertain to the signal of interest that is to be copied. The filter design mechanism separates the specification of the analysis filter to support signal detection in environments of high dynamic range. The signal reconstruction (synthesis) filter uses fewer bins and allows a higher order filter.

Abstract: A frequency diversity digital wireless transmission system and method according to which a number of relatively narrow bands are established, each using multiple averaging interpolators. The serial data bits are divided by a predetermined pattern among the frequency bands providing frequency diversity. In response to one or more of the bands being lost to multipath fading or interference, the interpolated signals of the remaining bands are used.

Abstract: The present invention provides an excellent waveform equalization apparatus and its method realizing a PR1 equalizer reducing circuit scale and reducing power consumption. It is known that in a high frequency region proximate to Nyquist frequency, emphasis of an amplitude characteristic is smaller in Class 1 (PR1) than in Class 4 (PR4) of Partial Response. Hence, there is constituted a waveform equalizing apparatus satisfying PR1 equalization reference by a combination of an integrator for low frequency region emphasis and a filter constituted for PR4. By such a constitution, circuit scale can be reduced more than that of conventional PR1 equalizer and power consumption can be reduced.

Abstract: A reverse link modulator modulates the incoming data sequence for the I and Q channels of a wireless device such that the resulting spreading sequence never undergoes a transition through the origin. Consequently, the modulator has a reduced peak-to-average ratio and provides an improved battery life.

Abstract: The present invention is a time recovery circuit and method for synchronizing timing of a signal in a receiver to timing of the signal in a transmitter. A plurality of samples of the early-late correlation difference are taken around the equilibrium point on the S-curve where the time error is zero. A recursive algorithm is used to compute the time adjustment necessary to time align the transmitter and the receiver by minimizing the squared estimation error.

Abstract: A receiver for optical signals arranged in packets of data having a discontinuous flow pre-reads the signal and generates, for each packet, a corresponding signal indicating the phase of the data in the packet, and a threshold level indicating the packet mean signal power. A delay line delays the discontinuous flow by a delay interval. A receiver responsive to the discontinuous flow delayed by the delay line performs, on each packet, a receiving operation on the basis of the threshold level and with a phase identified on the basis of the phase indicating signal.

Abstract: An apparatus including a sampling circuit to generate sampling clocks from a local clock and the sampling clocks to sample incoming data and a quarter clock, a phase detector to detect a phase difference between a data transition in sampled data and the local clock, and a delay line adapted to delay the sampled data by the detected phase difference.

Abstract: A recording medium includes transport stream units recorded therein, wherein the transport stream units are created by adding a transport time reference to each unit of a transport stream, and wherein the transport time reference includes two time fields of different time bases, a smaller-unit time field being reset when a count value reaches a predetermined value and a bigger-unit time field being incremented by 1 when said smaller-unit time field is reset, the count value corresponding to an arrival time of each unit of the transport stream.

Abstract: Apparatus and methods for determining an operational mode of a far-end modem are disclosed. Where the multimode modem is a call initiator, a method according to the invention includes transmitting a V.8 ANSam tone to the far-end modem, receiving a response signal from the far-end modem, and determining from the response signal whether the far-end modem is a commercial modem or a secure modem. Where the multimode modem is a call responder, a method according to the invention includes transmitting to the far-end modem a P1800 Hz tone with phase reversals, receiving a response signal from the far-end modem, and determining from the response signal whether the far-end modem is a commercial modem or a secure modem.

Abstract: A modem comprises circuitry for receiving an analog signal from a line and circuitry for converting the analog signal to a digital signal. The digital signal comprises a plurality of ideal sample points (P0-P3), each separated in time by a period T, and the plurality of ideal sample points comprises a sync sequence (14). The modem further comprises circuitry (34) for detecting the sequence comprising an integer number S of sampling circuits (38, 40), wherein S is two or greater. Each of the sampling circuits comprises circuitry for taking a sample corresponding to each of the plurality of ideal sample points at least once per the period T. Each of the sampling circuits also comprises circuitry for comparing a plurality of taken samples to a correlation sequence. Finally, each of the sampling circuits comprises circuitry for outputting a sync detected signal (SYNC0, SYNC1) in response to a sufficient match between the plurality of taken samples and the correlation sequence.

