Abstract: The present invention aims to provide a transmission device that, in a communication system using multilevel modulation with 2^n levels (n being an integer greater than or equal to two), limits the run length to a predetermined value or less and guarantees DC balance. The transmission device, which transmits data to which 2^n amplitude modulation has been applied, separates data for transmission into n data sequences; encodes one of the n data sequences to guarantee run length, thereby generating a converted data sequence; generates an intermediate data sequence by either inverting or not inverting a specific data sequence so that, based on candidate data, the next output voltage guarantees DC balance; and applies 2^n amplitude modulation to n-bit symbols each of which has a bit in the intermediate data sequence as a most significant bit and bits in the remaining data sequences, excluding the specific data sequence, as subsequent bits.

Abstract: A technique for adjusting a phase relationship among modulation symbols is disclosed. A method embodiment of this technique comprises the steps of applying to a sequence of modulation symbols a phase ramp that continuously increases over the duration of the symbol sequence, and applying a compensation phase to each modulation symbol to introduce a phase offset between two subsequent modulation symbols. The joint application of the phase ramp and the compensation phase can be used to establish a saw tooth-like phase characteristic over the sequence of modulation symbols. In one embodiment, the phase ramp is applied in the context of impressing a frequency shift on the modulation symbols.

Abstract: In a destuff circuit, after invalid data included in each data signal assigned to a plurality of lanes in a stuff shifter is collected to one side within the same column, then in a data rotator the number of stuffs of the respective data signals of each column is detected, and the data of the respective columns are operated to rotate in one direction, according to the detection results. Then, effective data included in the data signal of each lane that has been rotated is stored in FIFO, to thereby output signals for which ineffective data has been removed and only effective data has been extracted. As a result, it becomes possible to perform destuffing processing for parallel data signals with simple logical circuits at high speed.

Abstract: A communication channel is operated by storing a calibrated parameter value in nonvolatile memory during manufacturing, testing, or during a first operation of the device. Upon starting operation of the communication channel in the field, the calibrated parameter value is obtained from the nonvolatile memory, and used in applying an operating parameter of the communication channel. After applying the operating parameter, communication is initiated on a communication channel. The operating parameter can be adjusted to account for drift immediately after starting up, or periodically. The process of starting operation in the field includes power up events after a power management operation. In embodiments where one component includes memory, steps can be taken prior to a power management operation using the communication channel, such as transferring calibration patterns to be used in calibration procedures.

Abstract: A communications transmitter configured to reduce the average-to-minimum magnitude ratio (AMR) of a communications signal includes a symbol mapper, a pulse-shaping filter, an AMR reduction circuit, and a modulator. The symbol mapper operates to generate a sequence of symbols from a binary-source data stream containing a message to be transmitted, and the pulse-shaping filter generates a baseband signal based on the sequence of symbols. The AMR reduction circuit is configured to compare a magnitude of a local minimum of samples of the baseband signal to various magnitude threshold levels, and to modify the baseband signal in one of two manners depending on the relationship of the magnitude of the local minimum and the various threshold levels. Finally, the modulator operates to modulate a carrier signal based on the modulation information contained in the modified baseband signal.

Abstract: An apparatus for providing a data encoding scheme may include an encoder. The encoder may be configured to determine, for a digital input value comprising a particular number of bits, whether more than half of the bits of the digital input value have a high value. The encoder may be further configured to encode the digital input value by inverting each of the bits of the digital input value in response to a determination that more than half of the bits of the digital input value have the high value. Corresponding method and computer program product, and a decoder and decoding method are also provided.

Abstract: Freedom for relationship between division of a signal processing unit and a pilot signal is improved in a multi-carrier communication system such as OFDM. An encoded signal is divided into resource blocks and the signals are arranged independently of the arrangement of a pilot signal. The signal arranged at the same position as the pilot signal causes a puncture upon transmission.

Abstract: Provided are a transmitting system including a pulse amplitude modulator section that pulse amplitude modulates an input signal into a set of first and second pulse amplitude modulated signals, a first frequency signal output section that outputs a first frequency signal, a first amplitude shift keying modulator section that amplitude shift keying modulates, using the first frequency signal, the first pulse amplitude modulated signal into an amplitude shift keying modulated signal, an adder section that adds together the amplitude shift keying modulated signal and the second pulse amplitude modulated signal to generate a transmission signal, and a transmitter section that transmits the transmission signal, a transmitting method, a receiving system for receiving the signal transmitted from the transmitting system and a receiving method.

