Abstract: Methods and systems for processing a single sub-channel that includes two or more combined channels. Using intermediate frequency sub-sampling, two or more channels from a broad band signal are combined into a single sub-channel for further analog and digital processing. Each of the two or more channels is down converted to an intermediate frequency, filtered to remove certain undesired channels, and combined such that the two or more channels are adjacent to each other. A digital representation of the sub-channel is produced from the combined intermediate frequency channels. Each channel within the digital representation is down converted to baseband, and the in-phase and quadrature components are separated from each other. Compared to one direct down conversion technique, intermediate frequency sub-sampling as described in the application may reduce the number of analog to digital converters and control amplifiers used in analog processing by a factor of four.

Abstract: A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal. The method may involve obtaining a sample of the composite QPSK signal; separating the individual codes from the composite QPSK signal; analyzing the individual codes against corresponding commanded code power settings for the individual codes; and determining a code power correction signal needed for each of the individual codes needed to adjust a code power for each of the individual codes to match their corresponding commanded code power settings.

Abstract: A method and system are provided in a wireless communications system comprising a plurality of nodes (users) working cooperatively. The system provides cooperative diversity by allowing nodes to actively share their antennas and other resources to obtain spatial diversity. The nodes receive the same message (information data) from a common source. Each node enhances the reliability of the message with a modern forward error correction (FEC) code, converts the FEC encoded message into an ensemble of symbols, divides the ensemble of symbols into packets, modulates, dithers and transmits the packets to a receiving node. The dithering process is performed by varying the signal amplitude, phase, frequency and/or symbol timing of the modulated packets. A unique dither pattern is assigned to each node. The receiving node captures a composite signal comprising the transmitted packets of all or most of the transmitting nodes in the cooperative communications system.

Abstract: Systems for audio and data transmission in a broadcast band are disclosed. The system comprises a channel condition assessment module at the transmit side to identify an un-occupied or empty channel to transmit. The system also comprises a means to achieve automatic channel coordination between the transmit side and the receive side. Further, the transmit side includes a digital interface module and the receive side includes a digital output interface module configured to control an embedding electronic device. Means for enhancing audio privacy and digital data rate are also disclosed.

Abstract: A communication channel has a highly linear switched current mixer that incorporates passive filtering (e.g., low pass, notch) for improved transmitting (Tx) and receiving (Rx) with adding external filtering components. A high IIP2 (input referenced second order intercept point) of the receiver at the Tx offset is essential to avoid corrupting the system's sensitivity performance, and a high triple beat (TB) is required to avoid sensitivity degradation due to transmitter leakage. Thanks to the embedded filtering in the mixer and the active post-distortion (APD) method in a low noise amplifier (LNA), the required high linearity is achieved with low noise figure and power consumption, overcoming transmitter power leakage without the use of a SAW (surface acoustic wave) filter.

Abstract: Methods and systems using a Gray-like labeled QAM cross-constellation are disclosed. In some embodiments a Gray-like labeled QAM cross-constellation is used in wireless communication systems.

Abstract: A method for transmitting data in the form of pulse sequences, including a signal synchronization step carried out by a receiver of dataframes DF, in the course of which at least one time window ?T(0) is scanned in search of the beginning PSB of a pulse sequence. The time window is then subdivided into a predefined number of sub-windows ?T(1). The sub-windows are then scanned during further signal detection steps until the beginning PSB of the pulse sequence has been detected within one of the sub-windows which will then be substituted for the previous time window AT(0), until the width of the resulting sub-windows becomes smaller than a predetermined minimum width.

Abstract: An interleaver and scheme for interleaving in which highly correlated bits are maximally separated. The scheme involves interleaving a set of bits to be delivered to a modulation system that utilizes a quantity of N carrier frequencies. A first block of N consecutive bits is assigned to each of N bins, on a one-bit-per-one-bin basis. The aforementioned assignment proceeds in a particular sequence. A second block of N consecutive bits is assigned to each of the N bins, on a one-bit-per-one-bin basis. The second block is assigned in the same sequence the first block was assigned. The second block is consecutive to the first block.

