Abstract: The amplitude control circuit of the present invention can reduce output noise and suppress a decrease in reception sensitivity. An amplitude control section (120), which is an amplitude control circuit, is provided with: a DA converter (121) that converts amplitude data into differential amplitude signals and outputs the differential amplitude signals; a level control section (122) that controls the levels of the differential amplitude signals according to transmission power information P; and an offset calculating section (123) that assigns the DC voltage based upon transmission power information P to the differential amplitude signals subjected to level control in the level control section (122).

Abstract: An apparatus and a system, as well as a method and article, may operate to send a selected data type without self-definition information to a receiver if a state capable of interpreting the selected data type has been maintained by the receiver, and to send the selected data type with the self-definition information to the receiver if the state capable of interpreting the selected data type has not been maintained by the receiver.

Abstract: Hardware and processes are provided for efficient interpretation of multi-value signals. The multi-value signals have a first voltage range with is used to indicate multiple numerical or logical values, and a second voltage range that is used to provide control functions. In one example, the multi-value circuitry is arranged as a set of rows and columns, which may be cascaded together. The control function can be implemented to cause portions of rows, columns, or cascaded connections to be powered off, thereby saving power and enabling more efficient operation.

Abstract: Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Abstract: The present invention relates to an apparatus and a method for measuring an in phase and quadrature (IQ) imbalance. One embodiment according to the present general inventive concept can provide a method for measuring a Tx IQ imbalance generated in an IQ up-conversion mixer and an Rx IQ imbalance generated in an IQ down-conversion mixer, that includes measuring a first IQ imbalance corresponding to a first combination of the Rx IQ imbalance with the Tx IQ imbalance, measuring a second IQ imbalance corresponding to a second combination of the Rx IQ imbalance with the Tx IQ imbalance and obtaining the Tx IQ imbalance and the Rx IQ imbalance from the first IQ imbalance and the second IQ imbalance.

Abstract: An amplitude signal and a frequency signal are generated through processing of data. The frequency signal is angle modulated. The amplitude signal is adjusted based on a delay time and is amplitude amplified. The resultant signal from the angle modulation is amplitude modulated based on the resultant signal from the amplitude amplification to obtain a modulated signal. The modulated signal is used to calculate a delay between the amplitude signal and the frequency signal, which is used for feedback control of the delay time by which the amplitude signal is adjusted until no delay exists only in a test period. Through the signal generating, a sinusoidal signal is outputted as each of the amplitude signal and the frequency signal during the test period.

Abstract: A polar transmitter includes: a processor arranged to convert signals from a specific coordinate system to a polar coordinate system, wherein the signals in the polar coordinate system comprises a phase component and an amplitude component; a PM path configured to have a constant PM group delay, for processing the phase component; an AM path, of which an AM group delay is capable of being determined, for processing the amplitude component; and an adjustable delay circuit, arranged to adjust delay of the signals in the specific coordinate system according to the constant PM group delay and the calibrated AM group delay.

Abstract: In the field of communications, a method for generating a modulated signal and a transmission device are disclosed. The method for generating a modulated signal includes: generating first monochromatic light and second monochromatic light between which a frequency difference exists ; modulating the first monochromatic light and the second monochromatic light respectively to obtain a first modulated optical signal and a second modulated optical signal; superimposing the first modulated optical signal and the second modulated optical signal to obtain a hybrid optical signal; and performing photoelectric conversion on the hybrid optical signal to obtain a modulated signal.

Abstract: An encoder encodes sound data and the like to generate a binary signal. A mapper converts the binary signal into a four-level symbol and outputs the four-level symbol. A base band filter includes a root raised cosine filter and a sinc filter. The base band filter blocks a predetermined frequency component of a symbol to shape the symbol into a waveform signal and outputs the waveform signal shaped. An FM modulator transmits a signal subjected to FM modulation according to a magnitude of an amplitude of a waveform signal to a receiving unit. When a symbol of ±3 is outputted from the mapper, a frequency shift of a signal transmitted from the FM modulator has a predetermined value in a range of ±0.822[kHz] to ±0.952[kHz]. This makes it possible to provide a modulating apparatus, a mobile communication system, a modulating method, and a communication method that use a modulating method that can conform to the FCC rule to be enforced in 2005 without using a linear power amplifier.