Abstract: Provided is a transmitter including a polar modulation circuit which adjusts a timing lag between an amplitude component and a phase component more accurately than a conventional art. The polar modulation circuit includes: a first calculator for performing an exclusive OR logical operation between the amplitude component before and after being inputted to the first processing section; a second calculator for performing an exclusive OR logical operation between the phase component before and after being inputted to the second processing section; and a delay fluctuation detection/compensation section for obtaining a delay time of the amplitude component based on an amount of output accumulation of the first calculator; obtaining a delay time of the phase component based on an amount of output accumulation of the second calculator; detecting an amount of delay fluctuation by using the delay times; and adjusting timings of the amplitude component and the phase component.

Abstract: The circuit is provided for the transmission of data amplitude modulated radio frequency signals. The circuit includes a local oscillator for generating an oscillating signal at a determined carrier frequency, a unit for shaping data pulses to supply a data amplitude modulation control signal (Vmod), and a power amplifier receiving the oscillating signal and the data amplitude modulation control signal (Vmod) for the transmission of data amplitude modulated radio frequency signals by an antenna or an antenna arrangement. The data pulse shaping unit (13) includes a pulse shaper (21) for digitally adapting the data transition edges on the basis of an incoming digital data signal (d), and a digital-analogue conversion stage (26, 27) for converting a digital data signal shaped in the unit, in order to supply the data amplitude modulation control signal (Vmod) to the power amplifier.

Abstract: It is possible to provide a radio transmission device and a radio transmission method which can avoid degradation of a channel estimation accuracy using a reference signal formed by a ZC sequence even when the RS transmission band of a local cell is different from that of an adjacent cell. A mobile station decides a cyclic shift sequence corresponding to RB allocation information from an RS table which correlates different frequency bandwidths from a reference point of respective transmission bands to a spectrum start number of the cyclic shift sequence so as to satisfy a particular relationship based on the sequence length and transmits the decided cyclic shift sequence as RS to a base station. The base station uses the same RS table as the RS table of the mobile station and performs correlation calculation of the RS transmitted from the mobile station, thereby performing channel estimation.

Abstract: A method, system, apparatus and article are described for optimizing transformer power combiners and for dynamically controlling power for outphasing power amplifiers. In some embodiments, for example, an apparatus may comprise one or more outphasing power amplifiers, one or more phase modulator modules coupled to and operative to dynamically control the one or more outphasing power amplifiers, and one or more power combiners coupled to and operative to combine outputs from the one or more outphasing power amplifiers, wherein the one or more power combiners comprise transformer power combiners arranged to combine outphasing signals using a primary inductor and differential signals using a secondary inductor. Other embodiments are described and claimed.

Abstract: An RF signal generator divides an input radio signal into an amplitude signal and a phase signal and outputs the amplitude signal and the phase signal. A switching amplifier amplifies the radio signal with the amplitude signal and the phase signal. The switching amplifier includes at least one variable current sources that is controlled by the amplitude signal and supplies a current to the switching amplifier. The switching amplifier includes at least one switching elements that connects the variable current sources to one of a terminal connected a ground potential and an output terminal of the switching amplifier according to the phase signal.

Abstract: A method and system for increasing the throughput of a wireless channel that sends different data on different multi-path components. The channel can be pre-mapped or dynamically mapped, and the different transmissions can be modulated by different complexity signals such as adaptive quadrature amplitude modulation (AQAM). Each multipath component is coded with a signature that will allow it to be separated at a receiver that has an omni-directional antenna. Common signature techniques can be offset PN codes, orthogonal spreading vectors, orthogonal alphabets and other signature techniques. The received channels can be combined for an overall increase in data-rate or used separate as multiplexed data.

Abstract: A circuit for providing AM/PM modulation is described. The circuit includes a signal generator, which provides two phase modulated (PM) signals used to form two drive signals which are later combined in a constructive/destructive fashion. The combination of the two phase modulated signals form a signal for driving a load. When the load is driven, the resulting signal is AM/PM modulated.

