252results about "Pulse combined modulation" patented technology

A DC-DC converter includes a variable frequency oscillator, a control system and a power train. The DC-DC converter is well suited for use in a cell phone. The control system uses the output of the oscillator to control the power train. The oscillator varies its frequency as a function of a pseudo random number generator, thereby reducing electromagnetic interference caused by ripple in the output of the DC-DC converter.

[Problems] To realize a reliable and stable transfer of digital data that does not require a reference clock and a handshake operation. [Means for Solving the Problem] The present invention provides a digital data transfer method for alternately and periodically transferring first information and second information respectively in a first period and in a second period, wherein: an amount of information of the first information per unit time in the first period is greater than an amount of information of the second information per unit time in the second period; and the second information in the first period is transferred as pulse-width-modulated serial data.

[Problems] To realize a reliable and stable transfer of digital data that does not require a reference clock and a handshake operation.[Means for Solving the Problem] The present invention provides a digital data transfer method for alternately and periodically transferring first information and second information respectively in a first period and in a second period, wherein: an amount of information of the first information per unit time in the first period is greater than an amount of information of the second information per unit time in the second period; and the second information in the first period is transferred as pulse-width-modulated serial data.

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200, 1800, 2800) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Distortion introduced by an analog-to-digital converter (304) may be compensated using a variety of adaptive techniques. Linear distortion is compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A method for multiplexing communication resources to multiple users in a communication system having no network resource planning. The method includes the steps of: generating a generic time-frequency (T-F) mapping pattern (TFPgeneric), generating a set of orthogonal T-F mapping patterns from said generic T-F mapping pattern (TFPgeneric), performing a random variable cyclic offsetting of said set of orthogonal T-F mapping patterns in each transmission time interval (TTI), and allocating the orthogonal T-F mapping patterns to the one or more users and / or traffic channels in each TTI. A transmitter for executing said multiplexing method, and a system including such transmitters, are also disclosed.

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200, 1800, 2800) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Distortion introduced by an analog-to-digital converter (304) may be compensated using a variety of adaptive techniques. Linear distortion is compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A test apparatus includes digital modulators provided in increments of multiple channels. A baseband signal generator performs retiming of data input as a modulation signal for the in-phase (quadrature) component, using a timing signal the timing of which can be adjusted, thereby generating a baseband signal. A driver generates a multi-value digital signal having a level that corresponds to the baseband signal output from the baseband signal generator. A multiplier amplitude-modulates a carrier signal with the multi-value digital signal. An adder sums the output signals of the multipliers.

A method for detecting and quantifying impairments of a received communication signal of a QAM data communication system represented by a plurality of ideal values. The method includes storing a statistically significant number of a plurality of received points of the signal for each ideal value corresponding to a plurality of groups of said plurality of ideal values. The received points are defined by an in-phase and a quadrature components in a coordinate system in which a first axis is the in-phase axis and a second axis is a quadrature axis. The components have corresponding ideal components from their respective ideal value. Each group corresponds to respective impairments and is specific to the same.

A magnetic field communication method is provided for managing node with low power consumption which enhances performance and efficiency of a magnetic field area network in the low frequency region. The magnetic field communication method for managing node with low power consumption of the present invention is accomplished in a low-frequency wireless network that is comprised of a MFAN-C and at least one MFAN-N wherein a physical layer is comprised of a preamble, a header, and a payload, and the preamble is comprised of a wake-up sequence and a synchronization sequence. The wake-up sequence is only added to the preamble of the frame that is transmitted from the MFAN-C when the MFAN-N is being activated from the hibernation mode. The wake-up sequence is modulated using ASK modulation, and the synchronization sequence is modulated using BPSK modulation.

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Linear distortion is first compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200, 1800) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Distortion introduced by an analog-to-digital converter (304) may be compensated using a variety of adaptive techniques. Linear distortion is compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A communication system that uses keyed modulation to encode fixed frequency communications on a variable frequency power transmission signal in which a single communication bit is represented by a plurality of modulations. To provide a fixed communication rate, the number of modulations associated with each bit is dynamic varying as a function of the ratio of the communication frequency to the carrier signal frequency. In one embodiment, the present invention provides dynamic phase-shift-keyed modulation in which communications are generated by toggling a load at a rate that is a fraction of the power transfer frequency. In another embodiment, the present invention provides communication by toggling a load in the communication transmitter at a rate that is phase locked and at a harmonic of the power transfer frequency. In yet another embodiment, the present invention provides frequency-shift-keyed modulation, including, for example, modulation at one of two different frequencies.

In an adaptive modulation and coding method one or more adjustable values are created (S1), each corresponding to at least one of a plurality of available modulation and coding levels applicable to a signal transmitted from a transmitter to a receiver, and each representing a change to the level(s) to which it corresponds. One or more of said adjustable values is / are adjusted in dependence upon whether or not the signal is received successfully by the receiver (S2-S5). One of said available modulation and coding levels is selected (S6-S8) to apply to the signal based on such an adjustable value. Such a method can enable the appropriate modulation and coding level to be selected even when the path and channel conditions vary. The method is applicable to selecting modulation and coding levels in a high-speed downlink packet access system of a wireless communication network.

