Abstract: The invention relates to methods for transmitting and receiving a data bit stream in a communication system using a 16-QAM constellation. Further, an apparatus for performing the methods is provided. To provide a modulation and coding scheme using a signal space expansion and 16-QAM which improves the bit-error rate in comparison to QPSK modulated signals and still provides the possibility to implement coders and decoders with low complexity the invention suggests the use a 16-QAM constellation with specially selected mapping rules together with repetition coding (signal space expansion) and interleaving of the data stream to be transmitted.

Abstract: The invention relates to methods for transmitting and receiving a data bit stream in a communication system using 16-QAM constellations. Further, an apparatus for performing the methods is provided. To improve the bit-error rate performance of the communication using the 16-QAM constellations the invention suggests the use 16-QAM constellations with specially selected mapping rules together with a special constellation rearrangement for creating different versions of the 16-QAM constellations. Further, the data stream is transmitted according to a diversity scheme employing different versions of the 16-QAM constellations obtained adhering the mapping rules and rearrangement rules defined by the invention.

Abstract: A partial bit demodulation section that demodulates partial bits among a plurality of bits that form 1 symbol of each modulated signal using a detection method different from likelihood detection, signal point reduction sections that reduce the number of candidate signal points using demodulated partial bits, and a likelihood detection section obtains received digital signals by performing likelihood detection based on the Euclidian distances between the reduced candidate signal points and a reception point, are provided. By this, only some bits which are unlikely to be erroneous are found by the partial bit demodulation section, and other bits can be found by the likelihood detection section, enabling bit error rate performances to be effectively improved with a comparatively small computational complexity.

Abstract: In a semiconductor integrated circuit, a switching circuit controls the capacity of a capacitor unit based on a control signal from a control circuit and separates a resonant frequency determined by first inductance, second inductance, and the capacity of the capacitor unit from the band area of the signal handled by an A/D converter.

Abstract: An approach is provided for supporting signal acquisition and frame synchronization in a digital broadcast system utilizing Low Density Parity Check (LDPC) codes. Hierarchical modulation is utilized to provide backward compatibility, whereby the lower layer signal is encoded using LDPC coding. A signal is received, whereby the signal is modulated according to the hierarchical modulation scheme including an upper layer and a lower layer. The signal includes a data pattern and a coded frame. The dependency of the received signal on the upper layer modulation is removed. The modulation removed signal is correlated with multiple predetermined data patterns to determine the data pattern of the signal. The code rate of the coded frame is derived based on the determined data pattern. The above arrangement is particularly suited to a digital satellite broadcast system.

Abstract: A system and device communicates data. A modulation and mapping circuit modulates and maps data symbols into a plurality of multiple subcarriers that are orthogonal to each other based on a fixed or variable symbol rate. A frequency domain spreader circuit is operatively connected to the modulation and mapping circuit and spreads the multiple subcarriers over the frequency domain.

Abstract: The invention relates to signal transmitting engineering. The use of the inventive method in systems for transmitting and receiving quadrature amplitude-modulation signals (QAM) exhibiting a low carrier frequency synchronization threshold makes it possible to decrease a demodulation threshold by means of said low carrier frequency synchronization threshold. The result is attainable by supplementing a burst of M m-level sensitive QAM symbols by predetermined symbols, one part of which remains constant form one burst to another and the other part is periodically invertible in certain bursts, thereby the QAM signal components corresponding to the additional predetermined symbols (whose frequencies are known) are extracted on a receiving side. The inversion frequency is determined according to said components, thereby making it possible to eliminate the ambiguity of the receiving frequency synchronization control and to approach the Shannon's threshold.

Abstract: A programmable hybrid transmit baseband module includes a wireless protocol conversion module, a set of modules, and a mode select module. The wireless protocol conversion module is operable to convert outbound data into a complex signal having an in-phase (I) signal component and a quadrature (Q) signal component. The set of modules is operable to generate an offset adjusted normalized I signal component, an offset adjusted normalized Q signal component, and corrected amplitude modulation data, wherein each of the normalized I and Q signal components includes phase modulation data. The mode selection module is operable to output the I and Q signal components when the programmable hybrid transmit baseband module is in a first mode; and output the offset adjusted normalized I and Q signal components and the corrected amplitude modulation data when the programmable hybrid transmit baseband module is in a second mode.

