Abstract: An iterative method for synthesizing digital filters comprises the following steps: generation of a transmit filter intended to be applied to a signal to be transmitted; and generation of a receive filter intended to be applied to a received signal. The method comprises the following iteratively executed steps: convolution of the transmit filter and the receive filter in order to generate a transmission filter; determination of a criterion that is representative of the level of intersymbol interference on said transmission filter and whether the level of intersymbol interference is higher than a given level; calculation of an equalizing filter for the intersymbol interference; replacement of the transmit filter with the convoluted transmit filter having the equalizing filter or the replacement of the receive filter with the convoluted receive filter having the equalizing filter.

Abstract: A method of calibrating parameters for a polar transmitter (Polar TX) system includes receiving phase information derived from transmission information in a Polar TX for producing a radio frequency (RF) broadcast signal. An Inphase local oscillator (LO_I) signal and a quadrature phase local oscillator (LO_Q) signal are derived from a combination of a first signal and the phase information using a digital phase lock loop. A feedback receiver (FBR) receives the RF broadcast signal provided by the Polar TX. The LO_I signal and the LO_Q signal are mixed with the RF broadcast signal to obtain mixer output signals. RF path delay and IQ phase imbalance are concurrently determined as a function of the first signal and of the mixer output signals.

Abstract: Systems and methods for removing DC offset from a signal are provided. A radio frequency signal is received at a receiver. The radio frequency signal is converted into a digital signal including a periodic component with a period. A carrier frequency offset is removed from the digital signal to generate a frequency-shifted digital signal. The frequency-shifted digital signal is filtered to remove a DC offset in the digital signal. The filtering includes applying a moving average filter matched to the period to remove the periodic component from the frequency-shifted digital signal. The moving average filter generates a set of average values based on the frequency-shifted digital signal. The filtering also includes taking a difference between consecutive values of the set of average values to determine the DC offset, where the DC offset is introduced at the receiver.

Abstract: A receiver (100) is provided for signals of different signal strengths and modulated with respective pseudorandom noise (PN) codes. The receiver (100) includes a correlator circuit (120) operable to correlate the signals with a selectable locally-issued PN code having a Doppler and a code lag to produce a peak, the correlator circuit (120) being subject to cross correlation with a distinct PN code carried by least one of the signals that can produce cross correlation; and a cross correlation circuit (370, 400) operable to generate a variable comparison value related to the cross correlation as a function of values representing a Doppler difference and a code lag difference between the locally-issued PN code and the distinct PN code, and to use the variable comparison value to reject the peak as invalid from cross correlation or to pass the peak as a valid received peak.

Abstract: A communication system that uses keyed modulation to encode fixed frequency communications on a variable frequency power transmission signal in which a single communication bit is represented by a plurality of modulations. To provide a fixed communication rate, the number of modulations associated with each bit is dynamic varying as a function of the ratio of the communication frequency to the carrier signal frequency. In one embodiment, the present invention provides dynamic phase-shift-keyed modulation in which communications are generated by toggling a load at a rate that is a fraction of the power transfer frequency. In another embodiment, the present invention provides communication by toggling a load in the communication transmitter at a rate that is phase locked and at a harmonic of the power transfer frequency. In yet another embodiment, the present invention provides frequency-shift-keyed modulation, including, for example, modulation at one of two different frequencies.

Abstract: An exemplary method is implemented by a radio frequency receiver for synchronizing the recovery of data carried by frames. An indication is generated from error correction of whether the error control coding in the receiver is capable of correcting all the errors induced by the channel within the frame. If the indication declares that all the errors are corrected, then the carrier frequency estimate associated with the error free frame is saved in memory and will be used to initialize the carrier recovery loop at the beginning of the following frames until such frequency estimate is declared unreliable. A new carrier frequency estimate is available at the end of each frame, and if such estimate is proven to be reliable for future use, the current estimate in memory will be overwritten by the new estimate and the freshness of the frequency estimate is extended.

Abstract: A distributed antenna system includes network interfaces configured to receive signals from devices external to distributed antenna system and to convert signals to downlink serialized data streams; distributed antenna switch communicatively coupled to network interfaces by digital communication links, distributed antenna switch configured to receive downlink serialized data stream from network interfaces across corresponding digital communication link; distributed antenna switch further configured to aggregate downlink serialized data streams into aggregate downlink serialized data stream; remote antenna unit communicatively coupled to distributed antenna switch by digital communication link that receives aggregate downlink serialized data stream across digital communication link, remote antenna unit further configured to extract downlink serialized data streams from aggregate downlink serialized data stream; remote antenna unit having radio frequency converter configured to convert downlink serialized data

Abstract: A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. The data processor selects a set of QBOC correlations in accordance with a QBOC correlation function for the sampling period if the secondary amplitude exceeds the primary amplitude for the sampling period. The data processor uses either the BOC correlation function or the QBOC correlation function, whichever with greater amplitude, at each sampling period to provide an aggregate correlation function that supports unambiguous code acquisition of the received signal.

Abstract: A transmitter includes: first and second IFFT units that respectively generate first and second time domain signals from first and second modulated signals generated in first and second modulation schemes; a clipping noise signal generator that generates a clipping noise signal representing a difference between a combined signal of the first and second time domain signals and a specified threshold in a time period in which the power of the combined signal is higher than the threshold; first and second calculators that respectively subtract the clipping noise signals to which first and second coefficients are multiplied from the first and second time domain signals; first and second frequency filters that respectively filter output signals of the first and second calculators; and a combiner that generates a transmission signal including an output signal of the first frequency filter and an output signal of the second frequency filter.