Abstract: A transmission circuit (100) according to the present invention includes an RF-IC (110), an EM-IC (120), and a power amplifier (130). The EM-IC (120) includes a DC-DC converter (123), a transistor (124), a low-dropout regulator (121), and a regulator output selector switch (122). After an elapse of a predetermined time from a time when an operation mode of the transmission circuit has switched from a polar modulation mode to a quadrature modulation mode to a time when a power supply voltage for the quadrature modulation mode output from the DC-DC converter (123) stabilizes at a desired value, the regulator output selector switch (122) switches a connection destination of a gate of the transistor (124) to a fixed potential, and outputs as a control voltage the power supply voltage for the quadrature modulation mode output from the DC-DC converter (123).

Abstract: A square array of signal points forming a 22n-QAM signal constellation, where n=3, 4, is modified by relocating the inner most 22n/16 and outer 22n/16 constellation points to specific positions, resulting a modified-square constellation with a reduced peak to average power ratio (PAPR) at the modulator output relative to that of the square constellation while resulting in a receiver sensitivity that is degraded by less than the decrease in the modulator's PAPR and hence less than the possible improvement at the transmitter in average transmitted power.

Abstract: Implementations of a high gain range transmitter with variable-size mixers are described.

Abstract: The present invention relates to the field of data transmission. The invention has application to amplifiers, the transmission of data modulated signals, filters and/or matching circuits connected between an amplifier and a load, radio transmitters, the transmission of data modulated radio signals, filters and/or matching circuits used between a transmitter's power amplifier and an antenna and the field of Radio Frequency Identification (RFID), such as in the transmission of data between a tag and an interrogator. The present invention enables the transmission of phase modulated signals, by adjusting a device's tuning to substantially match the instantaneous frequency of the phase modulated signal.

Abstract: A transmitter using quadrature modulation includes a rectangular to polar converter for converting data symbols into a polar form, where each polar symbol has a magnitude signal and an angle signal. Digital phase modulation circuitry includes an all digital PLL circuit for generating a phase modulated RF carrier signal responsive to the angle signal frequency control word (FCW) and a carrier frequency FCW. A digitally controlled amplifier for amplifying the phase modulated signal is controlled by a digital amplitude control circuitry for controlling the gain of the digitally controlled amplifier responsive to the magnitude signal.

Abstract: Digital transmitters having improved characteristics are described. In one design of a digital transmitter, a first circuit block receives inphase and quadrature signals, performs conversion from Cartesian to polar coordinates, and generates magnitude and phase signals. A second circuit block (which may include a delta-sigma modulator or a digital filter) generates an envelope signal based on the magnitude signal. A third circuit block generates a phase modulated signal based on the phase signal. The third circuit block may include a phase modulating phase locked loop (PLL), a voltage controlled oscillator (VCO), a saturating buffer, and so on. A fourth circuit block (which may include one or more exclusive-OR gates or an amplifier with multiple gain states) generates a digitally modulated signal based on the envelope signal and the phase modulated signal.

Abstract: A mobile terminal and method of controlling a driving voltage of a power amplifier therein are provided. The present invention includes a power amplifier module having a plurality of operative modes, the power amplifier module configured to amplify a power strength of an RF signal, a modem configured to deliver the RF signal to the power amplifier module, and to control the operative modes of the power amplifier module, a power detecting unit configured to output a reference voltage by detecting the power strength of the RF signal outputted from the power amplifier module, and a DC/DC converter configured to supply a driving voltage to the power amplifier module by adjusting a detected power value according to a gain corresponding to each of the operative modes of the power amplifier module.

Abstract: A method and system is provided for communicating distinct data over a single frequency using on-off keying, a form of amplitude modulation, or phase changes timed to the zero crossing point of the carrier. A data signal is synchronized with the carrier by adding padding bits so that the number of bits is equal to the frequency of the carrier. The carrier is then modified by attenuating the carrier as needed once per cycle. Said carrier is then transmitted. The resulting transmitted carrier carries a number of bits equal to the transmit frequency. At the receive end, the received signal is compared to a sine wave to determine if the incoming signal is at full strength or at reduced strength, allowing for the detection of encoded digital information. In a another embodiment, the phase of the carrier is changed instead of attenuating the carrier, timed to the carrier cycles,once or twice per cycle.