Abstract: An output control unit outputs data of bit rate A to a first header-attaching unit and data of bit rate B to a second header-attaching unit. An instructing unit instructs the first or the second header-attaching unit to attach a header of bit rate being the least bit rate to the data of bit rate A or B. The first header-attaching unit creates a header of bit rate A, including an ID of a destination ONU of the data of bit rate A and information concerning the data length, and attaches the header of bit rate A to the data of bit rate A. The second header-attaching unit creates a header of bit rate A, including an ID of the destination ONU of the data of bit rate B and information concerning the data length, and attaches the header of bit rate A to the data of bit rate B.

Abstract: A method and apparatus for providing an asymmetrical backwards compatible communications signal that is capable of being decoded by QPSK and OQPSK receivers as well as PSK and QAM receivers is provided. The invention comprises a timing error accumulator coupled to a first bit stream. The first bit stream includes content that is common to the QPSK/OQPSK receiver and to the PSK/QAM receiver. A phase error accumulator is coupled to a second bit stream and adjusts the phase of symbols in the second bit stream. A phase and timing error compensator is coupled to the phase error accumulator and the timing error accumulator and adjusts the first and second bit streams received from the phase error accumulator and the timing error accumulator in order to reduce timing and phase errors. A higher order modulator coupled to the phase- and timing error compensator is also provided. The higher order modulator processes the first and second bit streams to provide the asymmetrical backwards compatible signal.

Abstract: Apparatus and methods for improving the spectral performance of a polar modulator are described. A composite FM signal component of a composite polar transmit signal may be processed by monitoring the FM signal to detect a transient burst component, and, responsive to detection of a transient burst, generating a spectrally friendly replacement signal component that may be combined with the FM signal to improve spectral performance of the composite signal. In addition, an associated AM component of the composite transmit signal may be filtered to further improve spectral performance.

Abstract: Examples disclosed herein provide for a method for transmitting a signal. The method includes generating a Manchester encoded data stream and combining the Manchester encoded data stream with an amplified clock signal to produce an amplitude modulated signal having a zero crossing at each edge of the amplified clock signal. The amplitude modulated signal can then be sent over a communication medium.

Abstract: The present invention relates to estimating a direct current (DC) offset of a radio frequency (RF) receiver when an estimated amplitude of a continuous-transmission amplitude-modulated (AM) RF signal is below a first threshold and when the RF receiver is not receiving an RF input signal. The estimated DC offset of the RF receiver may be used to improve RF receiver performance, particularly over temperature and supply voltage variations. Estimating the DC offset of the RF receiver when the estimated instantaneous amplitude of the continuous-transmission AM RF signal is below the first threshold may minimize errors in the estimated DC offset.

Abstract: Transmitter device which includes at least: a) one delay line designed to output M signals which are delayed in relation to each other, where M is an integer greater than 1; b) a memory, designed to store at least M digital samples of a waveform, where each digital sample contains N bits, and to output each of the M digital samples successively on N output lines respectively under the control of one of the M delayed signals; and c) a digital-analog converter which includes N inputs linked to N output lines, designed to convert the M digital samples received as input from the N output lines of the memory and to successively output, on an output of the digital-analog converter, each of the M analog converted digital samples which together form an analog signal which is representative of the waveform.

Abstract: A polar modulator including a signal converter configured to provide a phase signal and an amplitude signal based on at least one received signal is disclosed. A digital-to-analog converter is coupled to the signal converter, the digital-to-analog converter configured to receive an augmented signal, wherein a polarity of the augmented signal is selected to minimize an absolute phase change for sequential signals. A signal mixer is coupled to the digital-to-analog converter to receive an analog signal generated from the augmented signal.

Abstract: A system, method and node for modulation and coding scheme adjustment for a Long Term Evolution (LTE) shared Data Channel. The method determines an actual number of orthogonal frequency division multiplexing (OFDM) symbols, NOS utilized for the shared Data Channel. A modulation order for transmission of data on the shared Data Channel is increased when the actual number of OFDM symbols NOS is less than 11 and decreased when NOS is more than 11. A modulation and coding scheme field (IMCS) of a downlink control information of the shared Data Channel may also be determined. If 0?IMCS+11?NOS?28, the modulation order is modified by utilizing a factor of (IMCS+11?NOS) in a standardized modulation scheme. If it is determined that IMCS+11?NOS<0, the modulation order is set to Quadrature Phase Shift Keying (QPSK). If it is determined that IMCS+11?NOS>28, the modulation order is set to 64 Quadtrative Amplitude Modulation (64QAM).