Abstract: The present invention relates to a system for communicating between two integrated circuits (ICs) or within an IC. The ICs are either on the same circuit boards or on different circuit boards with a common backplane. The system comprises a first integrated circuit having an output circuit for generating phase shift keying signals and a second integrated circuit having an input circuit for decoding the phase shift keying signals. The output circuit may include a ring oscillator for generating multiple clock signals that are phase-locked to one another.

Abstract: A wireless data transfer system. The system includes a first hard disk, a first hard disk interface, and a first transmitter. The first hard disk interface is configured to retrieve first read data from the first hard disk and to create a first bit serial signal from the retrieved first read data. The first bit serial signal conforms to a protocol selected from the group consisting of serial advanced technology attachment (SATA) protocol and serial attached small computer system interface (SAS) protocol. The first transmitter is configured to operate at selected carrier frequency greater than 50 GHz, comprising, to operate at effective isotropic radiated power level less than or equal to 40 dBm, to receive the first bit serial signal from the first hard disk interface, to modulate the first bit serial signal using amplitude shift keying modulation to substantially create directly a first signal, and to transmit the first signal.

Abstract: A method and apparatus for high quality signal transmission, which utilizes normal-mode current flow and produces an audio output signal with suppression of normal-mode voltage amplitude, comprising transmitting an audio input signal source though (1) a buffer amplifier; (2) a modulated current source; (3) a pair of wires; (4) a current transformer; and (5) a receiver amplifier for said current transformer.

Abstract: A method and system to generate decoded information from received symbols in communication receivers. A first embodiment is a method to detect digitally modulated symbols and generate decoded information. The method includes receiving digitally modulated symbols, demapping the digitally modulated symbols to generate soft decisions representing digitally modulated symbols, multiplying the soft decisions by an adaptive factor to generate scaled soft decisions; and decoding the scaled soft decisions to generate decoded information. A second embodiment is a system having modules to detect digitally modulated symbols and generate decoded information. These embodiments can be applied in several wired and wireless communication applications including, but not limited to, WiMAX applications.

Abstract: An apparatus for determining and/or monitoring a physical or chemical process variable of a medium, having a sensor unit, which produces a measurement signal with a piece of process variable-dependent, basic information, and having an evaluation unit which, from the measurement signal of the sensor unit, determines a measured value for the process variable, and which produces an output signal with information concerning whether the measured value is greater or smaller than a limit value. A first and second modulation range are provided, and the evaluation unit modulates the output signal within the first or second modulation range with the basic information of the measurement signal, with the evaluation unit modulating the output signal within the first modulation range when the process variable is smaller than the limit value, and with the evaluation unit modulating the output signal within the second modulation range when the process variable is greater than the limit value.

Abstract: A method and apparatus to improve modulation efficiency. A symbol is created in which the relative position of a second pulse is a symbol period encode at least one bit. The symbol is transmitted across a communication channel. The one or more bits modulated by the position of the second pulse are recovered such that high bit rate communication may occur without channel compensation.

Abstract: The present invention relates to a transceiver for bidirectional frequency division multiplexed transmission, a communication system including one or more transceivers. Optionally, the communication system is a communication system for a digital subscriber line. The transceiver comprises transmission means with a voltage source output or a current source output for transmitting data in a transmission frequency range, receiving means for receiving data in a receiving frequency range, and a coupling impedance for connecting the transmission means and the receiving means to a transmission medium. The magnitude of the coupling impedance in the transmission frequency range is smaller than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a voltage source output and is higher than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a current source output.

Abstract: Apparatuses and methods for receiving an amplitude modulated signal in one of two modes depending on the quality of the received signal. In a first mode, the amplitude modulated signal is converted directly to a baseband signal. In a second mode, the amplitude modulated signal is converted to an intermediate frequency signal. The present invention advantageously combines direct conversion and image-rejection heterodyne receiver topologies with a relatively large degree of component reuse and relatively few additional components.