Abstract: An asynchronous delta-sigma modulator is proposed that comprises an input port, a filter, an envelope path, a phase path, an amplifier, and a feedback path that conveys the amplifier output signal to the filter. The envelope path extracts an envelope from the signal provided by the filter and issues an envelope signal. The phase path processes or processes a phase from the signal provided by the filter and issues a phase signal. The amplifier comprises input ports for the envelope signal and the phase signal. The amplifier issues an amplifier output signal based on said envelope signal and said phase signal. The feedback path conveys the amplifier output signal to the filter. The feedback signal contains both amplitude information and phase information. A corresponding method and computer-program products usable for production and operation of the delta-sigma modulator are also disclosed.

Abstract: A differential radio frequency signal transmitter is provided. The differential radio frequency signal transmitter includes an oscillator, a modulator and an amplifier module. The oscillator generates a pair of differential oscillation signals. The modulator generates a pair of differential modulated signals according to an input signal and the pair of differential oscillation signals. The input signal is a digital signal. When the input signal is at a first state, the modulator outputs the pair of differential oscillation signals as the pair of differential modulated signals, and when the input signal is at a second state, the modulator outputs a constant voltage signal as the pair of differential modulated signals. The amplifier module receives and amplifies the pair of differential modulated signals and generates a pair of differential radio frequency signals, accordingly.

Abstract: When transmitting an RF signal for power supply or a pulse signal for data transmission, amplification is made in such a manner that the peak power of the RF signal becomes greater than the peak power of the pulse signal. Thus transmitting the RF signal with the greater peak power enables charging of a capacitor 23 of noncontact wireless communication equipment 2 even if the distance to the noncontact wireless communication equipment 2 is long.

Abstract: A transmitter modulator that is operable to modulate signals according to multiple modulation formats includes a first modulator, a second modulator, and a polarization beam combiner. The first modulator encodes a first signal according to a first modulation format. The second modulator encodes a second signal according to a second modulation format, the first signal orthogonally polarized with respect to the second signal. The polarization beam combiner combines the first signal and the second signal for transmission.

Abstract: A radio frequency power amplifier (RF PA) apparatus includes an RF PA and a waveform converter. The waveform converter is configured to receive a sinusoidal RF signal and generate a nonsinusoidal RF signal, which is used to drive an active device (e.g., a field effect transistor (FET) or bipolar junction transistor (BJT)) of the RF PA. The nonsinusoidal RF signal, which may comprise a square wave or a substantially-square wave signal, has signal characteristics that result in less leakage through the active device's input-output parasitic capacitance, compared to the leakage that would result if the sinusoidal RF signal was used to drive the active device. The leakage control methods and apparatus of the present invention may be advantageously employed in a variety of applications including, for example, RF polar transmitters.

Abstract: A method and device for the simultaneous compensation of several signal errors that occur in an IQ-modulator, using respective inverse correction signals, wherein the optimized signal magnitude of each correction signal is calculated by the determination of the effective signal error and by the subsequent iterative minimization of the effective signal error.

Abstract: To reduce the crest factor of a total signal, the signal dynamic range is corrected in baseband upstream of the interpolation filters. To this end, provision is made for the input of a correction device to be coupled to at least two signal sources which are designed to provide digital signals on different frequency bands. The correction device is designed to determine correction factors from the digital signals applied to the input and use them to alter the respective digital signals. The output of the correction device is coupled to a first and at least one second interpolation filter. This allows reduction of the signal dynamic range in baseband, which reduces the crest factor without having to accept substantial losses in signal quality.

Abstract: A wireless transmission system includes a wireless HDMI transmitter and a wireless HDMI receiver. The wireless HDMI transmitter includes a carrier oscillator provided for each channel of an HDMI transmission path to output a carrier signal in a millimeter band, an OOK modulator provided for each carrier oscillator to perform on-off keying modulation on a carrier signal outputted by its corresponding carrier oscillator, and an input circuit provided for each channel of the HDMI transmission path to input a digital signal outputted by a source device to the OOK modulator. Radio signals have different planes of polarization from their adjacent channels.

