Abstract: Systems and methods automatically compensate for long-term drift of frequency standards or references used by transmitting and receiver terminals to avoid manual adjustment of the terminals to bring them back within operating tolerances and minimize communications outages caused by inability of the system to otherwise accommodate for such drift. The present invention may provide automatic band selection to maintain a modulated carrier within an operating range of an automatic frequency control or tracking capability of a communication device. This may be accomplished by selecting an appropriate reference signal used to control a center frequency of an automatic frequency control circuit (such as a PLL) or used to convert the carrier frequency of the modulated carrier to fall within the operating range of the automatic frequency control circuit and/or by causing the transmitting station to at least partially correct the frequency discrepancy.

Abstract: A differential phase detection device receives first through fourth detection signals from a photodetector and detects a differential phase signal therefrom, the differential phase detection device includes a slicer slicing and digitizing each of the detection signals with respect to a reference level. A synthesizer synthesizes the digitized detection signals and generates therefrom synthesis signals. A phase difference detector compares phases of the synthesis signals and outputs a first phase difference signal and a second phase difference signal. A matrix circuit processes the first and second phase difference signals to output the differential phase signal.

Abstract: A receiver includes an I-Q demodulator (135) responsive to the I and Q components carried on a first frequency signal line (132). A demodulator frequency generator (275) generates a demodulating signal to extract the carried I and Q components. A phase adjustment circuit (105) makes the demodulating signal substantially in phase with the first frequency signal. A transition detector (445) generates a state transition signal in response to a change of state of at least one of the I and Q signals. A peak detector (460) generates a peak detected signal in response to occurrence of a peak amplitude of at least one of the I and Q signals. A clock generator (470) adjusts the phase of a symbol clock signal used to decode the I and Q components in response to the state transition signal and peak detected signal.

Abstract: A data reproducing apparatus and method for improving data detection performance by adjusting decision levels used in a data detector. The data reproducing apparatus includes an equalizer which equalizes an input digital signal, a data detector which detects data from the output of the equalizer based on decision levels, and a level decision unit which detects levels corresponding to the decision levels used in the data detector from the output of the equalizer and feeds back corrected decision levels, which adaptively vary with the output level of the equalizer, to the data detector. Accordingly, the detection performance of the data detector is improved.

Abstract: A method of transmitting and rapidly recovering a burst of data without first having to establish a timing or phase lock. The signals are transmitted as modified Manchester coded signals having pulse transitions at a clocking pulse rate which is a multiple of the clocking pulse rate at which the signals are originally generated, and wherein the MOOSE coded signal is modified by ON-OFF keying.

Abstract: The pilot signal reception method of the present invention irregularly receives pilot symbols. That is, the pilot signal reception method performs irregular reception processing such as randomizing reception timings or changing reception timings according to reception situations as appropriate to reduce influences of fading. Randomization of reception timings is implemented by generating random timings using a random timing generation circuit.

Abstract: A phase and edge aligned local clock signal is generated in a data-receiving unit by deriving the local clock signal from a forwarded clock signal received from a transmitting unit. The local clock signal is a delayed replica of the forwarded clock signal, such that the receiving unit maintains synchronism between the local clock signal and the forwarded clock signal. Thus, transfers from an input latch to other components in the receiving unit can be effected in step with the receipt of data in the input latch.

Abstract: An apparatus comprising an analog circuit, a first digital circuit, and a second digital circuit. The analog circuit may be configured to generate a plurality of samples of an input signal in response to a plurality of phases of a reference clock. The first digital circuit may be configured to generate (i) one or more data signals, (ii) a first strobe signal, and (iii) a second strobe signal in response to the plurality of samples, the plurality of phases, and a correction signal. The second digital circuit may be configured to generate the correction signal and a width signal in response to (i) the one or more data signals, (ii) the first strobe signal, and (iii) the second strobe signal.

Abstract: Transmit parallel interfaces and methods are provided in which a clock signal is generated that maximizes the setup and hold window of input data. In at least some embodiments, a divider circuit provides a clock signal in one clock domain that has a rising edge located very close to the falling edge of a system clock in another clock domain.

Abstract: Managing assigned fingers in wireless telecommunication, such as Code Division Multiple Access (CDMA), using a finger lock mechanism. The method includes a series of steps, including a first step of receiving a finger assignment from a searcher portion of a communication device. Next, the signal-strength of the finger assignment is determined, and a time period over which the signal-strength exists is determined. The finger assignment is then compared to multiple signal-strength thresholds and to a time threshold. In the next step, the finger assignment is evaluated for a combing operation based upon which of the aforementioned thresholds it satiates. In particular, the finger assignment is enabled for a combining operation if it is a new finger assignment or if it continues to satiate a combine signal-strength threshold. Alternatively, the finger assignment is not enabled for combining but neither is it deassigned (e.g.

Abstract: An ADSL remote terminal end transceiver unit synchronizes transmission of upstream and downstream data between TCM-ISDN communication and ADSL communication, and in addition, provides NEXT tables (155, 157) and FEXT tables (154, 156), in which are stored equalizing coefficients appropriate for a NEXT noise and a FEXT noise generated when data travel upstream and downstream in TCM-ISDN communication, to equalizers TEQ (142) and FEQ (145) of the ADSL remote terminal end transceiver unit. As a consequence, even when the FEXT noise and the NEXT noise are generated one after another in TCM-ISDN communication, the TEQ (142) and the FEQ (145) can switch between the NEXT table and the FEXT table, achieving TEQ and FEQ characteristics which are most appropriate for the respective noises.