Abstract: Systems and methods for performing vibration error suppression in a fiber optic gyro sensor. An example system includes a light source, a sensing loop assembly, a photo detector, and a processing component. The light source generates a light signal that is then modulated by the sensing loop assembly and applied to a fiber optic coil in the assembly. The photo detector receives a modulated light signal that is an output of the sensing loop assembly (coil) and generates an analog signal. The processing component converts the generated analog signal into a modulated digital signal, determines an average of the modulated digital signal, determines an intensity modulation amplitude based on the determined average of the modulated digital signal, and re-scales the modulated digital phase signal based on the determined intensity modulation amplitude.

Abstract: A first signal generation section 11 generates a baseband modulation signal for an ASK modulation scheme from transmission data. A second signal generation section 12 generates a pair of baseband modulation signals for a non-ASK modulation scheme from transmission data. When performing non-ASK modulation, a switch 15 connects between an input terminal d and an output terminal and outputs the baseband modulation signals based on the non-ASK modulation. When performing ASK modulation such that the transmission power ratio of the ASK modulation scheme to the non-ASK modulation scheme is a factor of 1, a switch 14 connects between an input terminal b and an output terminal and the switch 15 connects between an input terminal c and the output terminal. When performing ASK modulation such that the transmission power ratio is a factor of 2, the switch 14 connects between an input terminal a and the output terminal and the switch 15 connects between the input terminal c and the output terminal.

Abstract: Aspects of a method and system for digital to analog conversion for power amplifier driver amplitude modulation are presented. Various aspects of the system may include circuitry that enables oversampling, within a single integrated circuit device, of each of a plurality of samples in a digital baseband signal. The circuitry may enable reduction of a number of bits, i.e., coarse quantization, in each of the oversampled plurality of samples so as to cause displacement of the quantization noise that occurred as a result of the coarse quantization. A subsequent signal may be generated based on the oversampled signal. The circuitry may enable the subsequent signal to be low-pass filtered utilizing filter circuitry in the single integrated circuit device, thereby attenuating the quantization noise displaced into the higher frequency range of the oversampled signal.

Abstract: A remote transmitter system for vehicle applications includes a remote transmitter for carrying by a user and a receiver for mounting on a vehicle and receiving an amplitude modulated signal. The transmitter is operative to transmit the amplitude modulated signal at a plurality of different carrier frequencies. The receiver is programmed to select the carrier frequency for reception by detecting noise due to unwanted frequency modulated signals based on a received signal strength indicator, and detecting noise due to unwanted amplitude modulated signals based on a data decoder. The receiver changes the selected carrier frequency when either noise becomes excessive.

Abstract: A method and apparatus for wireless data transmission between a base station and one or more, in particular, passive and/or backscatter-based transponders, in which the base station modulates a carrier signal with a modulation signal, to generate synchronization markers, and transmits the modulated carrier signal. Whereby, a frequency of the modulated carrier signal can be switched between different frequency values.

Abstract: An ASK communication device includes a master station and slave stations connected to the master station through a bus line. The master station includes a transmission unit for ASK-modulating a carrier signal outputted from an oscillation circuit owned thereby and outputting, to a bus line, ID signals of the respective stations and data transmitted to the respective slave stations in a case of transmitting the data from the master station, and outputting the ID signal of the slave station as a transmission source and the carrier signal to the bus line in a case of transmitting the data from the slave station, and a master-side reception unit for receiving, through the bus line, the data transmitted from the slave station. The at least one slave station includes a slave-side reception unit for receiving the data transmitted from the master station and other slave stations, and an attenuation unit for attenuating and ASK-modulating the carrier signal outputted from the master station to the bus line.

Abstract: The present invention relates in general to a method, apparatus, and article of manufacture for providing high-speed digital communications through a communications channel. In one aspect, the present invention employs adaptive or adjustable equalization circuitry and techniques in the transmitter and/or receiver to enhance the system performance of, for example, a system using the PAM-4 coding.

