A method may comprise receiving and sampling a signal. The signal may encode a data packet. A slice may be generated and stored comprising a pair of values for each of a selected number of samples of the signal representing a correlation of the signal to reference functions in the receiver. The presence of the data packet may then be detected and the detected packet decoded from the stored slices. The generating and storing slices may be carried out as the received signal is sampled. The sampled values of the signal may be discarded as the slices are generated and stored. The slice representation of the signal can be manipulated to generate filters with flexible bandwidth and center frequency.

Systems and methods for classifying a modulation scheme of a wireless signal are described. In some embodiments, a system receives a wireless signal modulated based on a modulation scheme having a constant modulus. The system can generate a resampled signal from the wireless signal based on features extracted from the wireless signal and perform blind equalization on the resampled signal based on a constant modulus criterion to generate an equalized signal. Then, the system can cause a modulation classifier to classify the received wireless signal to a modulation scheme from a plurality of predetermined modulation schemes based on the equalized signal. By preconditioning the wireless signal to reduce feature variability imparted by a propagation channel onto the wireless signal, the system can increase the classification accuracy of the modulation classifier.

Systems and methods for classifying a modulation scheme of a wireless signal are described. In some embodiments, a system receives a wireless signal modulated based on a modulation scheme having a constant modulus. The system can generate a resampled signal from the wireless signal based on features extracted from the wireless signal and perform blind equalization on the resampled signal based on a constant modulus criterion to generate an equalized signal. Then, the system can cause a modulation classifier to classify the received wireless signal to a modulation scheme from a plurality of predetermined modulation schemes based on the equalized signal. By preconditioning the wireless signal to reduce feature variability imparted by a propagation channel onto the wireless signal, the system can increase the classification accuracy of the modulation classifier.

A front-end receiver includes a first mixer of a first channel, a second mixer of a second channel, and a switching circuit that is configured to select the first mixer or the second mixer during a particular time period. Upon being selected, one of the first mixer or the second mixer is configured to deliver a down-converted signal that down-converts a respective RF signal of either the first or second reception channel. As the tasks of down-conversion and multiplexing are combined at the mixer level, the first and second reception channels may share a baseband circuit while being able to provide a well-balanced metrics of channel isolation, low noise figure, and linearity.

A front-end receiver includes a first mixer of a first channel, a second mixer of a second channel, and a switching circuit that is configured to select the first mixer or the second mixer during a particular time period. Upon being selected, one of the first mixer or the second mixer is configured to deliver a down-converted signal that down-converts a respective RF signal of either the first or second reception channel. As the tasks of down-conversion and multiplexing are combined at the mixer level, the first and second reception channels may share a baseband circuit while being able to provide a well-balanced metrics of channel isolation, low noise figure, and linearity.

A receiver circuit includes a quadrature signal generator to generate an in-phase (I) signal and a quadrature (Q) signal from a local oscillator signal and an IQ phase sense and control circuit to generate a phase adjustment code responsive to a phase error between quadrature signals generated by a plurality of mixers. The receiver circuit also includes a phase corrector to adjust a phase difference between the I and Q signals from the quadrature signal generator to generate corrected I and Q signals to be provided to the plurality of mixers.

A receiver circuit includes a quadrature signal generator to generate an in-phase (I) signal and a quadrature (Q) signal from a local oscillator signal and an IQ phase sense and control circuit to generate a phase adjustment code responsive to a phase error between quadrature signals generated by a plurality of mixers. The receiver circuit also includes a phase corrector to adjust a phase difference between the I and Q signals from the quadrature signal generator to generate corrected I and Q signals to be provided to the plurality of mixers.

A reconstruction method for DCSK signals is provided. An information bit sequence to be transmitted is acquired, which is processed by serial-to-parallel conversion. A processed information bit sequence is input into a modulator for modulation to obtain a modulated signal matrix. Cross multiplication is performed between the modulated signal matrix and a chaotic signal to obtain an original information-bearing matrix, which is reconstructed according to a predetermined reconstruction matrix to obtain an information-bearing reconstruction matrix. A transmission symbol is generated according to the information-bearing reconstruction matrix and a reference signal matrix in combination with frame structure information of the transmission symbol, and is sent to a receiving end via a wireless network to demodulate a received signal according to a reconstruction matrix. A reconstruction device for DCSK signals is also provided.

A reconstruction method for DCSK signals is provided. An information bit sequence to be transmitted is acquired, which is processed by serial-to-parallel conversion. A processed information bit sequence is input into a modulator for modulation to obtain a modulated signal matrix. Cross multiplication is performed between the modulated signal matrix and a chaotic signal to obtain an original information-bearing matrix, which is reconstructed according to a predetermined reconstruction matrix to obtain an information-bearing reconstruction matrix. A transmission symbol is generated according to the information-bearing reconstruction matrix and a reference signal matrix in combination with frame structure information of the transmission symbol, and is sent to a receiving end via a wireless network to demodulate a received signal according to a reconstruction matrix. A reconstruction device for DCSK signals is also provided.

Methods and systems are described for obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus, applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors, recovering a demodulation signal from the carrier-modulated symbols, and generating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal.