A radio frequency (RF) unit and a method for RF isolation. The RF unit includes first and second RF couplers, an RF filter, and an RF canceler connected in parallel with the RF filter. The first RF coupler is configured to receive an input signal. The RF filter is configured to receive a first portion of the input signal from the first RF coupler and attenuate frequencies outside of a passband of the RF filter from the first portion of the input signal. The RF canceler is configured to receive a second portion of the input signal from the first RF coupler and generate a cancellation signal from the second portion of the input signal based on a target frequency band of the RF canceler. The second RF coupler is configured to combine the cancellation signal with an output of the RF filter to generate an output signal.

Phase shifters such as networks that can be used in MMIC (Monolithic Microwave Integrated Circuit) and hybrid digital phase shifters, for low loss, wide bandwidth, and high linearity. A digital phase shifter includes input port for receiving signals and output ports for transmitting the signals. Multiple transmission lines are arranged between the input and output ports of the phase shifter. The transmission lines are arranged in a ring with first pair of the transmission lines which are arranged in series in a first path and second pair of the transmission lines arranged in series in a second path. One of the transmission lines of the first and second pairs include quarter-wave hybrid coupled line with coupled-ports and through-ports terminated in short-circuit. Hybrid coupled line can be a Lange coupler with or without RF crossover.

Phase shifters such as networks that can be used in MMIC (Monolithic Microwave Integrated Circuit) and hybrid digital phase shifters, for low loss, wide bandwidth, and high linearity. A digital phase shifter includes input port for receiving signals and output ports for transmitting the signals. Multiple transmission lines are arranged between the input and output ports of the phase shifter. The transmission lines are arranged in a ring with first pair of the transmission lines which are arranged in series in a first path and second pair of the transmission lines arranged in series in a second path. One of the transmission lines of the first and second pairs include quarter-wave hybrid coupled line with coupled-ports and through-ports terminated in short-circuit. Hybrid coupled line can be a Lange coupler with or without RF crossover.

There is provided a method of determining filter coefficients for an audio filter system including a number, N≥2, of filter paths for enabling processing of N audio channels, one filter path per channel, wherein each filter path includes at least one audio filter for performing the processing of the corresponding channel. The method includes providing a common set of filter design parameters for a pair of audio filters belonging to different filter paths, including phase difference information representing an inter-channel phase difference and frequency information representing a frequency value as filter design parameters; and determining filter coefficients for the pair of audio filters at least partly based on the common set of filter design parameters.

A signal processing method performed by a processor of a signal processing device and includes: generating a fundamental matrix according to at least one set of fundamental coefficients; generating a phase-shifted matrix according to a predetermined phase shift and the fundamental matrix; and generating an output sequence according to an input sequence and the phase-shifted matrix. The set of fundamental coefficients is used to generate at least one bit of a code sequence, the output sequence is a phase-shifted version of the input sequence being shifted by k cycle(s), and k is the predetermined phase shift.

A signal processing method performed by a processor of a signal processing device and includes: generating a fundamental matrix according to at least one set of fundamental coefficients; generating a phase-shifted matrix according to a predetermined phase shift and the fundamental matrix; and generating an output sequence according to an input sequence and the phase-shifted matrix. The set of fundamental coefficients is used to generate at least one bit of a code sequence, the output sequence is a phase-shifted version of the input sequence being shifted by k cycle(s), and k is the predetermined phase shift.

A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.

A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.

There is provided a method of determining filter coefficients for an audio filter system including a number, N2, of filter paths for enabling processing of N audio channels, one filter path per channel, wherein each filter path includes at least one audio filter for performing the processing of the corresponding channel. The method includes providing a common set of filter design parameters for a pair of audio filters belonging to different filter paths, including phase difference information representing an inter-channel phase difference and frequency information representing a frequency value as filter design parameters; and determining filter coefficients for the pair of audio filters at least partly based on the common set of filter design parameters.

Systems and methods are provided for channelizing. A first stage can provide a WOLA filter bank that can apply a single multiplier resource to perform window weighting for multiple WOLA filter banks. The first stage can remove mixer-based post FFT adjustment and provide equal functionality with a particular modification of tuning mixers at inputs of second stage FIR paths. The first stage can include a variable decimation, using a particular implementation of variable sample block size.