Abstract: A timing recovery method is presented which enables time recovery of multi-level PAM signals at baud rate. The method uses a fixed A/D clock, a digital interpolator to re-synchronize incoming samples; a timing phase detector; a loop filter and a numerically controlled oscillator (NCO), controlling re-synchronization of incoming samples within the interpolator. The usage of a Farrow interpolator and a multi-level PAM timing phase detector allows a reduced complexity of the time recovery circuit and a free running clock to the A/D converter.

Abstract: An AM compatible digital audio broadcasting signal comprises an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, and a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions. Time diversity can be included between the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals, and/or between groups of the digitally modulated subcarrier signals. A broadcasting method, and transmitters and receivers and that utilize the signal are also provided.

Abstract: A method for detecting encoded digital data from a substantially sinusoidal waveform, the encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?, the detection including deriving sync pulses from minima and maxima of the substantially sinusoidal waveform to frame data words.

Abstract: A rearview assembly includes a mounting structure for attaching to a vehicle. The mounting structure includes a housing that has a rearview element disposed inside for providing a driver of the vehicle with a view to the rear of the vehicle. The rearview assembly also includes a continuously variable slope delta encoder module in or on the mounting structure configured to generate a feedback signal. The rearview assembly also includes a pre-processing module on or within the mounting structure. The pre-processing module is configured to process a source signal and the feedback signal from the continuously variable slope delta encoder module, and to provide a pre-processed signal to the continuously variable slope delta encoder module based on the value of the source signal and the feedback signal.

Abstract: A method and associated apparatus for preserving frequency spectrum in a linear modulation scheme, by adding a compensation signal to a modulated signal, the compensation signal having the same spectrum as the modulated signal. In the present invention, peaks above a pre-determined maximum threshold and/or minima below a pre-determined minimum threshold are searched. When a peak is found, the amount by which the signal peak exceeds the maximum threshold, as well as the signal phase at the peak is calculated. A compensation signal is generated with the same peak amplitude as the signal exceeds the maximum threshold, and with opposite phase. Then the shape of the compensation signal is chosen to be the same as the transmitter pulse of the modulated signal. Finally, the compensation signal is added to the modulated signal.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of data regions, the first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the data regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function different from Y=sin ? at phase angles lying inside the data regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded. The third harmonic of the waveform may be generated and used.

Abstract: A technique for receiving differential multi-PAM signals is disclosed. In one particular exemplary embodiment, the technique may be realized as a differential multi-PAM extractor circuit. In this particular exemplary embodiment, the differential multi-PAM extractor circuit comprises an upper LSB sampler circuit configured to receive a differential multi-PAM input signal and a first differential reference signal, and to generate a first differential sampled output signal. The differential multi-PAM extractor circuit also comprises a lower LSB sampler circuit configured to receive the differential multi-PAM input signal and a second differential reference signal, and to generate a second differential sampled output signal.

Abstract: An electrical circuit to add and subtract differential input signals may be implemented using distributed differential transmission lines having a length substantially equal to one quarter of a wavelength of the differential input signals according to an effective electrical permeability of the transmission line. Alternatively, the electrical circuit may be implemented with lumped reactive elements.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles ?n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range ?? beginning at each phase angle ?n, said first function being Y=sin ?; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of ?? beginning at each phase angle ?n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of ?? associated with each phase angle ?n where data of the second value is to be encoded, the second function being different from Y=sin ?.

Abstract: A polar modulator contains a phase locked loop which is designed to emit a radio-frequency signal at one frequency to one output, with the frequency being derived from the reference signal and from a phase modulation signal at a control input of the phase locked loop. The modulator additionally has a second signal input for supplying an amplitude modulation signal. The second signal input is connected to a control input of a pulse width modulator, one of whose signal inputs is coupled to the output of the phase locked loop. The pulse width modulator is designed to vary the duty ratio of a signal which is applied to the signal input, with this variation being adjustable via a regulation signal at the control input. A filter can be connected downstream from the output of the pulse width modulator and suppresses higher harmonic components in a signal which can be tapped off at the output of the pulse width modulator.