Abstract: A vestigial sideband (VSB) modulation transmission system and a method for encoding an input signal in the system are disclosed. According to the present invention, the VSB transmission system includes a convolutional encoder for encoding an input signal, a trellis-coded modulation (TCM) encoder for encoding the convolutionally encoded signal, and a signal mapper mapping the trellis-coded signal to generate a corresponding output signal. Different types of the convolutional encoders are explored, and the experimental results showing the performances of the VSB systems incorporating each type of encoders reveals that a reliable data transmission can be achieved even at a lower input signal to noise ratio when a convolutional encoder is used as an error-correcting encoder in a VSB system.

Abstract: A data transportation/reception apparatus and method in a mobile communication system. The data transportation apparatus and method divides transport data bits into bits having higher priority and bits having lower priority, maps the bits having higher priority to bit positions having higher reliability, and maps the bits having lower priority to bit positions having lower reliability. The data reception apparatus and method demodulates received modulated symbols, divides the demodulated coded bits into two coded bit groups according to priority, deinterleaving the coded bit groups using different deinterleavers, and decodes the deinterleaved coded bits.

Abstract: During operation of a transmitter a circular buffer is created where only column tops of the circular buffer are defined as a starting position for a redundancy version. Where the circular buffer is in sequence format, all possible redundancy versions are at positions ?Kstream/32?(12×i+?), i=0, 1, . . . , 7 where ? indicates the column index of the starting position of the first RV (RV0).

Abstract: A transmitter, a receiver, and a transceiver for use in a wireless communication system are disclosed. In one embodiment, the radio frequency (RF) transmitter comprises a first parallel-to-serial converter to convert first parallel data corresponding to a I quadrature baseband signal component into a first set of serial data bits, a second parallel-to-serial converter to convert second parallel data corresponding to a Q quadrature baseband signal component into a second set of serial data bits, and one or more stages having a first XOR gate coupled to a gate terminal of a first transistor and a second XOR gate coupled to a gate terminal of second transistor. The first XOR gate has a pair of inputs coupled to the first set of serial data bits and a first clock (e.g.

Abstract: A method of providing a multi-resolution transmission with a MIMO scheme may include employing a selected modulation scheme to generate a first data stream including basic information and a second data stream including both enhanced information and the basic information, and employing a modulation and multiple input/multiple output (MIMO) scheme to generate data for transmission. The data for transmission may employ a combination of spatial multiplexing and transmit diversity techniques. A corresponding apparatus is also provided. Another method of providing selective recovery of received data at a mobile terminal may include receiving data at a mobile terminal including at least one antenna, receiving information indicative of a data reception condition at the mobile terminal, determining, between spatial multiplexing and transmit diversity mode options, a reception mode to be employed for decoding the data received based on the information indicative of the data reception condition.

Abstract: A differential positive coefficient weighted quadrature modulator is actuated responsive to quadrature clock signals and positive digital modulation signals input to the modulator. The modulator includes an I-channel positive coefficient weighted modulator (PCWM) and a Q-channel PCWM. The I-channel PCWM has differential output nodes configured to output a differential I-channel signal responsive to the state of first and second positive digital modulation signals and first and second complimentary quadrature clock signals input to the I-channel PCWM. The Q-channel PCWM has differential output nodes configured to output a differential Q-channel signal responsive to the state of third and fourth positive digital modulation signals and third and fourth complimentary quadrature clock signals input to the Q-channel PCWM.

Abstract: A method is provided for transmitting a digital signal. The method includes generating a plurality of spatial streams from a digital signal and transforming the spatial streams into a plurality of space-time streams. Each of the space-time streams are cycled in the frequency domain among each of a plurality of transmit antennas. The space-time streams are wirelessly transmitted from the plurality of transmit antennas.

Abstract: Provided is a transmission circuit which is small in size, operates with high efficiency, and outputs a transmission signal having high linearity. A signal generation section 11 generates an amplitude signal m(t) and a phase signal. An angle modulation section 17 angle-modulates the phase signal to output an angle-modulated signal. An amplitude calculation section 12 outputs a discrete value signal V(t) having a plurality of discrete values corresponding to a magnitude of the amplitude signal m(t). A dividing section 13 divides the amplitude signal m(t) by the discrete value signal V(t) to output an amplitude signal M(t). A delta-sigma modulation section 14 delta-sigma modulates the amplitude signal M(t) to output a delta-sigma modulated signal. A variable gain amplifier section 15 amplifies the delta-sigma modulated signal by a gain corresponding to the discrete value signal V(t).