A spectral notch modulation technique for encoding information in a signal involves transforming the signal into the frequency domain via a fast Fourier transform (FFT) of length N, such that the signal is represented by N frequency bins, selectively nulling M of the N frequency bins, where nulled combinations of M frequency bins respectively correspond to encoded information bits, transforming the selectively nulled signal to the time domain via an inverse FFT, and transmitting the selectively nulled signal. At the receiving end, the signal is demodulated to recover the encoded information by transforming the signal into the frequency domain via a fast Fourier transform (FFT) of length N, identifying the set of M nulled frequency bins among the N frequency bins, and converting the set of M nulled frequency bins to corresponding information bits.

A new class of 16-ary Amplitude and Phase Shift Keying (APSK) coded modulations, called double-ring APSK modulation, based on an amplitude and phase shift keying constellation in which the locations of the digital signals to be encoded are placed on two concentric rings of equally spaced signal points. The APSK constellation parameters are optimised so as to pre-compensate the impact of non-linearities. The new modulation scheme is suited for being used with different coding schemes. It is shown that, for the same coding scheme, pre-distorted double-ring APSK modulation significantly outperforms classical 16-QAM and 16-PSK over a typical satellite channel, due to its intrinsic robustness against the high power amplifier non-linear characteristics. The proposed coded modulation scheme is shown to provide a considerable performance advantage for future satellite multi-media and broadcasting systems.

A communication system that uses keyed modulation to encode fixed frequency communications on a variable frequency power transmission signal in which a single communication bit is represented by a plurality of modulations. To provide a fixed communication rate, the number of modulations associated with each bit is dynamic varying as a function of the ratio of the communication frequency to the carrier signal frequency. In one embodiment, the present invention provides dynamic phase-shift-keyed modulation in which communications are generated by toggling a load at a rate that is a fraction of the power transfer frequency. In another embodiment, the present invention provides communication by toggling a load in the communication transmitter at a rate that is phase locked and at a harmonic of the power transfer frequency. In yet another embodiment, the present invention provides frequency-shift-keyed modulation, including, for example, modulation at one of two different frequencies.

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Linear distortion is first compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A method and apparatus is diclosed herein for performing distributed space-time coding. In one embodiment, the distributed space-time coding is used for downlink communications in wireless radio networks. In one embodiment, the method comprises storing information-bearing sequence at two or more base stations in a group of base stations; and transmitting data coprresponding to the information-bearing sequence from a number of base stations for receipt by a reciever of a user, where the number of base stations is not globally known a priori and indicates a diversity of order, such that the diversity of order M is obtained if a total of M number of antennas spread over multiple base stations transmit the information-bearing sequence, where M is an integer.

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. Because the transmitted packets are dithered independently in phase and / or amplitude, spatial diversity is transformed into temporal diversity.

A method and apparatus for frequency modulating a PWM involves 1) generating a high frequency carrier signal much greater in frequency than the PWM signal; 2) modulating the high frequency signal to generate a spread spectrum carrier signal; and, 3) retiming a PWM signal with this high frequency SS carrier signal so that the binary transitions of the PWM signal are aligned with the frequency varying carrier signal. In another embodiment, a PWM oscillator is driven by a second, FM oscillator having spread spectrum characteristics. In another embodiment a PWM oscillator is driven and modulated by a counter / frequency divider comprised of modules.

A digital polar transmitter includes a baseband processor configured to receive an input signal and to convert the input signal into a baseband amplitude component and a baseband phase component. The transmitter also includes a phase modulator in communication with the baseband processor. The phase modulator is configured to modulate an RF carrier signal based on the phase component and to generate a phase-modulated RF carrier signal. A power amplifier is provided in communication with the baseband processor and the phase modulator. The power amplifier is configured to amplify the phase-modulated RF carrier signal based on the baseband amplitude component and to generate an amplified RF signal. The transmitter also includes a digital feedback loop in communication with the power amplifier and the baseband processor. The digital feedback loop is configured to detect the amplified RF signal and to provide a digital amplitude feedback signal and a detected phase feedback signal to the baseband processor.

The pulse modulated RF power control method includes an output amplitude control step for controlling amplitude of a pulse output, and a duty control step for controlling a duty ratio of the pulse output. The output amplitude control step performs a constant amplitude control to control an amplitude value of the pulse output so that the amplitude value becomes equal to a set amplitude value. The constant amplitude control according to the output amplitude control, for instance, gives a feedback of the amplitude value of the pulse output outputted by the power control, obtains a difference value between the feedback value and the set amplitude value, and controls the amplitude value of the pulse output so that the difference value becomes zero.

