Multiphase signal generation circuitry receives input signals that are out-of-phase with one another by a quadrature delay (e.g., 90°), and generates output signals that are out-of-phase with one another by half of the quadrature delay. A first input signal may be provided to a first delay circuitry, which is then input to a first phase interpolator. The first delay circuitry is also input to second delay circuitry, which also generates an output that is input to the first phase interpolator. The first phase interpolator outputs a first output signal. The second delay circuitry is input to third delay circuitry, which in turn is input to a second phase interpolator with a second input signal that is out-of-phase with the first input signal by the quadrature delay. The second phase interpolator outputs a second output signal that is out-of-phase with the first output signal by the half of the quadrature delay.

Multiphase signal generation circuitry receives input signals that are out-of-phase with one another by a quadrature delay (e.g., 90°), and generates output signals that are out-of-phase with one another by half of the quadrature delay. A first input signal may be provided to a first delay circuitry, which is then input to a first phase interpolator. The first delay circuitry is also input to second delay circuitry, which also generates an output that is input to the first phase interpolator. The first phase interpolator outputs a first output signal. The second delay circuitry is input to third delay circuitry, which in turn is input to a second phase interpolator with a second input signal that is out-of-phase with the first input signal by the quadrature delay. The second phase interpolator outputs a second output signal that is out-of-phase with the first output signal by the half of the quadrature delay.

A method and apparatus for decomposition of signals with varying envelope into offset components are disclosed here, that sample the time variant envelope of a single carrier (SC) or a multi-carrier (MC) band limited signal, quantizes the sampled value using N.sub.b quantization bits and decomposes the sample into N.sub.b in-phase and quadrature components that are combined in pairs and modulated to generate a set of N.sub.b offset signals. The pulse shape applied in each offset signal is selected according to the spectral mask needed for the signal and to minimize envelope fluctuations in each offset signal from the set of N.sub.b components.

A quadrature detection unit subjects an FM signal to quadrature detection using a local oscillation signal and outputs a base band signal. A first correction unit and a second correction unit correct the base band signal using a DC offset correction value. A DC offset detection unit subjects the corrected base band signal to rectangular to polar conversion and derives the DC offset correction value such that amplitudes in a plurality of phase domains defined in an IQ plane approximate each other. An FM detection unit subjects the corrected base band signal to FM detection and generates a detection signal. An addition unit adds an offset to the detection signal. An AFC unit generates a control signal for controlling a frequency of a local oscillation signal based on the detection signal to which the offset is added.

Systems and methods are directed to low cost and low power carrier frequency offset (CFO) estimation in a receiver. In-phase (I) and quadrature (Q) samples of a wireless signal are received by the receiver and a first phase and a second phase are extracted from the outputs of a first autocorrelator with a first time-lag and a second autocorrelator with a second time-lag. The extracted first and second phases are combined to generate an estimated CFO of high accuracy and wide estimation range.

A digital radio receiver adapted to receive radio signals modulated using continuous phase frequency shift keying, CPFSK. The receiver comprises means for receiving a radio signal (2), a correlator (8) arranged to estimate a frequency offset between the carrier frequency of the received radio signal and a nominal carrier frequency, means for correcting said frequency offset (4) and outputting a frequency-corrected radio signal (6), and a matched filter bank, MFB, which comprises a plurality of filters (20,22), each of which corresponds to a different bit pattern, for determining a bit sequence (36) from the frequency-corrected radio signal (6).

A method and system of transmitting data. The method comprises receiving data, in a memory of the server computing device, from an asset tracker device; determining, in a processor of the server computing device, one or more weighting factors representing a respective priority associated with one or more of a latency, a cost, a power utilization and a throughput associated with transmission of the data for each of a plurality of communication channels; and selecting, from the plurality of communication channels, a communication channel for transmission of the data based at least in part on the one or more weighting factors and a transmission schedule for the data.

A wireless transceiver system includes a transmitter and a receiver. The transmitter includes a digital processor and a self-correction modulator coupled to the digital processor, wherein based upon a calibration correction assessment of an in-phase (I) signal and a quadrature (Q) signal received from the digital processor, the self-correction modulator generates a calibrated modulated signal. The self-correction modulator includes a core modulator and a calibration correction unit. The calibration correction unit is configured to correct an output of the core modulator based upon the calibration correction assessment. The calibration correction unit includes a calibration processing unit and a calibration modulator, wherein the calibration processing unit provides correction quantities that are used to program the calibration modulator to provide the self-corrected modulated signal.

A demodulation system for demodulating an input signal is provided. The input signal includes a carrier wave modulated with data symbols selected from a plurality of candidate complex symbol values. The system includes a carrier recovery module, operative to compensate for a carrier frequency of the carrier wave and output a demodulated data signal. The carrier recovery module includes: a first complex-signal conversion module, operative to convert the input signal into a complex-valued input signal; a voltage-controlled oscillator; a mixer, for mixing the complex-valued input signal and a complex-valued output signal of the voltage-controlled oscillator, and generating a mixer output signal; a low-pass filter, coupled to the mixer, operative to filter the carrier frequency from the mixer output signal, and output a signal corresponding to the demodulated data signal; and a folding module, operative to apply a folding algorithm to the output signal of the low-pass filter.

Clustering-based methods, apparatuses for frequency offset determination and elimination and electronic devices are disclosed. The clustering-based method for frequency offset determination includes: determining a constellation diagram for a received signal; determining N different values within a preset frequency interval, as N frequency offset estimates for a frequency offset of the received signal; for each of the frequency offset estimates, correcting the constellation diagram based on the frequency offset estimate to obtain a corrected constellation diagram, clustering signal points on the corrected constellation diagram, and calculating an area of a signal region in the corrected constellation diagram after clustering; and determining a frequency offset estimate corresponding to a signal region with a minimum area as a value of the frequency offset. The embodiments of the present invention can improve the accuracy and stability of the calculated value of the frequency offset.