A communication unit for performing soft-decision demodulation comprises a receiver that receives a transmitted signal having a first set of bits comprising k bits, selected from a set of 2.sup.k possible signals according to values of the k bits, and a second set of bits comprising Q.sub.m bits based on a phase rotation of the transmitted signal selected from a set of 2.sup.Qm possible rotations. The receiver comprises: a demodulator comprising a bank of 2.sup.k correlators and is configured to: detect a transmission of each possible transmitted signal, and output 2.sup.k phases of the correlator outputs as a third set of inputs. A de-mapper circuit receives the third set of inputs: determines statistics derived from a number of aggregated correlator output phase distributions of the third set of inputs; and calculates and outputs a second set of aposteriori soft bits comprising Q.sub.m soft bits.

Described are systems and methods for identifying the phase and polarization of independent modulation streams in quadrature channels of a coherent transmission system by using digital code. As a result, phase rotation and polarization of streams that during transmission may have become rotated and swapped around in the channel are correctly labeled and depermuted according to a known and predictable order.

A radar system processes signals in a flexible, adaptive manner to determine range, Doppler (velocity) and angle of objects in an environment. The radar system processes the received signal to achieve different objectives depending on one or more of a selected range resolution, a selected velocity resolution, and a selected angle of arrival resolution, as defined by memory requirements and processing requirements. The system allows improved resolution of range, Doppler and/or angle depending on the memory requirements and processing requirements. The system also adapts to changing environmental conditions including interfering radio signals.

This disclosure describes systems, methods, and devices related to correlation reduction. A device may generate a sequence of pseudo-random symbols associated with a sounding signal to be transmitted to a first station device. The device may apply a modifier to the sequence of pseudo-random symbols. The device may generate a secure sounding signal from the modified sequence of pseudo-random symbols. The device may send the secure sounding signal to a first station device.

Described are systems and methods for identifying the phase and polarization of independent modulation streams in quadrature channels of a coherent transmission system by using digital code. As a result, phase rotation and polarization of streams that during transmission may have become rotated and swapped around in the channel are correctly labeled and depermuted according to a known and predictable order.

Certain disclosed methods, apparatus, and systems enable improved communication on a multiphase communication link through improved encoding techniques and protocol. A data communication apparatus has a plurality of line drivers configured to couple the apparatus to a 3-wire link, and a data encoder configured to encode at least 3 bits of binary data in each transition between two symbols that are consecutively transmitted by the plurality of line drivers over the 3-wire link such that each pair of consecutively-transmitted symbols comprises two different symbols. Each symbol defines signaling states of the 3-wire link during an associated symbol transmission interval such that each wire of the 3-wire link is in a different signaling state from the other wires of the 3-wire link during the associated symbol transmission interval. Data may be encoded using a combination of 3-phase and pulse amplitude modulation.

Described are systems and methods for identifying the phase and polarization of independent modulation streams in quadrature channels of a coherent transmission system by using digital code. As a result, phase rotation and polarization of streams that during transmission may have become rotated and swapped around in the channel are correctly labeled and depermuted according to a known and predictable order.

System and method for processing an analog signal. For example, a demodulator for processing an analog signal includes one or more analog-to-digital converters configured to receive an analog signal and generate a digital signal based at least in part on the analog signal, and a correlator coupled to the one or more analog-to-digital converters and configured to generate a stream of correlation results including a first plurality of correlation results, a second plurality of correlation results, and a third plurality of correlation results. The first plurality of correlation results is different from the second plurality of correlation results by at least one correlation result, and the second plurality of correlation results is different from the third plurality of correlation results by at least another correlation result.

A High-Order PSK Signaling (HOPS) communications system which adapts sequence-based spread spectrum signaling techniques to the needs of low-power commercial standards. A HOPS signal generation apparatus incudes a seed calculator configured to calculate a series of seed vectors in response to a plurality of time-evolving key values wherein each of the seed vectors includes a plurality of index values calculated based upon the current key values. A sequence generator is configured to generate a series of time-evolving spreading sequences using the series of seed vectors. A modulator is operative to generate the communications signal by spreading the data signal using the spreading sequences. A transmitter transmits an analog version of the communications signal.

The present disclosure provides a method for compensating an imbalance between an I path and a Q path of a receiver. The method includes: sending a cosine signal and a sine signal through a signal generator, transmitting the cosine signal and the sine signal in the I path and Q path respectively; calculating autocorrelation values of the I path and the Q path in the signal receiving direction; determining a comparison result of amplitudes of the cosine signal received by the I path and the sine signal received by the Q path according to the autocorrelation values; calculating an adjustment compensation value of an analog domain gain amplifier, and an amplitude value and a phase value in a digital domain according to the comparison result of amplitudes; and compensating and adjusting the signal according to the adjustment compensation value, the amplitude value and the phase value.