A communication device converts a bit stream to multiple symbols and provides encryption at a physical layer by shifting a phase of each symbol of the multiple symbols to produce multiple encrypted symbols. Each encrypted symbol of the multiple encrypted symbols is modulated with an orthogonal subcarrier to produce at least one modulated subcarrier and the at least one modulated subcarrier is then transmitted via a wireless link. On a receive side, a receiving communication device receives the transmitted, encrypted symbols and provides decryption at a physical layer by shifting a phase of each encrypted symbol in correspondence with the phase used to encrypt the symbol at the transmit side.

Systems and methods for transpositional modulation and demodulation are provided. One such method for generating a signal includes the steps of providing a look-up table having a plurality of quarter-cycle waveforms, each of said quarter-cycle waveforms associated with a respective input level; receiving an input signal; and outputting quarter-cycle waveforms associated with levels of the received input signal. Systems for transpositional modulation are also provided. One such system for generating a signal includes a look-up table having a plurality of quarter-cycle waveforms. Each of the quarter-cycle waveforms are associated with a respective input level, and the look-up table is configured to receive an input signal, and output quarter-cycle waveforms associated with levels of the received input signal.

A digital communications transmitter (100) includes a digital linear-and-nonlinear predistortion section (200, 1800) to compensate for linear and nonlinear distortion introduced by transmitter-analog components (120). A direct-digital-downconversion section (300) generates a complex digital return-data stream (254) from the analog components (120) without introducing quadrature imbalance. A relatively low resolution exhibited by the return-data stream (254) is effectively increased through arithmetic processing. Distortion introduced by an analog-to-digital converter (304) may be compensated using a variety of adaptive techniques. Linear distortion is compensated using adaptive techniques with an equalizer (246) positioned in the forward-data stream (112). Nonlinear distortion is then compensated using adaptive techniques with a plurality of equalizers (226) that filter a plurality of orthogonal, higher-ordered-basis functions (214) generated from the forward-data stream (112). The filtered-basis functions are combined together and subtracted from the forward-data stream (112).

A multi-protocol modulator capable of supporting two or more different modes of operation, each mode of operation corresponding to a different type of modulation, comprises an m-level phase shift keying (m-PSK) modulator which receives a serial input data stream and maps data contained therein into a constellation including m equidistant phases in accordance with a predetermined mapping scheme. The m-PSK modulator is shared by at least two different modulation protocols by allowing the mapping scheme to be selectively changed depending upon the modulation protocol used. The multi-protocol modulator further includes a phase rotator operatively coupled to the output of the m-PSK modulator. The phase rotator selectively rotates the phase of the m-PSK signal by a predetermined phase rotation value. The phase rotator is shared by the two or more modulation protocols by allowing the phase rotation value to be selectively modified depending upon the modulation protocol used. A phase rotated signal is then passed through a pulse shaping filter having a linearized Gaussian response.

A method and apparatus for determining an optimum modulation scheme for a retransmission in a communication system supporting HARQ. When two modulation schemes are available, at an initial transmission, information is modulated in the lower-order modulation scheme if a first MPR is less than a first threshold, and in the higher-order modulation scheme if the first MPR is greater than or equal to the first threshold. Here, an MPR is determined by an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for a transmission. To select one of the modulation schemes for a retransmission, a second MPR is calculated using an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for the retransmission. If the first MPR is equal to or less than a second threshold greater than the first threshold, the lower-order modulation scheme is selected. If the second MPR is greater than the second threshold, the higher-order modulation scheme is selected.

An apparatus for coding a pseudo orthogonal space-time block code in a transmitter using 4 transmission antennas of first to fourth transmission antennas. Upon receiving information symbol streams x1x2x3x4 to be transmitted, a serial-to-parallel converter parallel-converts the received information symbol streams x1x2x3x4 into x1,x2,x3,x4. A pseudo orthogonal space-time block coding (PO-STBC) encoder codes the parallel-converted information symbol streams x1,x2,x3,x4 using a pseudo orthogonal space-time block coding scheme such that the information symbol streams x1,x2,x3,x4 are transmitted via corresponding transmission antennas for first to fourth time periods.

An apparatus for coding a pseudo orthogonal space-time block code in a transmitter using 4 transmission antennas of first to fourth transmission antennas. Upon receiving information symbol streams x1x2x3x4 to be transmitted, a serial-to-parallel converter parallel-converts the received information symbol streams x1x2x3x4 into x1,x2,x3,x4. A pseudo orthogonal space-time block coding (PO-STBC) encoder codes the parallel-converted information symbol streams x1,x2,x3,x4 using a pseudo orthogonal space-time block coding scheme such that the information symbol streams x1,x2,x3,x4 are transmitted via corresponding transmission antennas for first to fourth time periods.

The prevent invention provides a method for performing channel estimation and detection in a Multiple-Input-Multiple-Output (MIMO) system, including: generating a demodulation reference signal, DM-RS, pattern for an extended cyclic prefix (CP); and estimating and detecting channel performance based on the generated DM-RS signal pattern. The DM-RS pattern supports from rank 1 to rank 8 patterns for 8 layer transmission. A transmitter, a receiver and a system thereof are also provided. The solution of the present invention improves channel estimation accuracy, saves channel estimation implementation and implementation complexity at terminals.