Abstract: A polar modulator of the present invention includes: a first function block which generates an amplitude signal and a phase signal; a second function block which adjusts the signal delay between the amplitude signal and the phase signal; a third function block which allows the low frequency component of the amplitude signal to pass therethrough; a fourth function block which modulates the phase of the phase signal; a fifth function block which outputs a modulation voltage, based on the amplitude signal; a sixth function block which modulates the amplitude of the phase signal, based on the modulation voltage; a seventh function block which measures the temperature of at least one function block; and an eighth function block which calculates a compensation amount for the signal delay, based on the measured temperature. The second function block adjusts the signal delay, based on the compensation amount.

Abstract: A method and apparatus for utilizing code division multiple access in modulated reflectance transmissions comprises the steps of generating a phase-modulated reflectance data bit stream; modifying the modulated reflectance data bit stream; providing the modified modulated reflectance data bit stream to a switch that connects an antenna to an infinite impedance in the event a “+1” is to be sent, or connects the antenna to ground in the event a “0” or a “?1” is to be sent.

Abstract: There is an apparatus and technique for generating a sequence of modulated waveforms of finite duration in which the difference in start time of each waveform is shorter than the waveform's overall duration and each waveform in the sequence has independent data modulation imparted upon it. The apparatus consists of a bank of memory cells arranged in an N×M configuration with associated control circuitry, along with an arrangement scheme for the data in the N×M memory cells such that the waveforms will be correctly reproduced when the memory cells are addressed by the control circuitry in the prescribed order.

Abstract: Provided is a transmission circuit which allows smooth switching of the operation mode when switching the operation mode of the transmission circuit. A power amplifier 14 includes: a first input terminal to which a direct-current voltage or a voltage in accordance with an amplitude signal M is supplied; a second input terminal to which an output signal from a first variable gain amplifier 171 or an output signal from a second variable gain amplifier 172 is inputted; and a third input terminal to which an output signal from a first bias circuit 15 or an output signal from a second bias circuit 16 is inputted. A control section 11 switches the operation mode of the transmission circuit so that at least one of the first input terminal, the second input terminal, and the third input terminal of the power amplifier is prevented from being in a no input state.

Abstract: In accordance with various exemplary embodiments of the present invention, systems, methods and devices are configured to facilitate RF envelope amplitude control. For example, a RF envelope amplitude control system comprises: a RF amplifier, wherein the RF amplifier is associated with a feedback device that is configured to create a first feedback signal representing the power in an RF output signal; a transmit waveform generator configured to generate a reference waveform signal; an adaptive table waveform generator configured to compare the reference waveform signal and the first feedback signal and to create a second feedback signal based on that comparison; and a loop filter configured to combine the reference waveform signal, the first feedback signal, and the second feedback signal to form an amplifier control signal, wherein the amplifier control signal is provided to the RF amplifier to adjust the RF output signal to conform to a specified RF envelope.

Abstract: Modulators for amplitude-modulating signals defined by phase information and envelope codes are provided with first transistors for receiving the phase information and second transistors for receiving the envelope codes. The first main electrode of one transistor is coupled to the second main electrode of the other transistor and the other second main electrode constitutes an output of the modulator. This modulator can be used in any kind of transistor environment and is simple and low cost. The doped areas of the coupled first and second main electrodes comprise an overlap to reduce cross-talk and to reduce silicon area. Polar transmitters are provided with this modulator and with a circuit for generating a phase/frequency code and the envelope code and with an oscillator for receiving the phase/frequency code and for generating the phase information. A phase shift between the phase information and the envelope code reduce aliases.

Abstract: A reference voltage adjustment unit (212) calculates gain from a DA converter (121) to an offset calculating unit (123) by detecting the output of the offset calculating unit (123), adjusts the reference voltage (V3) from a reference voltage generation unit (211) so that the value becomes a predetermined value, and feeds the post-adjustment reference voltage (V4) to the DA converter (121) and offset calculating unit (123). Due to this, the gain from the DA converter (121) to the offset calculating unit (123) can be corrected. Fluctuation in the lower limit level of the output of a differential-to-single conversion unit (124) can be minimized as a result, so, the addition of unnecessary offset to the amplitude data at the amplifier unit (140) can be minimized. Thus, deterioration in modulation characteristics when the amplitude control unit (210) takes a differential circuit configuration can be minimized.