Abstract: A system and method to be used with first and second devices where the first and second devices are capable of communicating using a subset of different modulation schemes wherein the subset includes at least first and second different modulation schemes, the method for optimizing transmission of data from the first device to the second device, the method comprising the acts of at the first device, when data is to be transmitted from the first device to the second device, receiving at least a portion of a trigger signal from the second device wherein the transmitted trigger signal includes data transmitted using a sequence of at least two of the modulation schemes from the subset, the portion of the trigger signal received being a received trigger signal, analyzing the received trigger signal to identify one of the modulation schemes from the subset as a function of the received trigger signal as an initial modulation scheme to be used to transmit data to the second device and transmitting the data from the f

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: 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: A first header-attaching unit attaches to data of a low speed bit rate A, a header of the bit rate A. A second header-attaching unit attaches the header of the bit rate A to data of a high speed bit rate B. A combining unit combines outputs of the first and the second header-attaching units. A low speed scrambling unit performs a scrambling process on combined data by using a clock corresponding to the bit rate A. A high speed scrambling unit performs a scrambling process on the data of the bit rate B by using a clock corresponding to the bit rate B. During a timing corresponding to the bit rate A in the frame, a selector selects an output of the low speed scrambling unit. During a timing corresponding to the bit rate B in the frame, the selector selects an output of the high speed scrambling unit.

Abstract: This disclosure relates systems and methods for a high bandwidth modulation and transmission of communication signals.

Abstract: In particular embodiments, an error correction during the transmission of the data word is made possible through the change of the modulation state at pre-defined time points.

Abstract: A power transmitting apparatus is usable for wireless power and data transmission. The power transmitting apparatus includes a power transmitting section configured to transmit power and data to be transmitted as being converted into a pulse train; and a control section configured to control the power transmitting section such that a change of the power caused by superimposition of the data is decreased.

Abstract: A radio transmission apparatus has a first duty adjustment circuit which changes a duty ratio of a clock signal, a second duty adjustment circuit which changes the duty ratio of the clock signal to a duty ratio different from the duty ratio of the clock signal changed by the first duty adjustment circuit, a first AND circuit which takes a logical product between a data signal and the clock signal having passed through the first duty adjustment circuit, and a second AND circuit which takes a logical product between an output signal of the first AND circuit and the clock signal having passed through inversion of the output of the second duty adjustment circuit to generate a pulse signal.

Abstract: Data multiplexing subcarrier identification signal generating means generates a data multiplexing subcarrier identification signal that identifies subcarriers with which data signals are to be multiplexed. Transmission signal generating means generates transmission signals by multiplexing data signals with subcarriers according to the data multiplexing subcarrier identification signal.

Abstract: Methods and apparatus for reducing high-frequency events in polar domain signals. An exemplary method includes first generating an unmodified rectangular-coordinate signal having in-phase (I) and quadrature phase (Q) components that are modulated according to a predetermined modulation scheme. Next a first sample of the unmodified rectangular-coordinate signal is modified based on how close the first sample is to the origin in the complex signal plane and how fast a signal trajectory between the first sample and a subsequent sample changes. Finally, the modified rectangular-coordinate signal is converted to a polar domain signal having amplitude and phase components. By modifying the first sample in this manner, either or both the amplitude and phase components have reduced high-frequency content compared to a polar domain signal that would be generated without the first sample having been first modified.

Abstract: An adaptive differential pulse-code modulation-demodulation system and method thereof is provided. The method includes steps of modulating an analog audio input signal into a data packet, including a plurality of digital data through adaptive differential pulse-code modulation, an initial value and a scale factor associated with the digital data, to be sent to the communication network, and demodulating the data packet according to the digital data, the initial value and the scale factor, thereby reconstructing the data packet to an analog audio output signal.

Abstract: The invention is a method of transmitting a radio signal using a complex envelope elimination and restoration technique. The method includes receiving a radio frequency (RF) signal. Further, the method includes separating the RF signal into an in-phase baseband signal (I) and a quadrature baseband signal (Q). Still further, the method includes decomposing the (I) signal into a in-phase magnitude component and a in-phase phase component while decomposing the Q signal into a quadrature magnitude component and a quadrature phase component. Alternatively, the source signal could be digital baseband information. Digital signal processing could generate the phase and magnitude reference signals for the system.