Abstract: In a transponder (1) and an integrated circuit (5), the integrated circuit (5) has two circuit sections (18, 19) that are arranged for supply with two supply voltages of different levels (VL-HV, VL-LV), a first rectifier circuit (20) and a limiter stage (21) connected downstream of the first rectifier circuit (20) being provided, from which limiter stage (21) the higher, first supply voltage (VL-HV) for the first circuit section (18) can be picked off, and a second rectifier circuit (23) and a control stage (24) to control said second rectifier circuit (23) being provided, from which second rectifier circuit (23) the lower, second supply voltage (VL-LV) for the second circuit section (19) can be picked off without passing through an intervening limiter stage.

Abstract: To reduce the size, weight and cost of an interrogator which is included in an RFID system and required to have a high output power, the interrogator for transmitting a signal shares a radio wave source or a power supply with a portable wireless terminal such as a mobile phone or a portable communication device. For this purpose, a radio frequency transmitter signal is subjected to amplitude modulation by information to be transmitted to a transponder. Furthermore, part of the radio frequency transmitter signal extracted using a coupler is used to perform synchronous detection on a radio frequency receiver signal returned from the transponder, and data coming from the transponder are extracted.

Abstract: A multivalued FSK modulation system is provided in which when data to be transmitted is multivalued and transmitted/received, the detection level is different every symbol. When a two-valued signal is transmitted as one symbol, data (11), (01), (00) and (10) are previously set to be, for example, a shift of ?6, a shift of +6, a shift of +2, and a shift of ?2, respectively. When data to be input next is (00), mapping is performed so as to provide a sign weight of +2 from the sign weight at the position of current data. When the data to be input next is (10), mapping is performed so as to provide a sign weight of ?2 from the position of the current sign weight. Thus, even if data of the same level is input, signals can be always detected in different levels, so that the sign detection point is not specified erroneously.

Abstract: A method, apparatus and system relate to detecting an interfering device in a wireless network such as a wireless local area network (WLAN). In wireless networks using orthogonal frequency division multiplexing (OFDM) and adaptive bit loading (ABL), adaptive modulation information should be somewhat symmetric in uplink and downlink directions. By comparing modulation adaptations in the uplink and downlink directions of a communication channel between at least two terminals, identified differences can indicate the presence of a potential interferer in the wireless network. A location of the potential interferer can be estimated if a location of one or more network terminals experiencing interference is known or can be determined. An exemplary implementation for a device of the invention may be as an Access Point (AP) in the WLAN.

Abstract: A method for reducing out-of-band emission in an AM transmitter for digital transmission includes generating, from a digital modulation signal, an amplitude signal and a phase-modulated radio frequency signal configured to control the AM transmitter. A digital modulation process is used in which a hole is formed around a 0/0 point so that a zero crossing is avoided by a substantial margin in a vector diagram representation. Thereby a respective bandwidth of the amplitude signal and the phase-modulated radio frequency signal is limited so that the out-of-band emission decreases as a function of a shoulder distance achievable by the AM transmitter at a rate where a spectrum mask is not exceeded.

Abstract: A digital communication system (20) in which a signal constellation (30) of a dimensionality of at least four is used, with distance properties chosen to reduce the bit error rate compared to that of digital communication systems using signal constellations of half the dimensionality. A symbol generator (21) uses the higher dimensional signal constellation (30), or any orthogonal transformation of the higher dimensional signal constellation (30), to translate a bit stream into a stream of higher dimensional symbols, which it then provides to a modulator (22). The modulator (22) transmits each higher dimensional symbol in at least two parts, using a modulation scheme according to the prior art, such as QAM or QPSK.