Abstract: A method for transmitting data comprising a plurality of bits is described wherein the data is mapped to a plurality of modulation symbols, each modulation symbol comprising at least one more significant bit and at least one less significant bit, at least one parity bit is generated for the plurality of bits and the plurality of bits are mapped to more significant bits of the plurality of modulation symbols and the at least one parity bit is mapped to at least one less significant bit of the plurality of modulation symbols.

Abstract: In one embodiment, a circuit comprises a first pair of elements, a second pair of elements, a combiner, and a signal output. Each element in the first and second pair of elements comprises an amplitude-control input for receiving an amplitude-control bit, a phase-control input for receiving a phase-control bit, a signal input for receiving an input signal, a modulator for producing an output signal based on the amplitude-control bit, the phase-control bit, and the input signal, and an signal output for transmitting the output signal to the combiner. The combiner combines the two output signals from the first and second pair of elements to produce an output signal for the circuit to be transmitted by the signal output of the circuit.

Abstract: A method of broadcasting an AM compatible digital audio broadcasting signal includes: producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions including an upper main partition, a lower main partition, an upper backup partition and a lower backup partition, and a non-overlapping tertiary partition, and transmitting the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals. Transmitters that broadcast the signal and receivers that receive the signal, and the reception method are also included.

Abstract: A digital broadcast transmitter/receiver, and a signal processing method thereof, includes a randomizer randomizing a dual transport stream which includes a normal data packet and a robust data packet and into which stuff bytes are inserted, a stuff-byte exchanger replacing the stuff bytes of the randomized data with known data, a first RS encoder performing RS-encoding of data output from the stuff-byte exchanger, a packet formatter performing an interleaving of the robust packet of the data output from the first RS encoder and reformatting the packet, an interleaver interleaving data output from the packet formatter, a trellis encoder performing a trellis encoding of interleaved data, a second RS encoder changing a parity by performing an RS encoding of the robust data of the trellis-encoded data, and a modulator modulating data output from the trellis encoder and RF up-converting the modulated data.

Abstract: A transmission device includes an RQAM modulating unit that has an S/P that divides a transmitting signal indicating information to be transmitted into a first signal and a second signal, a mapping unit that maps the first signal into a first in-phase component and a second in-phase component and the second signal into a first orthogonal component and a second orthogonal component by a predetermined mapping system, a P/S that generates a first modulated signal including the first in-phase component and the first orthogonal component and a second modulated signal including the second in-phase component and the second orthogonal component, an IFFT that transmits the first modulated signal and the second modulated signal, a DAC, an LPF, a Mixer, a BPF, and a LOCAL.

Abstract: In RF transceivers, a method and system for a second order input intercept point (IIP2) correction are provided. A DC offset sensor may detect DC offset voltages produced by blocker signals in “I” and “Q” signal component paths in an RF receiver. The DC offset sensor may generate control signals which may be utilized by a first and second injection circuits to generate DC offset currents that compensate for the DC offset voltages in the signal component paths. An injection circuit may utilize current drivers to generate binary weighted currents which may be added together to produce a DC offset current. The polarity of the DC offset current and the selection of which current drivers to use may be determined by the control signals. A calibration voltage may also be utilized to correct or adjust the gain in the injection circuit.

Abstract: Disclose is a modulation method that transmits n bits per modulation symbol, comprising the steps of: (a) generating a constellation of which 2n constellation points are arranged to be angular point of equilateral triangle; (b) generating a modulation symbol by mapping the constellation point with digital signal. According to the present invention, average power consumed by constellation points can be reduced by using equilateral triangular constellation.

Abstract: A multi-mode communication device (100) uses a quadrature transmitter (102) for transmitting both amplitude and constant envelope angle-modulated signals. For angle modulation, a separate feedback path is used from that used for amplitude modulated signal transmission. An FM receiver (136) is used to produce error signals (214, 216) used in correcting the I and Q quadrature signals (206, 208).

Abstract: In accordance with some embodiments, a differential frame may be constructed, for example, by differencing frames or using an error prediction method. More frequently and less frequently used values of a differential frame are identified. Symbols with lower and higher transmission energy are identified. The more frequently used values of the differential frame are mapped to the symbols with lower transmission energy to reduce overall energy consumption.

