A polar transmitter provided for transmitting a phase/frequency modulated and amplitude modulated transmit signal and a method for generating a transmit signal using a polar transmitter are described. An example polar transmitter comprises a phase locked loop for generating a phase/frequency modulated precursor of the transmit signal. The phase locked loop comprises at its input a phase error detection unit for detecting a phase error of the precursor fed back from the output of the phase locked loop to the phase error detection unit as a feedback signal. The polar transmitter comprises a digital amplitude modulator for amplitude modulation of the precursor, resulting in the transmit signal. The digital amplitude modulator is arranged within the phase locked loop for amplitude modulation of the precursor before being output by the PLL. The phase error detection unit is further provided for detecting the amplitude of the feedback signal.

A gear shifting technique has been developed in which modulation and equalization are shifted to achieve optional performance. In one form, two or more equalizers, each associated with a demodulator and message decoder, determine if the modulation being used can be increased in complexity in order to increase the channel throughput or determine if the modulation method should be reduced in complexity in order to improve the receiver error performance. The quality metrics can based on which equalizer-demodulator-decoder is set to first detect a valid message. Other factors can be considered with this technique such as a packet-error ratio and a signal-to-noise ratio. In a financial trading system, message erasures can be favored over errored messages by limiting the number of bit or symbol corrections permitted per message to less than the maximum possible for the selected decoding schemes.

Transmitters and methods of transmitting a polar-modulated signal include a driver to output a polar-modulated signal according to a phase-modulation signal and an amplitude-modulation signal. A voltage regulator is connected to the driver, with the amplitude-modulation signal controlling an input of the voltage regulator and with the amplitude-modulation signal further being combined with an output of the voltage regulator to control an amplitude of the output of the driver to compensate for bandwidth cutoff noise in the voltage regulator.

A method of transmitting, by a transmitting device, an orthogonal frequency division multiplexing (OFDM) signal in a wireless communication system, the method including: generating, by a digital module of the transmitting device, a frequency-shifted OFDM baseband signal by performing frequency up-shift of a first signal by a difference between a carrier frequency f.sub.0 and a first frequency f.sub.base, wherein the first frequency f.sub.base is, among frequencies corresponding to integer multiples of 128Δf, closest to the carrier frequency f.sub.0, and wherein Δf is an OFDM subcarrier spacing; up-converting, by an analog oscillator of the transmitting device, the frequency-shifted OFDM baseband signal by the first frequency f.sub.base to generate an OFDM symbol signal at the carrier frequency f.sub.0; and transmitting the OFDM symbol signal at the carrier frequency f.sub.0.

A transmitter includes: a modulation circuit that modulates a data sequence using QAM by mapping the data sequence to only four symbols each of which differs in phase by 90 degrees from an adjacent one of the four symbols and at least two of which have different amplitudes; and a transmission circuit that wirelessly transmits the data sequence mapped to the four symbols through the modulation by the modulation circuit, by assigning the data sequence mapped to the four symbols through the modulation by the modulation circuit to different subcarriers for Orthogonal Frequency Division Multiplexing (OFDM).

The disclosure provides a method for measuring a power of a non-constant envelope modulated signal, an electronic device, and a computer readable storage medium. The method includes: sampling baseband I/Q data transmitted by a device under test to obtain sample data, in which a sampling duration is less than a length of a cycle of the non-constant envelope modulated signal; calculating a sample power within the sampling duration based on the sample data; matching in predetermined baseband I/Q data in the cycle based on the sample data to obtain a target baseband I/Q data segment; obtaining a power calibration value corresponding to the target baseband I/Q data segment; and obtaining an actual power of the non-constant envelope modulated signal in the cycle based on the power calibration value corresponding to the target baseband I/Q data segment and the sample power within the sampling duration.

Architectures for inter-converting bitstreams and symbol streams of PAM and/or QAM constellations of different sizes that are not base-2 integers. Some of such constellations may be Gray-coded, and the constellation mapping may be performed to achieve an equiprobable distribution of different constellation symbols. Some embodiments may be compatible with FEC schemes. In an example embodiment, a transmitter DSP may employ a conventional constellation mapper preceded by an electronic encoder programmed to exclude some constellation-symbol labels from the bitstream applied to the mapper. In different embodiments, the electronic encoder may employ a CCDM and/or a long-division operation to select some amplitudes of the constellation and to exclude others. At least some embodiments are beneficially capable of achieving a smaller gap to the Shannon limit than comparable conventional solutions.

A transceiver includes a transmitter up-converting a frequency of input data to transmit data of a first frequency, an orthogonal basis generator receiving the input data from the transmitter to generate an orthogonal basis; and a receiver receiving the orthogonal basis from the orthogonal basis generator and receiving the transmitted data for down-converting a frequency of the received data to a second frequency different from the first frequency. The orthogonal basis generator includes, a multiplier multiplying the input data by a Gaussian characteristic value obtained by extracting a Gaussian characteristic of the data to generate an out of band emission (OOBE) value, and a polynomial block generating the orthogonal basis by using the OOBE value as an input to an Itô-Hermite polynomial.

A method to generate a wireless waveform for use in a wireless communication system, a wireless communication system and computer program product thereof

The method comprises the generation of a waveform for application in the wireless communication system characterized by significant phase noise, Doppler spread, multipath, frequency instability, and/or low power efficiency by at the transmitter side: creating a discrete-time instantaneous frequency signal {tilde over (f)}[n]; appending a cyclic prefix with length L.sub.CP to the beginning of the discrete-time instantaneous frequency signal {tilde over (f)}[n]; constructing a discrete-time unwrapped instantaneous phase φ[n]; constructing a discrete-time complex baseband signal, and appending at the beginning a Constant Amplitude Zero Autocorrelation, CAZAC, signal of length L.sub.CP for multipath detection; and passing the constructed discrete-time complex baseband signal through a digital-to-analog, DAC, converter to yield the continuous-time radio frequency signal s(t) after conversion to the carrier frequency.

The invention discloses a transmitter comprising a pulse encoder for creating pulses from the amplitude of an input signal to the transmitter, a compensation signal generator for cancelling quantization noise caused by the pulse encoder, a mixer or I/Q modulator for mixing an output of the pulse encoder with the phase of an input signal to the transmitter, said output of the pulse encoder comprising the amplitude of the complex input signal plus the quantization noise caused by the pulse encoder, and an amplifier for creating an output signal from the transmitter. In the transmitter, a control signal (C.sub.A) for controlling a function of the amplifier comprises an output signal from the compensation signal generator, and an input signal to the amplifier comprises an output from the mixer having been modulated to a desired frequency.