Abstract: A repeater system for receiving a modulated input signal and for transmitting a modulated output signal comprising a clock oscillator for providing a repeater system clock, a demodulator for demodulating an input signal and a modulator for modulating the demodulated signal to obtain a modulated signal. The demodulator comprises a first mixer, a first controllable oscillator and a feedback circuit, the first controllable oscillator being controlled by a first control value such that the frequency of the demodulated signal approaches a desired value. The modulator comprises a second mixer and a second controllable oscillator, the second controllable oscillator being controlled by a second control value such that the modulated output signal has a predetermined output frequency. A controller derives the second control value.

Abstract: A low power DSL modem transmitter, suitable for incorporation in integrated DSLAM server line cards, transmits full power physical frames which include a control channel and a data field when data is available for transmission and physical frames having only a control channel or a control channel and a low power synchronization field when data is not available for transmission. And a method for controlling the total power dissipated in the integrated DSLAM by selectively restricting the flow of data packets to the DSLs.

Abstract: A base station transmitter having a digital predistorter and predistortion method is disclosed. The predistortion is accomplished by delaying a digital input signal, predistorted by a predistortion unit, for a predetermined time. A coefficient of a non-linear characteristic model of a power amplifier is generated using a digital output signal, converted from an amplified output signal of the power amplifier, and the delayed digital input signal. A reference signal is randomly generated to produce a predistortion model having a characteristic opposite to the non-linear characteristic of the power amplifier. A predistortion error function is extracted by subtracting the reference signal and the non-linear characteristic model of the power amplifier, after the produced coefficient is applied to the model. A coefficient of the predistortion unit is controlled adaptively using the predistortion error function.

Abstract: A frequency interleaving circuit frequency-interleaves main signals generated according to sound data by parameters set according to frequencies of transmission channels. A sub-signal generating circuit generates sub-signals for transmission control including pilot signals. Mapping circuits modulate the sub-signals by using pseudo-random sequences generated based on initial values of random codes set according to frequencies of transmission channels. The frequency-interleaved main signals and the sub-signals modulated by the mapping circuits are OFDM-modulated. Then, they are converted to the frequencies of the transmission channels. An increase of a dynamic range of transmission signals can be suppressed by controlling the initial values of random codes set.

Abstract: A phase comparator (106) compares a phase of the output signal of the quadrature modulator (104) with the phase of the signal obtained by frequency-converting the output signal of a first VCO (101) via the second VCO (102) and the first mixer (108). A PLL modulator includes a low-pass filter (107) filters a component below a predetermined frequency of the output signal of the phase comparator (106) and supplying the resulting signal to the frequency control terminal of the first VCO (101). The output signal (TS1) of the first VCO (101) is a modulated signal conforming to a modulation system having a constant envelope waveform, while the output signal of the quadrature modulator (104) is input to the first band-pass filter (110) and the output signal (TS2) of the first band-pass filter is a modulated signal conforming to a modulation system accompanied by an amplitude component as information.

Abstract: A method and system are provided for recognizing a path having low level signals, which is conventionally treated as useless, as a valid receiving path. Recognition is made from a plurality of receiving paths in a CDMA wireless telecommunication system by receiving at least one set of signals through a transmission path, generating at least two spread codes each with its own delay time, and calculating at least two correlation values of the set of signals with the spread codes. A CDMA wireless telecommunication mobile station is also provided for receiving a set of telecommunication signals through a telecommunication path from a base station. At least two spread codes are generated, each with its own delay time and a predetermined number of spread code bits. At least two correlation values of the set of signals are calculated with the spread codes.

Abstract: A method for communicating serial input data over a transmission link. Serial input data is partitioned into parallel data elements and is coded prior to rotation by an invertible linear mapping. Resulting frames of parallel sign elements are transmitted over the link. After receipt from the link, the signal is assembled into frames of parallel signal elements which are de-rotated by an inverse linear mapping, then decoded. Thresholding the result of the inverse mapping recovers the parallel data elements, which are then re-assembled into serial output data. The linear mapping employs: 1) commuting rotation matrices for convolutionally rotating data vectors into signal vectors and vice-versa; 2) filter bank polyphase rotation matrices; or 3) computationally efficient multi-rate wavelet filter banks. Coefficients of the rotation matrix of the receiver are adaptively equalized to correct for transmission path distortion.

Abstract: A rake receiver tracks a component of a multipath information signal transmitted over a communication network. The rake receiver aligns and synchronized the component with a locally generated replica of the code sequence that was originally used to spread the information signal at the transmitter side. The rake receiver derives an early de-spread signal using an early shifted version of the replica of the code sequence. The replica is early shifted by a variable delay. The rake receiver also derives a late shifted de-spread signal using a late shifted version of the replica of the code sequence. The replica is late shifted by the same variable delay. The variable delay may be chosen arbitrarily or among a selection of predetermined values. The predetermined values may be selected so that the tracking process is optimized.

Abstract: Providing a high-speed data service and voice service in a transmission system employing two binary, one quarternary (2B1Q) modulation/demodulation, using a high-speed data service remote terminal, a plurality of user data service and voice service terminals, and a multi-rate digital subscriber line (MDSL) terminal connected to the remote terminal through a twisted pair line, and to the user terminals. During downstream voice service, the remote terminal assembles and transmits an high bit rate digital subscriber line (HDSL) frame by including signaling signals for the voice service and signal processing mode information in a user-defined interval of the high bit rate digital subscriber line frame, to the multi-rate digital subscriber line terminal through the twisted pair line. During upstream voice service, the remote terminal receives the high bit rate digital subscriber line frame and transmits the signaling signals received to an exchange.