Abstract: A system and method communicates and generates a Coded Orthogonal Frequency Division Multiplexed (COFDM) communications signal as a plurality of subcarriers. Selected subcarriers are turned ON and OFF while also frequency hopping and spreading the selected ON subcarriers over the frequency domain based on a fixed or variable sample rate to reduce average power for enhanced Low Probability of Interception/Low Probability of Detection (LPI/LPD) and also allow for more transmit power within a spectral mask.

Abstract: The invention enables the transmission of continuous complex numbers using a symbol based transmission scheme such as OFDM. Accordingly, complex numbers are mapped to the constellation map, enabling a fine granularity of constellation points. This scheme may be used, for example, in the transmission of video where the coefficients representing the higher frequency of each of the video components, as well as the quantization error values of the DC and near DC components, or some, possibly non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a symbol.

Abstract: A transmitting apparatus comprising circuitry operable to generate a plurality of bit sequences using bits included in a first data block and a second data block, circuitry operable to control the plurality of bit sequences to correspond to a signal point on the phase plane, comprising a bit sequence generating unit operable to control the generation of the bit sequences to adjust an occupation rate occupied with predetermined bits included in the first data block to be closer to an occupation rate occupied with predetermined bits included in the second data block in regard to bit positions of the predetermined bits, based on an error tolerance of the respective bit sequences generated resulting from the correspondence to a signal point on the phase plane, and circuitry operable to transmit the signals obtained by multi-level modulations in accordance with each signal point.

Abstract: A novel framing method for a variable net bit rate digital communications system that utilizes a set of different QAM constellations and punctured trellis code combinations, each combination designated as a mode. This frame structure has a variable integral number of QAM symbols per frame depending on the selected mode, but the number of bytes and Reed-Solomon packets per frame is constant. This is achieved even though the number of data bits per QAM symbol for some modes is fractional. Also the number of trellis coder puncture pattern cycles per frame is an integer for all modes. This arrangement simplifies the synchronization of receiver processing blocks such as the Viterbi decoder, de-randomizer, byte de-interleaver, and Reed-Solomon decoder.

Abstract: Systems and methods for determining an unknown QPSK or QAM constellation from a set of possible received constellations are described. One method utilizes a histogram of the power of the signal after inter-symbol-interference has been minimized with a modified constant modulus algorithm equalizer. The constellation may be determined before carrier frequency and phase has been fully recovered. An unknown QPSK or QAM constellation may be identified before or after equalization using disclosed methods for analyzing an output power histogram.

Abstract: A baseband circuit for a communications transmitter includes a baseband modulator, a pulse-shaping filter, and an AMPR reduction circuit. The baseband modulator is configured to generate a sequence of symbols formatted in accordance with a non-constant envelope modulation scheme. The pulse-shaping filter is configured to band-limit the sequence of samples to provide a sequence of samples. The AMPR reduction circuit is configured to analyze and modify one or more samples in the sequence of samples, if a sample in the sequence of samples that has been previously analyzed by the AMPR reduction circuit is determined to have a magnitude less than a predetermined low-magnitude threshold.

Abstract: A system and method for real time calibration of a quadrature encoder. Errors from sources such as signal offsets, amplitude mismatches and phase errors are addressed. In one embodiment, the errors are addressed by determining and applying a dynamic operational set of calibration parameters. The process for determining the operational calibration parameters involves minimizing a variation metric that indicates the variations of the magnitudes of a set of corrected vectors Ci?. The corrected vectors Ci? are defined by using the calibration parameters to provide corrected vector components (Ati?, Bti?) that correspond to a current operational set of quadrature signal samples comprising at least four respective quadrature signal samples (Ati, Bti) having spatial phase angles ?ti that are distributed over a significant portion of 360 degrees. For well chosen calibration parameters, the resulting corrected vectors define a well-centered circle and the variation metric is minimized.

Abstract: A transmitter includes a first amplifier to amplify an in-phase oscillator signal to produce an in-phase mixing signal and a second amplifier to amplify a quadrature-phase oscillator signal to produce a quadrature-phase mixing signal. A first mixer mixes the in-phase mixing signal with a first information signal to produce a first output signal. A second mixer mixes the quadrature-phase mixing signal with a second information signal to produce a second output signal. The first output signal and an inverted second output signal are summed to produce a transmitter output signal that includes an image signal caused by a phase imbalance between the in-phase and quadrature-phase mixing signals. An image monitor monitors the image signal and reduces or eliminates the phase imbalance by independently adjusting a phase of the in-phase mixing signal and/or a phase of the quadrature-phase mixing signal. Consequently, a power of the image signal is reduced or eliminated.