Abstract: A data transmitter (A, B, C, D) wherein, in a first operating mode, the first and second carrier signals are mutually phase-shifted, and the data module generates said first and second data signals based on different data, so as to produce, at the transmitter's output, a modulated signal exhibiting a first constellation of states (A, B, C, D) in a complex plane, and, in a second operating mode of the transmitter, the data module generates said first and second data signals correlated with one another based on common data, so as to produce, at the transmitter's output, a modulated signal exhibiting a second constellation of states (A, D; E, F) in the complex plane that is more reduced and more dispersed then said first constellation of states.

Abstract: Aspects of a method and system for enhancing efficiency by modulating power amplifier (PA) gain are presented. Aspects of the system may comprise a PA gain modulator that enables modification of an amplitude of a digital baseband signal. A baseband processor may enable computation of a first gain value based on the modification. The baseband processor may enable computation of a second gain value based on the first gain value. A PA may enable generation of an RF output signal based on the modified digital baseband signal and the second gain value.

Abstract: The disclosed polar modulation transmitter circuit is configured to generate an output signal having a transmission frequency that minimizes crosstalk effects between different transmission bands (e.g., Bluetooth, GSM, UMTS, etc.). In particular, a polar modulation transceiver circuit, having an amplitude modulated (AM) signal and a phase modulated (PM) signal, comprises a digitally controlled oscillator (DCO) configured to generate a DCO signal having a DCO frequency. The DCO signal is provided to one or more frequency dividers that are configured to selectively divide the DCO signal to generate various lower frequency signals, used to select a sampling rate for a DAC operating on the AM signal and an RF carrier signal frequency, which result in an output signal having a frequency that does not interfere with other RF systems on the same IC (e.g., that falls outside of the downlink frequency of other RF systems). Other systems and methods are also disclosed.

Abstract: Apparatus and methods for adjustment of spectral signal characteristics in polar modulators are described. A composite signal detection circuit is configured to detect when a signal trajectory of a composite signal provided to the polar modulator passes near the origin of a complex plane associated with the composite signal, and then adjusts the composite signal to pass through the origin. A spectral adjustment circuit is described to adjust AM and FM or PM components of the composite signal to reduce the deviation of an FM component of the composite signal.

Abstract: A polar transmitter includes a power amplifier (PA), an amplitude modulation (AM) path including an AM path adjustable delay, an AM path delay measurement circuit, a phase modulation (PM) path including a PM path adjustable delay, and a PM path delay measurement circuit. The AM path delay measurement circuit is configured to measure an AM path delay using waveform correlation, e.g., using peak magnitude events (PMEs) in signals transmitted along the AM path to a power supply port of the PA. The PM path delay measurement circuit is configured to measure a PM path delay using waveform correlation, e.g., using PMEs in signals transmitted along the PM path to a phase-modulated input of the PA. The measured AM and PM path delays are used to adjust the AM and PM path adjustable delays, to reduce the delay mismatch between signals appearing at the power supply and phase-modulated input ports of the polar transmitter's PA.

Abstract: A radio channel estimation technique is described for use in a OFDM-based radio communications system. A block of OFDM symbols is transmitted from multiple antennas over multiple sub-carrier frequencies. The block of OFDM symbols includes known pilot symbols as well as data symbols to be determined by a receiver. The pilot symbols are transmitted in a predetermined pattern at periodic times on periodic sub-carriers. A pilot channel estimate is determined for each pilot symbol in the received block of OFDM symbols. An N×M matrix of points corresponding to the received OFDM symbol block is formed. N is the number of sub-carriers and M is the number of OFDM symbols in the OFDM symbol block. The matrix is formed by inserting pilot channel estimates at predetermined positions in the N×M matrix according to the predetermined pilot pattern and inserting zeros in remaining positions in the N×M matrix.

Abstract: An amplitude of a carrier signal at an output of an impedance matching block is measured as a first amplitude value. A value of the signal amplitude at the output of the impedance matching block is calculated as a second amplitude value that a signal resulting from amplitude modulation with said modulation factor from said carrier signal should assume, said carrying signal having an amplitude with the first amplitude value. A setting of a transmitter is changed to decrease the carrier signal amplitude at the output of the impedance matching block. An amplitude of a new carrier signal at the output of the impedance matching block is measured as a new amplitude value. The transmitter setting keeps changing so many times until the new amplitude value is equal to or lower than said second amplitude value or within a predetermined tolerance range around said second amplitude value.