Abstract: A circuit and a method are used estimate quality of the output of a wireless receiver. This quality measure is used to control the supply voltage and thereby provide power savings.

Abstract: Methods and apparatuses are provided that include selecting reference signal (RS) or other tones to utilize in estimating a channel for decoding one or more channels. Where the RS tones are interfered by other base stations, interference cancelation can be performed over the RS tones. Since interference can vary over the tones, interference cancelation can yield RS tones of varying quality. Thus, a quality of each of the RS tones can be determined, and at least a subset of the RS tones can be selected for estimating a channel. Additionally or alternatively, the RS tones can be weighted or otherwise classified for performing channel estimation using the RS tones.

Abstract: A method for decoding differentially modulated received symbols, the differentially modulated received symbols corresponding to a transmission of a differentially modulated version of a codeword out of a set of possible codewords, the received symbols being transferred onto resources of a channel, the resources being equally spaced. A receiver, for each possible codeword: obtains a vector of differentially demodulated symbols by differentially demodulating the differentially modulated received symbols obtained by combining two consecutive differentially modulated received symbols; calculates the product of each differentially demodulated symbol by the conjugate of the element of the codeword having the same rank within the codeword as the differentially demodulated received symbol; calculates the sum of the products; decodes the vector of differentially demodulated symbols by selecting the codeword for which the sum of the products is the maximum.

Abstract: A wireless charging in-band communication system includes a transmitter module that formats a message using CRC calculation and attaches the results of the CRC calculation to the message for message error detection. The transmitter includes channel encoding for message error correction. A modulation module performs biphase modulation for DC balanced signals and impedance switching to change reflected impedance seen by the source. A synchronization module prepending the message with a synchronization sequence having Golay complementary codes. Moreover, the in-band communication includes a receiver module that receives the message from the transmitter module. The receiver module includes an impedance sensing circuit to detect changes in the reflected impedance of the transmitter module. The receiver module includes a front end filter used for pulse shaping and noise rejection.

Abstract: Electric Vehicle Service Equipment (EVSE) and Electric Vehicle (EV) are disclosed n. In an example embodiment, a modem is coupled to the pilot wire that couples the EVSE and the EV. The modem transmits both pulse width modulation (PWM) command signals and power line communication (PLC) signals to a remote device via the pilot wire. The modem interleaves the PWM and PLC signals on the pilot wire so that latency requirements for the PWM signals are maintained. The modem supports parallel protocol stacks in which PLC signals are processed in a first path and PWM signals are processed in a second path that bypasses the first path and provides the PWM signals directly to a MAC layer. The modem may create a modified frame for the PLC signals to maintain the latency requirements.

Abstract: Aspects of a wireless apparatus and a method for handling a modulated signal include a frequency generator that produces a clock signal, a first synchronization circuit that generates a first sync enable signal based on an even edge of the clock signal, a second synchronization circuit that generates a second sync enable signal based on an even edge of the clock signal, a first divider having a first initial operating condition that generates a first IQ path based on the first sync enable signal, and a second divider having a second initial operating condition that generates a second IQ path based on the second sync enable signal, wherein the first and second operating conditions are not equal when initially powered.

Abstract: An embodiment of the time-variant channel estimation in an OFDM transmission system envisages the operations of: a) determining the received signal vector Yj,k for one or more of R receiving antennas, j=1, . . .

Abstract: Adaptive filtering is used to substantially cancel distortion in radio frequency (RF) signals. Such adaptive filtering can be used in an RF transmitting module to pre-compensate an RF signal with compensation (inverse) distortion to cancel inherent transmission path distortion from the RF signal. Adaptive filtering can also be used in a multi-carrier RF receiving module to cancel from a given carrier signal distortion due to cross talk from adjacent carrier signals. Adaptive filtering in an RF transceiver can be used to cancel from a received RF signal distortion arising from leakage of a transmit signal into the receive path.

Abstract: A method includes, in a mobile communication terminal, storing a mathematical model for computing a covariance matrix of data conveying signals that are received at the mobile communication terminal. At least a first data conveying signal is received in the mobile communication terminal, and one or more signal components required by the model are extracted from the first data conveying signal. A determination is made whether the model is suitable for computing the covariance matrix for the first data conveying signal based on a predefined rule. The covariance matrix is computed in the mobile communication terminal using at least one of the model and an empirical-based estimation of the covariance matrix. The covariance matrix is selected in response to the determination.

Abstract: A decision circuit includes: a first decision block to distinguish a first bit of bits using an amplitude of an analog signal as a discrimination point, the analog signal being an amplitude shift keyed signal; a superposition block to acquire an absolute value of a difference of the analog signal in respect to an amplitude center value of the analog signal by superposing divided analog signals; an inversion block to control inverting of the signal based on a first distinction result of the first decision block; a second decision block to distinguish a second bit of the bits based on an amplitude of an output signal from the inversion block and the discrimination point; and an output buffer to output the first distinction result and a second distinction result of the second decision block in synchronization with a clock.

Abstract: An apparatus includes a first squelch circuit and a second squelch circuit. The first squelch circuit is configured to detect possible squelch signals in a communication signal. The second squelch circuit is configured to selectively detect the possible squelch signals in the same communication signal. The second squelch circuit is further configured to operate in a low-power state responsive to the first squelch circuit detecting none of the possible squelch signals in the communication signal. The second squelch circuit is further configured to operate in a high-power state responsive to the first squelch circuit detecting one of the possible squelch signals in the communication signal.