Abstract: A distortion compensating apparatus has an IQ imbalance compensation coefficient arithmetic circuit 31 for calculating, from correlation values of a transmission signal and a feedback signal, IQ imbalance compensation coefficients for compensating for IQ imbalance in a quadrature modulator 23; and an IQ imbalance compensator 21 for compensating for the IQ imbalance with respect to a distortion compensated signal output from a distortion compensator 11 according to the IQ imbalance compensation coefficients, and for outputting to the quadrature demodulator 23.

Abstract: An exemplary embodiment of the present invention proposes a transmitter including a hierarchical modulator. The hierarchical modulator receives, jointed encodes, and maps a high-priority and low-priority bit-stream signals, so as to generate multiple mapping signal, wherein each mapping signal is the summation of a low-priority and high-priority mapping signals. The low-priority mapping signal is the complex number signal on the frequency domain to which part bits of the low-priority bit-stream signal are mapped, and the high-priority mapping signal is the complex number signal on the frequency domain to which part bits of the high-priority bit-stream signal are mapped. The pth low-priority mapping signal is related to (p+1)th low-priority mapping signal, and p is an even number or an odd number.

Abstract: A method and system for calibrating a quadrature modulator. The method includes: determining a set of sideband calibration frequencies; for each sideband calibration frequency out of the set of sideband calibration frequencies: inputting an input signal having the sideband calibration frequency to the quadrature modulator; measuring a sideband signal power level; determining at least one calibration parameter in response to phase and gain imbalances expected at the measured sideband signal power level.

Abstract: A method setting a maximum number of determinations for computing power allocation responsive to allocating power among multiple users in one subchannel of an OFDM system; beginning determination of maximum sum-throughput of users in the OFDM system with a randomly generated power profile with an iteration including: i) computing a sum-throughput using a power profile; ii) keeping a previous power profile if the sum-throughput of the current power profile sum-throughput is less than the previous power profile sum-throughput; iii) finding an index of power profile that has maximum sum-throughput; and ascertaining power profiles when the iteration is complete.

Abstract: Apparatus and methods for improving the performance of a modulator, typically in an I/Q modulation system, are described. Input I and Q current modulation signals may be processed to generate a sign signal and a magnitude signal, with the magnitude signal selectively applied to the inputs of a mixer based on the sign signal so as to generate respective I and Q modulation signal components. These may then be combined to generate a composite modulation signal.

Abstract: A method for transmitting and receiving a signal and an apparatus for transmitting and receiving a signal are disclosed. The method includes receiving the signal from a first frequency band in a signal frame including at least one frequency band, demodulating the received signal by an orthogonal frequency division multiplexing (OFDM) method and parsing the signal frame, acquiring a symbol stream of a service stream from the at least one frequency band included in the parsed signal frame, demapping symbols included in the symbol stream and outputting the demapped symbols to sub streams, multiplexing the output sub streams and outputting one bit stream, and deinterleaving and error-correction-decoding the output bit stream.

Abstract: A wireless multicarrier transmission method in which a multicarrier transmission uses n modulated frequency subcarriers (n is an integer number), and a fading condition of each subcarrier is detected to generate fading channel profile information.

Abstract: A method for transmitting signals using a hybrid automatic repeat request (HARQ) scheme to guarantee a constellation rearrangement gain having a predetermined level or more is provided. Predetermined code blocks are encoded, sub-block interleaving is performed with respect to the encoded code blocks, and the sub-block interleaved code blocks are transmitted according to redundancy version (RV) start locations of the sub-block interleaved code blocks. The RVs are set such that the order of bit streams modulated by an M-QAM (M>4) scheme is changed upon a retransmission. In addition, the RVs are set such that the RV start locations applied to code blocks having different sizes are different.

Abstract: The present invention provides a method to minimize degradation in a D-MPSK hierarchical modulation system by adding additional data throughput (i.e., secondary information) as an offset to the primary signal transmitted by a SDARS terrestrial repeater. The present invention provides techniques for adding the additional throughput as Level 2 data by transmitting offset phase and/or amplitude information across adjacent OFDM symbols and/or adjacent frequency subcarriers.