Abstract: The present invention relates to a transmitting device and to a receiving device.

Abstract: A transmitter for transmitting and calibrating a phase signal and an amplitude signal. The transmitter comprises a phase modulation path, an amplitude modulation path, and a control unit. The phase modulation path transmits the phase signal. The amplitude modulation path transmits the amplitude signal. The control unit delays the signal on at least one of the phase modulation path and the amplitude modulation.

Abstract: An RF transmitter includes a Cartesian to polar conversion section, a PLL, a DAC module, a mixing module, and a PA module. The Cartesian to polar conversion section converts a Cartesian based symbol stream into a polar based symbol stream. The PLL generates an oscillation when the RF transmitter is in a Cartesian mode or a phase modulated oscillation based on phase modulation information of the polar based symbol stream when the RF transmitter is in a polar mode. The mixing module mixes an analog Cartesian based signal with a local oscillation to produce a Cartesian based up converted signal when the RF transmitter is in the Cartesian mode and mixes an analog amplitude signal with a phase modulated local oscillation to produce a polar based up converted signal when the RF transmitter is in the polar mode.

Abstract: A high-speed transmitter and receiver are provided. In one embodiment, a transmitter comprises a baseband processor structured to receive data and to convert the data into a multiplicity of high and low signal values, with each high and low signal value having a first timing interval. A local oscillator generates a clock signal at a second timing interval and a digital circuit combines the high and low signal values with the clock signal to produce a transmission signal directly at a transmission frequency. A receiver is configured to receive the signal. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Abstract: An amplifier includes a separating unit, a generator, first to fourth switching amplifiers, and an outputting unit. The separating unit separates a pulse signal into a first separated pulse signal and a second separated pulse signal. The generator generates first to fourth low speed pulse signals by using the first and the second separated pulse signal. The first switching amplifier amplifies the first low speed pulse signal. The second switching amplifier amplifies the second low speed pulse signal by using the output of the first switching amplifier as a power-supply. The third switching amplifier amplifies the third low speed pulse signal. The fourth switching amplifier amplifies the fourth low speed pulse signal by using the output of the third switching amplifier as a power-supply. The outputting unit combines and outputs the first and the second output pulse signal.

Abstract: A diversity transmission scheme uses a number of antennas that is greater than the limitation of two transmitting antennas in the well-known Alamouti scheme. In an embodiment comprising four antennas, the antennas transmit in pairs such that each antenna transmits a block that is used in the Alamouti scheme. This increases the transmission rate. For example, the transmission of two signals at a given time slot increases transmission rate by a factor of two. The invention not only increases the number of antennas, but also increases the transmission rate. At the receiver end, the code is decoded without matrix inversion and without much noise enhancement. Moreover, noise enhancement stability is increased by a simple, partial interference cancellation scheme, that results in improved decoding performance.

Abstract: Disclosed is a transmission apparatus, a radio communication apparatus, and a transmission method for making it possible to obtain stable characteristics by controlling the difference of time between an amplitude signal and a phase signal to an optimal point, without depending on a modulated signal nor making the circuit size larger. A multiplier (170) generates, in a pseudo manner, a digital modulated signal corresponding to a signal that is obtained by performing analog to digital conversion on a modulated signal that is generated by an amplitude modulator (140), by multiplying a digital amplitude signal that is obtained by performing analog to digital conversion on an amplitude signal by a digital angle modulated signal corresponding to a signal that is obtained by performing analog to digital conversion on an angle modulated signal.

Abstract: Disclosed is a method, circuit and system for transmission and reception of data, including video data. There is provided a multi-constellation data to symbol mapping logic, circuit or module integral with or otherwise functionally associated with a transmitter and a corresponding multi-constellation symbol to data de-mapping logic, circuit or module integral or otherwise functionally associated with a receiver. The multi-constellation mapping and corresponding de-mapping logic, circuit or module may be characterized by a non-uniform distribution of symbols, and optionally may be characterized by a set of symbol clusters, wherein symbol clusters are of the same or varying sizes and may be spaced either at uniform or non-uniform distances from one another.