Abstract: A nonlinear filter includes: a determination unit that determines, based on I and Q signals inputted into the determination unit, whether or not to perform pulse insertion; a rotation detector that detects a rotation direction of the I and Q signals on an IQ plane with respect to the origin of the IQ plane; a pulse generator that generates, when the determination unit determines to perform the pulse insertion, a pulse of which at least one of the direction and the magnitude is determined in accordance with at least the detected rotation direction; and an adder that inserts the pulse into the I and Q signals and outputs resultant I and Q signals.

Abstract: Techniques for producing an output signal using an outphasing transmitter are disclosed. In some examples, constant modulation (CM) signals may be produced from a digital input signal. The CM signals may be converted to an analog state and filtered. The signals may then be modulated to produce modulated signals, which may be amplified. The amplified signals may be combined to produce combined signals, which may further be combined to produce an output signal.

Abstract: Compact pulse shape partial response (CPS PR) signaling is developed for trellis based signals like QM-MSK, and for PAM/QAM type signals to improve the performance to bandwidth tradeoff. Compact pulse shaped signals are partial response signals that employ a very short pulse shaping filter and use Viterbi decoding to optimally detect the CPS signal in presence of its inherent inter-symbol interference. The CPS filters considered herein have much shorter impulse response than the well-known raised cosine (RC) filter. There is no need to equalize the received signal to eliminate ISI or to allow a fixed amount of ISI between received signal samples as sampled at the symbol rate as is common in partial response maximum likelihood (PRML) systems. Numerical results indicate that CPS QM-MSK and CPS QAM provides between several dB of gain, depending on constellation size, over PR-CPM and RC QAM, when compared at a given value of bandwidth, i.e., B99Tb.

Abstract: An amplitude modulated pulse transmitter designed to operate across a multi MHz range of modulation frequencies. A wire wound rare earth magnet is to be utilized instead of the typical modulation transformer. Additionally, a plurality of electrolytic capacitors are also employed in the transmitter.

Abstract: A power tuning method determines values of a magnitude control signal that controls the magnitude of an amplitude-modulated power supply signal applied to a power supply port of a power amplifier of a polar transmitter and an amplitude control signal that controls the amplitude of a constant-envelope phase-modulated signal applied to a radio frequency input port of the power amplifier necessary to set the output power of the polar transmitter to a target output power. The method is repeated and performed for a plurality of different target output powers. Output-power-level dependent power control parameters calculated from the applied method are used to set the values of the magnitude control and amplitude control signals during normal operation.

Abstract: A wireless short range transmission system comprises a controller, a first oscillator, a transmitter, and an antenna. The transmitter comprises a phase-lock loop frequency synthesizer for receiving a reference signal from the first oscillator and a first modulation signal. The phase-lock loop frequency synthesizer is configured to be turned on by the first modulation signal for generating a carrier signal based on the reference signal. The transmitter further comprises a power amplifier for receiving the carrier signal from the phase-lock loop frequency synthesizer and a second modulation signal. The power amplifier is configured to be turned on/off by the second modulation signal to generate a modulated signal based on the carrier signal. The power amplifier is turned on after the phase-lock loop frequency synthesizer is stabilized and the phase-lock loop frequency synthesizer is turned off with the power amplifier or after the power amplifier has been turned off.

Abstract: A coding unit for determining two different types of modulation to be applied to two carrier signals such that each modulated carrier signal represents a data symbol in accordance with a group of modulation points, each modulation point representing a modulation of the first type and a modulation of the second type that can be applied to one of the carrier signals, the coding unit being arranged to associate the data symbol with a first one of the modulation points by applying a first mapping function to that data symbol and associate the data symbol with a second one of the modulation points by applying a second mapping function to that data symbol, the first and second mapping functions being such that they each map two different data symbols to a respective common modulation point; and determine the modulation of the first and second types to be applied to the first carrier signal to be the modulation of the first and second types represented by the first modulation point and the modulation of the first an