Abstract: Program data is provided in association with a main audio program to a receiver of a duplicative radio broadcasting system wherein a duplicative broadcast (such as a hybrid IBOC broadcast) includes a primary channel and a backup channel in a predetermined frequency allocation. Both the primary channel and the backup channel transmit the main audio program, and the primary channel transmits program data not included in the backup channel. The receiver includes an audio output for reproducing the main audio program and a display for displaying the program data. The method includes recurrently compiling a program event list of the program data corresponding to a current program event and a plurality of upcoming program events. The program event list is recurrently transmitted within the primary channel. The receiver recurrently recovers the program event list and stores the program data in a memory. The program data of the current program event is displayed.

Abstract: An I/Q demodulator optimized with a minimum amount of hardware. First and second multiplexers generate I and Q signals with respect to an input data signal; and first and second 2-decimation units decimate the I and Q signals generated by the first and second multiplexers, to output effective I and Q signals. A filtering unit filters the effective I and Q signals. As a result, a size of the hardware is reduced, and an operation frequency of the filter is reduced.

Abstract: A vehicle mounted DSRC apparatus is capable of achieving reduction in the size and cost thereof. The vehicle mounted DSRC apparatus includes an ASK data generation part 11, an I data generation part 21, a Q data generation part 22, a first band limiting filter 23A for band limiting I data and ASK data, a second band limiting filter 24 for band limiting Q data, an ASK low pass filter 12A for removing harmonic components from the ASK data, first and second low pass filters 25, 26 for removing harmonic components from QPSK data, an ASK modulator 13 for ASK modulating the ASK data, a QPSK modulator 27 for QPSK modulating the QPSK data, and a power amplifier 30 for amplifying output data of the ASK modulator 13 or the QPSK modulator 27 to a desired level thereby to output it to an antenna as an ASK modulated signal and a QPSK modulated signal.

Abstract: In one embodiment, an MLD scheme for a wireless data communication system including steps (a)–(f). Step (a) includes calculating a first vector length for each of a plurality of complex vectors corresponding to a constellation having a plurality of combinations of possible data values. Step (b) includes selecting a subset of the combinations based on the first vector lengths calculated in step (a). Step (c) includes calculating, for a first transmitter, a second vector length for each complex vector corresponding to a combination in the subset. If there are one or more other transmitters, then, for each other transmitter, the method includes implementing steps (d) and (e). Step (d) includes reducing the subset based on the second vector lengths calculated in step (c). Step (e) includes calculating, for a current transmitter, a second vector length for each complex vector corresponding to a combination in the reduced subset.

Abstract: A delay locked loop circuit (200) in which multiple outputs are produced. A single delay line (24) is shared among multiple tap selection circuits (256A, 265B, 265C). Fixed phase shifts (412) can be introduced between multiple outputs. A modulating signal can be used in the tap selection processing to produce digital amplitude, frequency and/or phase modulation.

Abstract: An orthogonally-multiplexed orthogonally-amplitude-modulated (OMOAM) method is disclosed. The OMOAM signal is constituted by orthogonally multiplexing M component signals, each constructed by a data-chosen group of L orthogonal pulse-amplitude-modulated basis signals. A generalized signal model is proposed to characterize the OMOAM signal in a unified way such that the generalized signal model contains a multitude of new modulations. A generalized optimum receiver for coherently demodulating OMOAM signals is developed and analyzed in terms of the bit error probability for the additive white Gaussian noise channel. The spectral characteristics of the OMOAM signals constructed from various time-limited and band-limited basis sets are studied in terms of the fractional out-of-band power containment. Several general trends of error and spectral performance characteristics are exploited.

Abstract: Signalling information is conveyed from a transmitting device (101) to a receiving device (102) in a cellular radio network where user data transmission takes place on a traffic channel in discrete transmission bursts (111-120; 211-220; 310-313) consisting of consecutive symbols. A piece of signalling information is formatted into symbols which are transmitted as a block of consecutive symbols (FACCH) in a certain transmission burst of a traffic channel. It is also indicated within said certain transmission burst that it contains symbols carrying signalling information.