Abstract: Provided is a measuring apparatus which measures a quadrature modulator, including a supplying section supplying the quadrature modulator with a reference I signal having a predetermined frequency and a reference Q signal whose phase is shifted by 90 degrees from the reference I signal, an extracting section extracting, from a modulation signal output from the quadrature modulator by applying quadrature modulation to the reference IQ signals, a main signal component as the reference IQ signals modulated, and an image signal component occurring at a position symmetric to the modulated reference IQ signals with respect to the carrier signal, and a measurement value calculating section calculating at least one of a carrier phase error and amplitude error which occur between I signal and Q signal sides of the quadrature modulator, and a skew between IQ signals of the quadrature modulator, based on the main signal component and image signal component.

Abstract: A method of transmitting data that includes controlling generation of bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks; and performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: A radiofrequency transmitting device delivers output signals having a chosen radiofrequency from input data split up into complementary phase data and amplitude data. This device includes a radiofrequency reference oscillator for outputting a reference signal having a fixed radiofrequency reference, and a digital phase modulator for synthesizing the chosen radiofrequency from the fixed radiofrequency reference and for phase modulating the reference signal with the phase data, in order to produce an output signal having the chosen radiofrequency.

Abstract: A multiple-mode modulator is configured similarly to a direct conversion quadrature modulator with an infusion of an amplitude modulation signal path from a large signal polar modulator to improve the power amplifier efficiency. The multiple-mode modulator also includes a radio frequency signal path. The multiple-mode modulator is configured to receive a baseband signal, convert the baseband signal to a radio frequency (RF) signal, and to process the RF signal according to either a polar mode or a quadrature mode, depending on a time-varying input voltage of the RF signal. When the power amplifier operates in the linear region, the RF signal is processed according to the quadrature mode. When the power amplifier operates in the compressed region, the RF signal is processed according to the polar mode. The multiple-mode modulator can be configured according to a small signal polar architecture or a large signal polar architecture, having either an open-loop or closed-loop configuration.

Abstract: An apparatus comprising at least two controllers each providing control information for controlling phase or frequency of a digital signal, a combiner for combining control information from the at least two controllers to combined control information and a phase rotator for adjusting, by using phase rotation, one or more of the phase and the frequency of the digital signal on the basis of the combined control information.

Abstract: A transmitting apparatus, that includes a means for generating bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks and a modulator for performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: A radio device (10) receives signals from a radio device (20) through a plurality of downlink channels that have different frequencies, decides modulation formats that have transmission performances based on qualities of the received signals for the individual downlink channels, and transmits modulation format setup information in which respective pieces of information that represent the decided modulation formats for the individual downlink channels are combined into one piece to the radio device (20) through a plurality of uplink channels that have different frequencies. The radio device (20) refers to modulation format setup information received through at least one of the plurality of uplink channels and sets up modulation formats for signals transmitted through the plurality of downlink channels based on the modulation format setup information.

Abstract: A method for amplitude modulating a carrier signal according to one embodiment includes splitting the carrier signal into first and second paths; phase modulating the carrier signal on the first path; phase modulating the carrier signal on the second path; combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal; and wherein a first feedback loop couples the amplitude modulated output signal to circuitry for phase modulating the carrier signal on the second path but not to circuitry for phase modulating the carrier signal on the first path, the first feedback loop being for reducing a residual phase variation of the amplitude modulated output signal. Additional systems and methods are also presented.

Abstract: An apparatus including a spin torque oscillator configured to receive an input electric current and to produce a radio frequency output signal; and a tunable current source for providing an input electric current to the spin torque oscillator.

Abstract: A data transmitting and receiving method of transmitting supplementary data in an OFDM communication system is disclosed. The method of transmitting and receiving the OFDM signal includes: mapping an input bit stream into at least one transfer symbol; changing at least one of amplitudes and phases of the transfer symbols that are transmitted by a specific sub-carrier group having a plurality of sub-carriers using constellation modification information to indicate specific additional data; and transmitting the transfer symbols, to which the changing is carried out, to a receiving end by an orthogonal frequency division multiplexing data processing, the constellation modification information being identical to each other with respect to the transfer symbols that are transmitted by the specific sub-carrier group.

Abstract: An input digital signal is periodically and alternately subjected to first modulation and second modulation, being thereby converted into a pair of a baseband I signal and a baseband Q signal. The first modulation and the second modulation are different from each other. The pair of the baseband I signal and the baseband Q signal are outputted. The first modulation may be at least 8-signal-point modulation while the second modulation may be phase shift keying.