A radio frequency circuit for processing a radio frequency signal. The circuit comprises a variable frequency oscillator system and a radio frequency signal processing circuit arranged to process a radio frequency signal using the output of the variable frequency oscillator system. A digitiser is arranged to receive the output of the radio frequency signal processing circuit and generate a digitised signal. A phase noise capture circuit is arranged to capture the phase noise in the output of the variable frequency oscillator system. The radio frequency circuit is arranged to compensate for the effect of the phase noise in the output of the variable frequency oscillator system on the output of the radio frequency signal processing circuit, by digitally processing the digitised signal generated by the digitiser using the output of the phase noise capture circuit.

The present disclosure provides a method for compensating gain flatness of a transceiver including: a method for compensating gain flatness of a receiver, which compensates gain flatness of a receiving channel by using a complex-coefficient FIR filter in digital domain; and a method for compensating gain flatness of a transmitter, which compensates gain flatness of a transmitting channel by using a complex-coefficient FIR filter in digital domain. The method according to the present disclosure can balance compensation accuracy and calculation amount flexibly, and can focus on compensating the gain flatness at an edge of a frequency band, obtaining good performance with less calculation amount.

A method of operating a communications system includes receiving a signal at a digital predistorter (DPD), introducing predistortion to the signal using the DPD, and converting the predistorted signal to an analog signal using a digital-to-analog converter having a first bandwidth. The method also includes amplifying the analog signal, sampling the amplified signal using an analog-to-digital converter having a second bandwidth less than the first bandwidth, and extracting coefficients of the DPD from the sampled signal.

Described herein are systems configured for carrier aggregation. Systems include a multiplexing circuit having a filter assembly, switching circuit with a switching path, and a switchable impedance. The filters can be designed so that when operated simultaneously (e.g., during multi-band operation) the same inductance can be used allowing the switching network to switch in a particular inductance into the path. The described systems can include an inductance that is coupled to an output port so that when operating in single-band mode, the different paths share the same inductance. Relative to other solutions, the described systems can improve performance (e.g., reduce insertion loss), reduce the number of components in the associated module, reduce manufacturing costs, and the like.

A digital radio frequency (RF) transmitter including processing circuitry configured to generate first through third pattern signals based on a pattern of an inphase (I)-quadrature (Q) binary data pair and a pattern of an inverted I-Q binary data pair, the first through third pattern signals having a same pattern and different phases, and a switched-capacitor digital-to-analog converter (SC-DAC) configured to remove an n-th harmonic component of an RF analog signal by amplifying the first through third pattern signals to have a certain magnitude ratio and synthesizing the amplified first through third pattern signals into the RF analog signal, where n is an integer of at least 3, may be provided.

A digital predistortion linearization method is provided for increasing the instantaneous or operational bandwidth for RF power amplifiers employed in wideband communication systems. Embodiments of the present invention provide a method of increasing DPD linearization bandwidth using a feedback filter integrated into existing digital platforms for multi-channel wideband wireless transmitters. An embodiment of the present invention utilizes a DPD feedback signal in conjunction with a low power band-pass filter in the DPD feedback path.

Described herein is an improved apparatus for increasing the performance of a modulator, which may function as an ADC. In one embodiment, the modulator comprises a voltage to current converter, a capacitor connected between two outputs of the voltage to current converter to receive a differential input current, and a switch that can switch between connecting each output of the voltage to current converter to ground while disconnecting the other output of the voltage to current converter. In this embodiment, the modulator has no common mode control loop, and no reference current. This results in decreased complexity, i.e., fewer components, as well as reduced noise.

A method of operating a communications system includes receiving a signal at a digital predistorter (DPD), introducing predistortion to the signal using the DPD, and converting the predistorted signal to an analog signal using a digital-to-analog converter having a first bandwidth. The method also includes amplifying the analog signal, sampling the amplified signal using an analog-to-digital converter having a second bandwidth less than the first bandwidth, and extracting coefficients of the DPD from the sampled signal.

This specification discloses methods and systems for implementing a chip integrated scope (i.e., chip scope (CS)), which is a feature that allows a user to scope RF signals (internally and externally to the DUT (device under test)), by using the RF receive path (including amplifier, filter, ADC, DSP) to capture and store signal traces. In some embodiments, this specification discloses methods and systems to enhance the resolution and accuracy of these signal traces by using raw and correction data for gain/phase compensation of gain/phase impairments introduced in the Rx (receiver) path. In some embodiments, the correction data is generated from one or more of the following: simulation data, characterization data, production test data.

A digital predistortion linearization method is provided for increasing the instantaneous or operational bandwidth for RF power amplifiers employed in wideband communication systems. Embodiments of the present invention provide a method of increasing DPD linearization bandwidth using a feedback filter integrated into existing digital platforms for multi-channel wideband wireless transmitters. An embodiment of the present invention utilizes a DPD feedback signal in conjunction with a low power band-pass filter in the DPD feedback path.