Abstract: Embodiments of methods, transceiver circuits, and systems can compensate an IQ mismatch (e.g., Tx or Rx) or a carrier leakage using a plurality of local oscillators. One embodiment of a transceiver can include a first up-conversion IQ mixer, a second up-conversion IQ mixer, a first down-conversion IQ mixer with an input to receive an output of the second up-conversion IQ mixer, a second down-conversion IQ mixer with an input to receive an output of the first up-conversion IQ mixer, a first local oscillator to generate a first IQ LO signal for the first up-conversion IQ mixer and the first down-conversion IQ mixer, and a second local oscillator to generate a second IQ LO signal for the second up-conversion IQ mixer and the second down-conversion IQ mixer.

Abstract: An apparatus and associated methods for performing space-frequency interleaving in a multicarrier wireless communication system is generally described.

Abstract: A method of transmitting data including 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, to be closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data. With regard to first bit positions of the predetermined bits, the first bit positions being distinguished from second bit positions based on an error tolerance resulting from a correspondence to a signal point on a phase plane. Wherein a sum of a number of the predetermined bits included in the first data block and the predetermined bits included in the second data block is less than a total number of the first bit positions. Also including performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: Method and apparatus for signal processing to minimize the peak to average power ratio of an Orthogonal Frequency Division Multiplexing (“OFDM”) or Orthogonal Frequency Division Multiple Access (“OFDMA”) signal with bounded error vector magnitude for an integrated circuit are described. An Active Constellation Extension (“ACE”) iteration, using a constellation points adjustment module, is performed. Symbols outside of a bounded region after the ACE iteration are identified. The bounded region is determined responsive to an error vector magnitude target. The symbols identified are translated to the bounded region.

Abstract: A radio communication apparatus that is capable of switching modulation schemes. The radio communication apparatus includes a QPSK modulation signal generator, a QAM modulation signal generator, a transmission radio, and a common transmission power amplifier. The QPSK modulation signal generator modulates transmission data by a QPSK modulation scheme and outputs a QPSK modulation signal. The QAM modulation signal generator modulates transmission data by a QAM scheme and outputs a QAM modulation signal. The transmission radio receives the QPSK modulation signal or the QAM modulation signal and outputs a transmission signal, which is amplified by the common transmission power amplifier.

Abstract: A novel apparatus for and method of delay alignment between amplitude and phase/frequency modulation paths in a digital polar transmitter. The invention provides a fully digital delay alignment mechanism where better than nanosecond alignment is achieved by accounting for processing delays in the digital circuit modules of the transmitter and by the use of programmable delay elements spread across several clock domains. Tapped delay lines compensate for propagation and settling delays in analog elements such as the DCO, dividers, quad switch, buffers, level shifters and digital pre-power amplifier (DPA). A signal correlative mechanism is provided whereby data from the amplitude and phase/frequency modulation paths to be matched is first interpolated and then cross-correlated to achieve accuracy better than the clock domain of comparison.

Abstract: A method and apparatus for compensating for a mismatch in a radio frequency (RF) quadrature transceiver using a direct-conversion scheme is provided. The method includes setting an amplification gain for a baseband quadrature signal to be larger than an amplification gain for a baseband in-phase signal in a reception module; receiving only a baseband in-phase signal in a transmission module; and compensating for a phase mismatch on a basis of a signal output from a quadrature output port. The apparatus includes a phase mismatch compensator which sets an amplification gain for a baseband quadrature signal to be larger than an amplification gain for a baseband in-phase signal in a reception module, inputs only a baseband in-phase signal to a transmission module, and compensates for a phase mismatch on a basis of a signal output from a quadrature output port.

Abstract: A radio frequency transmitter, of the type supplied with two signals in baseband and in quadrature, I(nT) and q(nT), which are images from two binary streams representing information to be transmitted, 1) provides a first transposition into the digital domain, at an intermediate frequency ?0, for the baseband signals and generates, by combination, two signals of intermediate frequency in quadrature, 2) provides a second transposition into the analog domain, after multiplication by a frequency ?1, followed by a summation of the two signals at intermediate frequency and in quadrature, in such a way that a resultant signal is generated which is found finally around a frequency ?2, where ?2=?0+?1. In an advantageous variant, the radio frequency transmitter additionally digitally compensates gain and phase imperfections of the direct conversion.