Abstract: Techniques for improved diversity pilot estimation in rapidly changing channel environments are disclosed. In one aspect, a difference estimate is updated when a current received symbol comprises a difference between the primary and diversity channels, and a sum estimate is updated when a current received symbol comprises a sum of the primary and diversity channels. The primary channel and the diversity channel are estimated in response to the sum estimate and the difference estimate. In another aspect, the sum estimate and difference estimate are produced by filtering the received symbols. In yet another aspect, received symbols are demodulated in response to the primary and diversity channel estimates. These aspects have the benefit of incorporating the most recently received symbol, resulting in more accurate channel estimates and hence improved demodulation performance, increased system capacity, lower required transmit power, and other benefits.

Abstract: A method and apparatus for achieving longer data transmission distances in Symmetrical Digital Subscriber Lines (SDSL) systems, while providing spectral compatibility with Asymmetrical Digital Subscriber Lines (ADSL) systems is disclosed. The method and apparatus enables deployment of SDSL and ADSL in any mix in a binder group of twisted pair copper wires without sacrificing performance of either system. The apparatus transmits signals from opposite ends of the twisted pair subscriber loop using first and second discrete frequency bands. The advantages include longer service reach and deployment without regard to ADSL/SDSL services mix in a binder group.

Abstract: Systems and methods are provided for identifying frequency offsets which may for example have been introduced after a signal has been transmitted over a wireless channel. The method involves sampling a received signal having an input bandwidth to generate a respective set of samples for each of a plurality of symbol periods; filtering the sets of samples using DWPT (discrete wavelet packet transform) filters to produce a plurality of sub-sampled outputs, the sub-sampled outputs each having a respective fraction of the input bandwidth; for each of the sub-sampled outputs, performing a narrowband FFT on the sub-sampled output produced over a plurality of symbol periods to generate a respective set of frequency domain samples; processing each set of frequency domain samples to determine at least one respective frequency offset.

Abstract: A method and apparatus for data transmission using existing highly compressed telecommunications media, and in particular encoding, transmitting, receiving, and decoding digital data using vocal sounds.

Abstract: A receiver circuit is for processing a received signal which includes at least a first portion and a second portion which repeats the content of the first portion after a repeat interval. For example, the receiver may be for DVB-T signals using COFDM. Two correlation values are measured. The first is between the first portion of the received signal, delayed by the repeat interval plus a difference interval, and the second portion. The second is between the first portion of the received signal, delayed by the repeat interval minus a difference interval, and the second portion. Any difference between the correlation values represents a difference between the receiver sampling rate, and the required sampling rate, and can be used to adjust the receiver sampling rate.

Abstract: A non-frequency-hopping node and a method for using such a node to transmit and receive data in a frequency-hopping system are disclosed. In one embodiment, a non-frequency-hopping node interacts with a frequency-hopping spread-spectrum (FHSS) system, which comprises a wireless medium or electromagnetic airwaves, a frequency-hopping node coupled to the wireless medium and an access point coupled to the wireless medium. The non-frequency-hopping node connects to the wireless medium and listens for an active signal generated by the FHSS system on a predetermined frequency channel. Upon detecting the active signal, the non-frequency-hopping node exchanges information with the FHSS system on the predetermined frequency channel.

Abstract: The present invention is directed to a method of selecting nodes in a multi-hop network having a combined coverage that reaches all the nodes in the network. These nodes called parent nodes, together with the root broadcast synchronization information regularly to the rest of the network. As part of the selection process, the parent nodes that would not interfere with each other are identified and then scheduled to broadcast synchronization information at the same time. Further, a time division structure can be used to control the access of these parent nodes to a common communication channel, resulting in the efficient use of the bandwidth available. The time division structure also ensures that each node receives regular synchronization information so that it can acquire and maintain synchronization with the root. However, other structures are also contemplated such as frequency division, code division and hybrids.